@article {164, title = {Competing Intermolecular and Molecule{\textendash}Surface Interactions: Dipole{\textendash}Dipole-Driven Patterns in Mixed Carborane Self-Assembled Monolayers}, journal = {Chemistry of Materials}, volume = {36}, year = {2024}, month = {February 8, 2024}, pages = {2085-2095}, type = {Article}, chapter = {2085}, abstract = {

Carboranedithiol isomers adsorbing with opposite orientations of their dipoles on surfaces are self-assembled together to form mixed monolayers where both lateral dipole{\textendash}dipole and lateral thiol{\textendash}thiolate (S{\textendash}H{\textperiodcentered}{\textperiodcentered}{\textperiodcentered}S) interactions provide enhanced stability over single-component monolayers. We demonstrate the first instance of the ability to map individual isomers in a mixed monolayer using the model system carboranedithiols on Au{111}. The addition of methyl groups to one isomer provides both an enhanced dipole moment and extra apparent height for differentiation via scanning tunneling microscopy (STM). Associated computational investigations rationalize favorable interactions of mixed pairs and the associated stability changes that arise from these interactions. Both STM images and Monte Carlo simulations yield similarly structured mixed monolayers, where approximately 10\% of the molecules have reversed dipole moment orientations but no direct chemical attachment to the surface, leading to homogeneous monolayers with no apparent phase separation. Deprotonating the thiols by depositing the molecules under basic conditions eliminates the lateral S{\textendash}H{\textperiodcentered}{\textperiodcentered}{\textperiodcentered}S interactions while accentuating the dipole{\textendash}dipole forces. The molecular system investigated is composed of isomeric molecules with opposite orientations of dipoles and identical surface packing, which enables the mapping of individual molecules within the mixed monolayers and enables analyses of the contributions of the relatively weak lateral interactions to the overall stability of the assemblies.

}, keywords = {2D assembly, boron, carborane, Cluster Molecules, Dipole-dipole, Molecular interactions, Molecular structure, scanning tunneling microscopy, Supramolecular chemistry}, doi = {https://doi.org/10.1021/acs.chemmater.3c03210}, url = {https://pubs.acs.org/doi/10.1021/acs.chemmater.3c03210}, author = {Katherine E. White and Erin M. Avery and Edison Cummings and Zixiang Hong and Jens Langecker and Aliaksei Vetushka and Michal Dusek and Jan Machacek and Jakub Vi{\v s}n{\'a}k and Jan Endres and Zdenek Bastl and Ersen Mete and Anastassia N. Alexandrova and Tomas Base and Paul S. Weiss} } @article {161, title = {Carborane-thiol protected copper nanoclusters: Stimuli-responsive materials with tunable phosphorescence}, journal = {Chemical Science}, volume = {14}, year = {2023}, month = {12/2023}, pages = {1613-1626}, type = {Article}, chapter = {1613}, abstract = {

Atomically precise nanomaterials with tunable solid-state luminescence attract global interest. In this work, we present a new class of thermally stable isostructural tetranuclear copper nanoclusters (NCs), shortly Cu4@oCBT, Cu4@mCBT and Cu4@ICBT, protected by nearly isomeric carborane thiols: ortho-carborane-9-thiol, meta-carborane-9-thiol and ortho-carborane 12-iodo 9-thiol, respectively. They have a square planar Cu4 core and a butterfly-shaped Cu4S4 staple, which is appended with four respective carboranes. For Cu4@ICBT, strain generated by the bulky iodine substituents on the carboranes makes the Cu4S4 staple flatter in comparison to other clusters. High-resolution electrospray ionization mass spectrometry (HR ESI-MS) and collision energy-dependent fragmentation, along with other spectroscopic and microscopic studies confirm their molecular structure. Although none of these clusters show any visible luminescence in solution, bright μs-long phosphorescence is observed in their crystalline forms. The Cu4@oCBT and Cu4@mCBT NCs are green emitting with quantum yields (Ф) of 81 and 59 \%, respectively, whereas Cu4@ICBT is orange emitting with a Φ of 18 \%. Density functional theory (DFT) calculations reveal the nature of their respective electronic transitions. The green luminescence of Cu4@oCBT and Cu4@mCBT clusters get shifted to yellow after mechanical grinding, but it is regenerated after exposure to solvent vapour, whereas the orange emission of Cu4@ICBT is not affected by mechanical grinding. Structurally flatten Cu4@ICBT didn{\textquoteright}t show mechonoresponsive luminescence in contrast to other clusters, having bent Cu4S4 structures. Cu4@oCBT and Cu4@mCBT are thermally stable up to 400 {\textdegree}C. The Cu4@oCBT retained green emission even upon heating to 200 {\textdegree}C under ambient conditions, while Cu4@mCBT changed from green to yellow in the same window. This is the first report on structurally flexible carborane thiol appended Cu4 NCs having stimuli-responsive tunable solid-state phosphorescence.

}, keywords = {boron, Cluster, Copper, Cu4L4, Phosphorescence, Responsive}, doi = {https://doi.org/10.1039/D2SC06578A}, url = {https://pubs.rsc.org/en/content/articlelanding/2023/sc/d2sc06578a}, author = {Arijit Jana and Madhuri Jash and Wakeel Ahmed Dar and Jayoti Roy and Papri Chakraborty and Paramasivam Ganesan and Sergei Lebedkin and Kaplan Kirakci and Sujan Manna and P. K. Sudhadevi Antharjanam and Jan Machacek and Monika Kucerakova and Sundargopal Ghosh and Kamil Lang and Manfred Kappes and Tomas Base and T. Pradeep} } @article {162, title = {A Luminescent Cu4 Cluster Film Grown by Electrospray Deposition: A Nitroaromatic Vapour Sensor}, journal = {Nanoscale}, year = {2023}, type = {Communication}, abstract = {

We present the fabrication and use of a film of carborane-thiol protected tetranuclear copper cluster with characteristic orange luminescence using ambient electrospray deposition (ESD). Charged microdroplets of the clusters produced by an electrospray tip deposit clusters at an air-water interface to form a film. Different microscopic and spectroscopic techniques characterized the porous surface structure of the film. Visible and rapid quenching of the emission of the film upon exposure to 2-nitrotoluene (2-NT) vapours at ambient condition was observed. Density functional theory (DFT) calculations established the favourable binding sites of 2-NT with the cluster. Desorption of 2-NT upon heating recovered the original luminescence, demonstrating the reusability of the sensor. Stable emission upon exposure to different organic solvents and quenching of it upon the exposure to 2, 4-dinitrotoluene and picric acid showed selectivity of the film to nitroaromatic species.

}, keywords = {carborane, Copper, luminescence, nanocluster, nitro organic, sensor}, doi = {https://doi.org/10.1039/D3NR00416C}, url = {https://pubs.rsc.org/en/content/articlelanding/2023/nr/d3nr00416c}, author = {Arijit Jana and B K Spoorthi and Akhil S Nair and Biswarup Pathak and Tomas Base and Thalappil Pradeep} } @article {163, title = {Macropolyhedral syn-B18H22, the {\textquotedblleft}Forgotten{\textquotedblright} Isomer}, journal = {Journal of the American Chemical Society}, volume = {145}, year = {2023}, month = {August 2, 2023}, pages = {17975-17986}, chapter = {17975}, abstract = {

The chemistry and physics of macropolyhedral B18H22 clusters have attracted significant attention due to the interesting photophysical properties of anti-B18H22 (blue emission, laser properties) and related potential applications. We have focused our attention on the {\textquotedblleft}forgotten{\textquotedblright} syn-B18H22 isomer, which has received very little attention since its discovery compared to its anti-B18H22 isomer, presumably because numerous studies have reported this isomer as nonluminescent. In our study, we show that in crystalline form, syn-B18H22 exhibits blue fluorescence and becomes phosphorescent when substituted at various positions on the cluster, associated with peculiar microstructural-dependent effects. This work is a combined theoretical and experimental investigation that includes the synthesis, separation, structural characterization, and first elucidation of the photophysical properties of three different monothiol-substituted cluster isomers, [1-HS-syn-B18H21] 1, [3-HS-syn-B18H21] 3, and [4-HS-syn-B18H21] 4, of which isomers 1 and 4 have been proved to exist in two different polymorphic forms. All of these newly substituted macropolyhedral cluster derivatives (1, 3, and 4) have been fully characterized by NMR spectroscopy, mass spectrometry, single-crystal X-ray diffraction, IR spectroscopy, and luminescence spectroscopy. This study also presents the first report on the mechanochromic shift in the luminescence of a borane cluster and generally enriches the area of rather rare boron-based luminescent materials. In addition, we present the first results proving that they are useful constituents of carbon-free self-assembled monolayers.

}, keywords = {boron, boron hydride, Cluster, luminescence, macropolyhedral, NMR, PXRD, SAM, self-assembly, single crystal, solid state, syn-B18H22, XPS}, doi = {https://doi.org/10.1021/jacs.3c05530}, url = {https://pubs.acs.org/doi/10.1021/jacs.3c05530}, author = {Deepak Kumar Patel and B. S. Sooraj and Kaplan Kirakci and Jan Machacek and Monika Kucerakova and Jonathan Bould and Michal Dusek and Martha Frey and Christof Neumann and Sundargopal Ghosh and Andrey Turchanin and Thalappil Pradeep and Tomas Base} } @article {158, title = {Carboranethiol-Protected Propeller-Shaped Photoresponsive Silver Nanomolecule}, journal = {Inorganic Chemistry}, volume = {61}, year = {2022}, month = {May 27, 2022}, pages = {8593-8603}, type = {Article}, chapter = {8593}, abstract = {

We report the synthesis, structural characterization, and photophysical properties of a propeller-shaped Ag21 nano-molecule with six rotary arms, protected with m-carborane-9-thiol (MCT) and triphenylphosphine (TPP) ligands. Structural analysis reveals that the nanomolecule has an Ag13 central icosahedral core with six directly connected silver atoms and two more silver atoms connected through three Ag-S-Ag bridging motifs. While 12 MCT ligands protect the core through metal-thiolate bonds in a 3-6-3-layered fashion, two TPP ligands solely protect the two bridging silver atoms. Interestingly, the rotational orientation of a silver sulfide staple motif is opposite to the orientation of carborane ligands, resembling the existence of a bidirectional rotational orientation in the nanomolecule. Careful analysis reveals that the orientation of carborane ligands on the cluster{\textquoteright}s surface resembles an assembly of double rotors. The zero circular dichroism signal indicates its achiral nature in solution. There are multiple absorption peaks in its UV-vis absorption spectrum, characteristic of a quantized electronic structure. The spectrum appears as a fingerprint for the cluster. High-resolution electrospray ionization
mass spectrometry proves the structure and composition of the nanocluster in solution, and systematic fragmentation of the molecular ion starts with the loss of surface-bound ligands with increasing collision energy. Its multiple optical absorption features are in good agreement with the theoretically calculated spectrum. The cluster shows a narrow near-IR emission at 814 nm with a Stokes shift of 355 nm. The Ag21 nanomolecule is thermally stable at ambient conditions up to 100 {\textdegree}C. However, white-light illumination (lamp power = 120-160 W) shows photosensitivity, and this induces structural distortion, as confirmed by changes in the Raman and electronic absorption spectra. Femtosecond and nanosecond transient absorption studies reveal an exceptionally stable excited state having a lifetime of 3.26 {\textpm} 0.02 μs for the carriers, spread over a broad wavelength region of 500-650 nm. The formation of core-centered long-lived carriers in the excited state is responsible for the observed light-activated structural distortion.

}, keywords = {Ag21, boron, carborane, clusters, double rotor, luminescence, silver, thiol}, doi = {https://doi.org/10.1021/acs.inorgchem.2c00186}, url = {https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c00186}, author = {Arijit Jana and Parvathy M Unnikrishnan and Ajay K Poonia and Jayoti Roy and Madhuri Jash and Ganesan Paramasivam and Jan Machacek and Kumaran Nair Valsala Devi Adarsh and Tomas Base and Thalappil Pradeep} } @article {157, title = {Light-Activated Intercluster Conversion of an Atomically Precise Silver Nanocluster}, journal = {ACS Nano}, volume = {15}, year = {2021}, pages = {15781-15793}, type = {Full Article}, abstract = {

Noble metal nanoclusters protected with carboranes, a 12-vertex, nearly icosahedral boron{\textendash}carbon framework system, have received immense attention due to their different physicochemical properties. We have synthesized ortho-carborane-1,2-dithiol (CBDT) and triphenylphosphine (TPP) coprotected [Ag42(CBDT)15(TPP)4]2{\textendash} (shortly Ag42) using a ligand-exchange induced structural transformation reaction starting from [Ag18H16(TPP)10]2+ (shortly Ag18). The formation of Ag42 was confirmed using UV{\textendash}vis absorption spectroscopy, mass spectrometry, transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, and multinuclear magnetic resonance spectroscopy. Multiple UV{\textendash}vis optical absorption features, which exhibit characteristic patterns, confirmed its molecular nature. Ag42 is the highest nuclearity silver nanocluster protected with carboranes reported so far. Although these clusters are thermally stable up to 200 {\textdegree}C in their solid state, light-irradiation of its solutions in dichloromethane results in its structural conversion to [Ag14(CBDT)6(TPP)6] (shortly Ag14). Single crystal X-ray diffraction of Ag14 exhibits Ag8{\textendash}Ag6 core{\textendash}shell structure of this nanocluster. Other spectroscopic and microscopic studies also confirm the formation of Ag14. Time-dependent mass spectrometry revealed that this light-activated intercluster conversion went through two sets of intermediate clusters. The first set of intermediates, [Ag37(CBDT)12(TPP)4]3{\textendash} and [Ag35(CBDT)8(TPP)4]2{\textendash} were formed after 8 h of light irradiation, and the second set comprised of [Ag30(CBDT)8(TPP)4]2{\textendash}, [Ag26(CBDT)11(TPP)4]2{\textendash}, and [Ag26(CBDT)7(TPP)7]2{\textendash} were formed after 16 h of irradiation. After 24 h, the conversion to Ag14 was complete. Density functional theory calculations reveal that the kernel-centered excited state molecular orbitals of Ag42 are responsible for light-activated transformation. Interestingly, Ag42 showed near-infrared emission at 980 nm (1.26 eV) with a lifetime of \>1.5 μs, indicating phosphorescence, while Ag14 shows red luminescence at 626 nm (1.98 eV) with a lifetime of 550 ps, indicating fluorescence. Femtosecond and nanosecond transient absorption showed the transitions between their electronic energy levels and associated carrier dynamics. Formation of the stable excited states of Ag42 is shown to be responsible for the core transformation.

}, keywords = {carboranes silver nanoclusters intercluster conversion near-infrared emission luminescence ultrafast electron dynamics}, doi = {https://doi.org/10.1021/acsnano.1c02602}, url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.1c02602}, author = {Arijit Jana and Madhuri Jash and Ajay Kumar Poonia and Ganesan Paramasivam and Md Rabiul Islam and Papri Chakraborty and Sudhadevi Antharjanam and Jan Machacek and Sundargopal Ghosh and Kumaran Nair Valsala Devi Adarsh and Tomas Base and Thalappil Pradeep} } @article {159, title = {{\v R}e{\v z} na chemick{\'e} map{\v e} sv{\v e}ta}, journal = {Nase VESNICE - Zpravodaj obce Husinec}, volume = {04}, year = {2021}, month = {04/2021}, pages = {31}, type = {Popular}, author = {Tomas Base} } @article {156, title = {The Au25(SR)18 cluster carrying icosahedral dodecaborate and glutathione ligands: A spectroscopic view}, journal = {Journal of Physics and Chemistry of Solids}, year = {2020}, type = {Primary research article}, abstract = {

The functionality of Au25(S-glutathione)18 clusters change when some of the ligands in the cluster shell are replaced for other species. In this study we report on the synthesis and characterisation of a new cluster in which undecahydro-closo-dodecaborate thiolates are introduced as constituents of the shell surrounding the gold core. This is the first reported example in which the Au13 core of the Au25(S-glutathione)18 cluster is covered with an Au{\textendash}S{\textendash}B linkage instead of an Au{\textendash}S{\textendash}C on the dimeric shell units using a ligand exchange reaction. The spectra of the new cluster species clearly indicate a successful ligand exchange while retaining the gold core with undisrupted semirings containing both thiolate species. The resulting clusters were identified as Au25 [(S-glutathione)18-x (S-closo-borate)x-)] (x\ =\ 3, 4). Despite the achiral character of the closo-borate thiolates entering the semiring, increased chirality traces were observed in the high-energy region. Circular dichroism (CD) responses are ligand dependent and provide a fingerprint characteristic of the ligands present in the cluster. The next generation of such surface functionalized clusters provides unique base for computational and application studies.

}, keywords = {Chirality, Coating, Optoelectronic nanomaterials, Spectroscopy}, doi = {https://doi.org/10.1016/j.jpcs.2020.109838}, url = {https://www.sciencedirect.com/science/article/pii/S0022369720307411?via\%3Dihub}, author = {Eva Valusova and Maria Kanuchova and Tomas Base and Viktor Viglasky and Marian Antalik} } @article {155, title = {Influence of Terminal Carboxyl Group on Structure and Reactivity of Functionalized m-Carboranethiolate Self-Assembled Monolayers}, journal = {Chemistry of Materials}, volume = {32}, year = {2020}, month = {07/2020}, pages = {6800-6809}, type = {Article}, chapter = {6800}, abstract = {

The structure and function of self-assembled monolayers (SAMs) at the nanoscale are determined by the steric and electronic effects of their building blocks. Carboranethiol molecules form pristine monolayers that provide tunable two-dimensional systems to probe lateral and interfacial interactions. Additional ω-functionality, such as carboxyl groups, can be introduced to change the properties of the exposed surfaces. Here, two geometrically similar isomeric m-carborane analogs of m-mercaptobenzoic acid, 1 COOH-7-SH-1,7-C2B10H10 and racem-1-COOH-9-SH-1,7-C2B10H10, are characterized and their SAMs on Au{111} are examined. The latter isomer belongs to the rare group of chiral cage molecules and becomes, to our knowledge, the first example assembled on Au{111}. Although different in symmetry, molecules of both isomers assemble into similar hexagonal surface patterns. The nearest neighbor spacing of 8.4 {\textpm} 0.4 {\r A} is larger than that of non-carboxylated isomers, consistent with the increased steric demands of the carboxyl groups. Computational modeling reproduced this spacing and suggests a tilt relative to the surface normal. However, tilt domains are not observed experimentally, suggesting the presence of strong lateral interactions. Analyses of the influence of the functional groups through the pseudo-aromatic m carborane skeleton showed that the thiol group attached to either carbon or boron atoms increases the carboxyl group acidity in solution. In contrast, the acidity of the exposed carboxyl group in the SAMs decreases upon surface attachment; computational analyses suggest that the driving force of this shift is the dielectric of the environment in the monolayer as a result of confined intermolecular interactions, proximity to the Au surface, and partial desolvation.

}, keywords = {acidity, carborane, carboxyl, monolayer, SAM, self-assembly}, doi = {https://doi.org/10.1021/acs.chemmater.0c02722}, url = {https://pubs.acs.org/doi/10.1021/acs.chemmater.0c02722}, author = {Dominic P Goronzy and Jan Stanek and Erin Avery and Han Guo and Zdenek Bastl and Michal Dusek and Nathan M Gallup and Saliha Gun and Monika Kucerakova and Brian J Levandowski and Jan Machacek and Vaclav Sicha and John C Thomas and Adem Yavuz and K N Houk and M Fatih Danisman and Ersen Mete and Anastassia N Alexandrova and Tomas Base and Paul S Weiss} } @article {152, title = {Formation of Highly Ordered Terminal Alkyne Self-Assembled Monolayers on the Au{111} Surface through Substitution of 1-Decaboranethiolate}, journal = {J. Phys. Chem. C}, volume = {123}, year = {2019}, pages = {1348{\textendash}1353}, abstract = {

The reaction aimed at completing and closing the open cages of 1-decaboranethiol self-assembled monolayers (SAMs) on Au{111} with 4-phenyl-1-butyne results in highly ordered monolayers of 4-phenyl-1-butyne. The initially disordered 1-decaboranethiolate changed into ordered (√3{\texttimes}√3)R 30{\textdegree} lattices on Au{111} typical of alkyne SAMs, indicating the complete substitution of 1-decaboranethiolate moieties, as determined by nanoscale imaging with scanning tunneling microscopy and X-ray photoelectron spectroscopy. Vibrational spectroscopy results indicate that the process happens gradually and that alkynyl groups are not totally oxidized in the ordered 4-phenyl-1-butyne monolayer.

}, keywords = {alkyne, decaborane, gold, self-assembly, surface, thiol}, doi = {10.1021/acs.jpcc.8b11033}, url = {https://pubs.acs.org/doi/10.1021/acs.jpcc.8b11033}, author = {Shenkai Wang and Dominic P Goronzy and Thomas D Young and Natcha Wattanatorn and Logan Stewart and Tomas Base and Paul S Weiss} } @article {153, title = {Icosahedral Carbaboranes with Peripheral Hydrogen{\textendash} Chalcogenide Groups: Structures from Gas Electron Diffraction and Chemical Shielding in Solution}, journal = {Chemistry A European Journal}, volume = {25}, year = {2019}, month = {February 11, 201}, pages = {2313-2321}, type = {Full paper}, chapter = {2313}, abstract = {

Hydrochalcogeno carbaboranes: Icosahedral carbaboranes with thiol and selenol groups were prepared and their structures determined by gas electron diffraction augmented by ab initio calculated data (see figure). A method for quantifying the experimental contribution to the structural parameters was developed and tested. Comparison of NMR chemical shifts in solution with quantum-chemically calculated values allowed further structural information to be retrieved.

}, keywords = {carborane-diselenol, carborane-dithiol, gass phase electron diffraction, GPE, sturcture}, doi = {DOI : 10.1002/chem.201805145}, url = {https://onlinelibrary.wiley.com/doi/10.1002/chem.201805145}, author = {Tomas Base and Josef Holub and Jindrich Fanfrlik and Drahomir Hnyk and Paul L Lane and Derek A Wann and Yury V Vishnevskiy and Denis Tikhonov and Christian G Reuter and Norbert W Mitzel} } @article {154, title = {When does a supramolecular synthon fail? Comparison of bridgehead-functionalized adamantanes: the tri- and tetra- amides and amine hydrochlorides}, journal = {Crystal Growth \& Design}, year = {2019}, month = {July 12, 2019}, type = {Full paper}, abstract = {

1,3,5-trisubstituted adamantane carboxamide and amine hydrochloride, Ad(CONH2)3 {\textperiodcentered} 2.5H2O and [Ad(NH3)3]Cl3 {\textperiodcentered} H2O (Ad = adamant-n-yl) respectively, crystallized from aqueous solutions, possess crystal structures with predictable H-bonded assembly, consistent with the C3v symmetry of the building blocks. The triamide structure consists of interpenetrated hexagonal networks, sustained by the well-known cyclic H-bonded bis-amide synthon, R22(8), which ensures linear connectivity. The structure of the triamine hydrochloride, assembled through the tetrahedral {RN+H3---(Cl-)3} synthon, features a remarkably symmetric assembly with narrow trigonal pore-channels, hosting water molecules. The structures of the tetrahedral 1,3,5,7-tetrasubstituted Ad(CONH2)4 and [Ad(NH3)4]Cl4, obtained similarly, demonstrate a formal prediction failure of synthon based approach. Instead of the anticipated bis-amide synthon based diamond network (1.485 g cm-3) analogous to the 5-fold interpenetrated paradigmatic structure of Ad(COOH)4, a non-interpenetrated assembly, sustained by a dense network of H-bonds, is realized (1.433 g cm-3). Lessened geometric regularity was also found in the tetrahydrochloride salt assembled via 5-connected nodes, {RN+H3---(Cl-)4}, which involve a bifurcated H-bond. The failures of the supramolecular synthons in these simple cases could be interpreted either in terms of symmetry and/or limitations associated with the {\textquoteleft}synthon-density{\textquoteright}. A potential machine learning approach oriented on heuristic retrosupramolecular synthesis relies on such selected high-weight conceptual cases.

}, keywords = {adamantane, amide, amine, crystal structure, H-bond, hydrochloride, prediction, supramolecular synthon, violation}, doi = {https://doi.org/10.1021/acs.cgd.9b00594}, url = {https://pubs.acs.org/doi/10.1021/acs.cgd.9b00594}, author = {Ishtvan Boldog and Guido Reiss and Kostiantyn V. Domasevitch and Tomas Base and Stefan Braese} } @article {149, title = {Acid-Base Control of Valency within Carboranedithiol Self-Assembled Monolayers: Molecules Do the Can-Can}, journal = {ACS Nano}, year = {2018}, type = {Full paper}, abstract = {

We use simple acid-base chemistry to control the valency in self-assembled monolayers of two different carboranedithiol isomers on Au{111}. Monolayer formation proceeds via Au-S bonding, where manipulation of pH prior to or during deposition enables the assembly of dithiolate species, monothiol/monothiolate species, or combination. Scanning tunneling microscopy (STM) images identify two distinct binding modes in each unmodified monolayer, where simultaneous spectroscopic imaging confirms different dipole offsets for each binding mode. Density functional theory calculations and STM image simulations yield detailed understanding of molecular chemisorption modes and their relation with the STM images, including inverted contrast with respect to the geometric differences found for one isomer. Deposition conditions are modified with controlled equivalents of either acid or base, where the coordination of the molecules in the monolayers is controlled by protonating or deprotonating the second thiol/thiolate on each molecule. This control can be exercised during deposition to change the valency of the molecules in the monolayers, a process that we affectionately refer to as the {\textquotedblleft}can-can.{\textquotedblright} This control enables us to vary the density of molecule-substrate bonds by a factor of two without changing the molecular density of the monolayer.

}, keywords = {carborane, dipoles, molecules switch, nanoscience, scanning tunneling microscopy, self-assembled monolayer, self-assembly, two dimensional}, doi = {10.1021/acsnano.7b09011}, url = {https://pubs.acs.org/doi/10.1021/acsnano.7b09011}, author = {John C Thomas and Dominic P. Goronzy and Andrew C Serino and Harsharn S Auluck and Olivia R Irving and Elisa Jimenez-Izal and Jacqueline M Deirmenjian and Jan Machacek and Philippe Sautet and Anastassia N Alexandrova and Tomas Base and Paul S Weiss} } @article {151, title = {Kdy{\v z} molekuly tan{\v c}{\'\i} kank{\'a}n (Interview, in Czech)}, journal = {AB / Akadamick{\'y} bulletin}, volume = {04}, year = {2018}, month = {04/2018}, pages = {12-14}, type = {Rozhovor (Interview)}, abstract = {

Slou{\v c}eniny boru tvo{\v r}{\'\i} rozmanit{\'e} strukturn{\'\i} {\'u}tvary. Tom{\'a}{\v s} Ba{\v s}e a jeho kolegov{\'e} z {\'U}stavu anorganick{\'e} chemie AV{\v C}R p{\v r}ipravuj{\'\i} speci{\'a}ln{\'\i} velk{\'a} seskupen{\'\i} atom{\r u} zvan{\'a} klastry, pozm{\v e}{\v n}uj{\'\i} je pomoc{\'\i} organick{\'y}ch funk{\v c}n{\'\i}ch skupin a zkoumaj{\'\i} jejich jedine{\v c}n{\'e} vlastnosti. Dlouhodob{\'y} systematick{\'y} v{\'y}zkum tzv. klastrov{\'y}ch {\v c}i klecov{\'y}ch molekul, jejich vz{\'a}jemn{\'e} ovliv{\v n}ov{\'a}n{\'\i} i zp{\r u}soby, jak{\'y}mi se daj{\'\i} ukotovovat na kovov{\'e} povrchy, dovedl badatele k d{\r u}le{\v z}it{\'y}m nov{\'y}m poznatk{\r u}m, kter{\'e} letos v {\'u}noru publikoval presti{\v z}n{\'\i} odborn{\'y} {\v c}asopis ACS Nano.

}, keywords = {b{\'o}r, kank{\'a}n, karboran, klastr, klec, nanov{\v e}da, samo-organizace, spolupr{\'a}ce, v{\'y}zkum}, url = {http://pdf.avcr.cz/AB/2018-04/$\#$page=12}, author = {Jana Olivov{\'a}} } @article {148, title = {Architekti nejmen{\v s}{\'\i}ch stroj{\r u} (in Czech only)}, journal = {A / V{\v e}da a v{\'y}zkum}, volume = {04/2017}, year = {2017}, month = {December 6, 2017}, pages = {62-65}, type = {popular}, abstract = {

Zkoumaj{\'\i} nejkrajn{\v e}j{\v s}{\'\i} meze miniaturizace, sna{\v z}{\'\i} se proniknout do nanosv{\v e}ta jednotliv{\'y}ch atom{\r u}, c{\'\i}len{\v e} navrhovat a vytv{\'a}{\v r}et nov{\'e} molekuly s r{\r u}zn{\'y}mi funkcemi, sestavovat p{\v r}esn{\'e} nanostruktury slou{\v z}{\'\i}c{\'\i} jako nejmen{\v s}{\'\i} vyp{\'\i}na{\v c}e a motory. Kdo? Paul Weiss, Tom{\'a}{\v s} Ba{\v s}e a jejich {\v c}e{\v s}t{\'\i} i ameri{\v c}t{\'\i} kolegov{\'e}, kte{\v r}{\'\i} t{\v e}sn{\v e} prov{\'a}zali sv{\'e} v{\'y}zkumy.

}, keywords = {karborany, klastry, klece, monovrstvy, nanotechnologie, nanov{\v e}dy}, url = {http://pdf.avcr.cz/A/2017-04/$\#$page=63}, author = {Jana Olivov{\'a}} } @article {146, title = {Klastrov{\'e} molekuly na povr{\v s}{\'\i}ch substr{\'a}t{\r u} (in Czech only)}, journal = {Scientific American (Czech edition)}, volume = {kv{\v e}ten_2017}, year = {2017}, month = {05/2017}, pages = {34-35}, type = {popular}, keywords = {klastry, monovrstvy, povrchy, samo-organizace, slou{\v c}eniny b{\'o}ru}, url = {http://www.sciam.cz/files/UACH_5-2017_web.pdf}, author = {Tomas Base} } @article {142, title = {10-vertex closo-carborane: a unique ligand platform for porous coordination polymers}, journal = {CrystEngComm}, volume = {18}, year = {2016}, month = {06/2016}, pages = {2036-2040}, chapter = {2036}, abstract = {

1,10-dicarboxy-1,10-dicarba-closo-decaborane, a classical dicarboxylate spacer ligand type similar to the prototypal terephthalic acid, proved to be different not only from the latter, but also the closest relative, the 1,12-dicarboxy-closo-1,12-dicarbadecaborane regarding topology of the derived PCPs. Highly porous and robust compounds of zinc (rob net) and cobalt ({\textquoteright}quasi{\textquoteright} pcu) as well as a topologically unexpected copper compound (lvt) define the individuality of the 10-vertex carborane cage as a new fundamental spacer type in PCP chemistry. A combination of smaller sterics compared to the 12-vertex analogue, 45{\textdegree} preferred-orientation angle between the carboxylate planes and moderately low rotation barrier are held responsible for the uniqueness.

}, keywords = {10 vertex, carborane, Co, crystallography, Cu, MOF, porous coordination polymers, Zn}, doi = {10.1039/C5CE02501J}, url = {http://pubs.rsc.org/en/content/articlelanding/2016/ce/c5ce02501j$\#$!divAbstract}, author = {Ishtvan Boldog and Pablo J Bereciartua and Roman Bulanek and Monika Kucerakova and Marketa Tomandlova and Michal Dusek and Jan Machacek and Dirk De Vos and Tomas Base} } @article {141, title = {Adsorption of oriented carborane dipoles on a silver surface}, journal = {Physica Status Solidi B}, volume = {253}, year = {2016}, month = {10 DEC 2015}, pages = {591-600}, abstract = {

Modification of surfaces with self-assembled mono-layers (SAMs) represents a powerful and innovative tool for adjusting physical and chemical properties of surfaces. The adsorption of isomeric molecules with relatively strong and oppositely oriented molecular dipoles, 1,2-(HS)2-1,2-C2B10H10 and 9,12-(HS)2-1,2-C2B10H10, on a flat silver surface is investigated in order to adjust its work function in a desired way. Time-offlight secondary ion mass spectroscopy (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) are used to prove that both isomers (i) chemisorb on a silver surface as thiolates and (ii) exhibit comparable surface densities. Densely packed surfaces of both SAMs are additionally investigated by electrochemical impedance spectroscopy, and effective surface passivation is observed. Co-deposition of both derivatives is shown to enable effective and fine adjustment of the surface work function value within a range of 1V, which is confirmed by Kelvin probe force microscopy (KPFM). Experimental data indicate faster SAM formation for the former isomer. Contribution of the interface Ag{\textendash}S bonds to the work function changes is quantified.

}, keywords = {carborane, Kelvin probe force microscopy, self-assembled monolayers, silver, time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy}, doi = {10.1002/pssb.201552446}, author = {Aliaksei Vetushka and Laetitia Bernard and Olga Guseva and Zdenek Bastl and Ji{\v r}{\'\i} Plocek and Ivo Tomandl and Antonin Fejfar and Tomas Base and Patrik Schmutz} } @article {144, title = {Effizienter Korrosionsschutz von Silberoberfl{\"a}chen durch eine schonende und einfache molekulare Technologie}, journal = {Horizonte}, year = {2016}, month = {April 2016}, pages = {24-28}, abstract = {

Durch Korrosion entstehen der Volkswirtschaft gro{\ss}e Sch{\"a}den. Unf{\"a}lle durch verrostete Metallteile, Funktionsausf{\"a}lle in elektronischen Komponenten oder {\"a}sthetische Makel an Bau- und Kunstwerken sorgen nicht selten f{\"u}r juristischen Streit. Auch Korrosion von Silber ist ein weit bekanntes Ph{\"a}nomen. Wer kennt nicht schwarz angelaufenes Silberbesteck oder hat von ihm geh{\"o}rt? Dieser Artikel stellt eine seitens der Autoren unter Beteiligung von Bachelor-Absolventen k{\"u}rzlich entwickelte und an Industrieproben erfolgreich getestete Technologie eines neuartigen molekularen anorganischen Korrosionsschutzes f{\"u}r Silberoberfl{\"a}chen vor. Der neue Ansatz ist einfach und flexibel anwendbar und kann sehr schonend auf die Oberfl{\"a}chen appliziert werden. Dabei wird ein wirksamer Korrosionschutz erzeugt. Mehrere Eigenschaften dieses neuen Ansatzes f{\"u}r den Korrosionsschutz versilberter Oberfl{\"a}chen machen ihn einzigartig und in sehr vielen technischen und elektronischen Bereichen einsetzbar, z.B. in Teleskopspiegeln, {\"a}sthetischen Anwendungen oder zum Schutze historisch und kulturell interessanter Objekte. Die Entwicklung und Erforschung der neuen Technologie wurde durch ein bilaterales Austauschprogramm des Deutsch-Akademischen-Austauschdienstes (DAAD) und ein Erasmus+-Mobilit{\"a}tsprogramm gef{\"o}rdert.

}, keywords = {Korrozion, Silber, Technologie}, issn = {1432-9174}, url = {http://www.koord.hs-mannheim.de/deutsch/horizonte.html}, author = {Jorn F Lubben and Tomas Base} } @article {143, title = {Surface Dipole Control of Liquid Crystal Alignment}, journal = {JACS}, volume = {138}, year = {2016}, month = {April 19, 2016}, pages = {5957-5967}, chapter = {5957}, abstract = {

Detailed understanding and control of the intermolecular forces that govern molecular assembly are necessary to engineer structure and function at the nanoscale. Liquid crystal (LC) assembly is exceptionally sensitive to surface properties, capable of transducing nanoscale intermolecular interactions into a macroscopic optical readout. Self-assembled monolayers (SAMs) modify surface interactions and are known to influence LC alignment. Here, we exploit the different dipole magnitudes and orientations of carboranethiol and dithiol positional isomers to deconvolve the influence of SAM-LC dipolar coupling from variations in molecular geometry, tilt, and order. Director orientations and anchoring energies are measured for LC cells employing various carboranethiol and dithiol isomer alignment layers. The normal component of the molecular dipole in the SAM, toward or away from the underlying substrate, was found to determine the in-plane LC director orientation relative to the anisotropy axis of the surface. By using LC alignment as a probe of interaction strength, we elucidate the role of dipolar coupling of molecular monolayers to their environment in determining molecular orientations. We apply this understanding to advance the engineering of molecular interactions at the nanoscale.

}, keywords = {carborane, Dipole, liquid crystal, surface}, doi = {10.1021/jacs.6b02026}, url = {http://pubs.acs.org/doi/abs/10.1021/jacs.6b02026}, author = {Jeffrey J Schwartz and Alexandra M. Mendoza and Natcha Wattanatorn and Yuxi Zhao and Vinh T Nguyen and Alexander M Spokoyny and Chad A Mirkin and Tomas Base and Paul S Weiss} } @article {147, title = {Ve znamen{\'\i} boru. Funkcionalizace kovov{\'y}ch povrch{\r u}}, journal = {Scientific American (Czech edition)}, volume = {kv{\v e}ten_2016}, year = {2016}, month = {05/2016}, pages = {34-43}, type = {popular}, keywords = {b{\'o}r, funkcionalizace, kov, materi{\'a}l, povrch}, url = {http://www.sciam.cz/files/UACH_1.pdf}, author = {Tomas Base} } @article {139, title = {Self-Assembled p-Carborane Analog of p-Mercaptobenzoic Acid on Au{111}}, journal = {Chemistry of Materials}, year = {2015}, month = {06/2015}, type = {Article}, abstract = {

Thep-carborane cluster analog of p-mercaptobenzoic acid, 1

}, keywords = {boron compounds, carborane, crystallography, scanning tunneling microscopy, self-assembly}, doi = {10.1021/acs.chemmater.5b02263}, url = {http://pubs.acs.org/doi/pdf/10.1021/acs.chemmater.5b02263}, author = {John C Thomas and Ishtvan Boldog and Harsharn S Auluck and Pablo J Bereciartua and Michal Dusek and Jan Machacek and Zdenek Bastl and Paul S Weiss and Tomas Base} } @article {140, title = {Thermal isomerizations of monothiolated carboranes (HS)C2B10H11 and the solid-state investigation of 9-(HS)-1,2-C2B10H11 and 9-(HS)-1,7-C2B10H11}, journal = {Journal of Organometallic Chemistry}, year = {2015}, abstract = {

At 300-500 C, three C-thiolated closo-dicarbadodecaborane isomers 1-(HS)-1,2-C2B10H11 (1-o), 1-(HS)-1,7-C2B10H11 (1-m), and 1-(HS)-1,12-C2B10H11 (1-p), and two B-thiolated isomers 9-(HS)-1,7-C2B10H11 (9-m) and 9-(HS)-1,2-C2B10H11 (9-o) show two types of reaction: first, removal of an SH group from the closo-dicarbadodecaborane skeleton, and second, skeletal isomerizations from ortho to meta to para that lead to new isomers. A previously unreported SH skip from carbon-to-boron is also observed. The effect of the thiol group on the skeletal rearrangement is discussed. The isomerisation products are assigned on the basis of correlation of their computationally obtained dipole moments with their gas-chromatographic retention times. Computational results on molecular energies for the mono-thiolated species show good agreement between the calculated relative stabilities and the incidence and relative quantities of the isomerization products. Two of the starting B-thiolated isomers, 9-o and 9-m, were characterized using single-crystal X-ray diffraction analyses and their crystallographic packings as well as some selected structural parameters are discussed. All starting compounds were characterized using multinuclear NMR spectroscopy.

}, keywords = {carborane, Carboranethiol, closo-dicarbadodecaborane thiol, closo-dicarbadodecaboranes, Cluster, Dipole, Isomer, Isomerisation, Thermal Stability}, doi = {10.1016/j.jorganchem.2015.06.020}, url = {http://www.sciencedirect.com/science/article/pii/S0022328X15300462}, author = {Tomas Base and Jan Machacek and Zuzana Hajkova and Jens Langecker and John D Kennedy and Michael J Carr} } @article {138, title = {The gaseous structure of closo-9,12-(SH)2-1,2-C2B10H10, a modifier of gold surfaces, as determined using electron diffraction and computational methods}, journal = {Dalton Transactions}, volume = {42}, year = {2013}, chapter = {12015}, abstract = {

The molecular structure of closo-9,12-(SH)2-1,2-C2B10H10 has been determined by the concerted use of quantum chemical calculations and gas electron diffraction (GED). For the purposes of GED, the architecture of the carbaborane cage was simplified to allow it to have C2v symmetry, while the positioning of the thiol groups means that the molecule had overall C1 symmetry. The accuracy of the experimental structure, as well as that calculated at the MP2(full)/6-311++G(3df,3pd) level, has been gauged by comparison of experimental 11B NMR chemical shifts with those calculated using gauge-invariant atomic orbitals (GIAO) methods. The inclusion of electron correlation in the magnetic property calculations (GIAO-MP2) gave superior results to those carried out using GIAO-HF. The electronic structure of this derivative, with respect to its directional interaction with a metal surface, is outlined.

}, doi = {10.1039/c3dt51393a}, url = {http://pubs.rsc.org/en/results?artrefjournalname=dalton\%20trans.\&artrefstartpage=12015\&artrefvolumeyear=2013\&fcategory=journal}, author = {Derek A Wann and Paul D Lane and Heather E Robertson and Tomas Base and Drahomir Hnyk} } @article {120, title = {Carbon-substituted 9,12-dimercapto-1,2-dicarba-closo-dodecaboranes via a 9,12-bis(methoxy-methylthio)-1,2-dicarba-closo-dodecaborane precursor}, journal = {Polyhedron}, volume = {45}, year = {2012}, chapter = {144}, doi = {10.1016/j.poly.2012.07.067}, url = {http://www.sciencedirect.com/science/article/pii/S0277538712005207}, author = {Jens Langecker and Karla Fejfarova and Michal Dusek and Daniel Rentsch and Tomas Base} } @article {122, title = {Carboranedithiols: Building Blocks for Self-Assembled Monolayers on Copper Surfaces}, journal = {Langmuir}, volume = {28}, year = {2012}, chapter = {12518}, abstract = {

Two different positional isomers of 1,2-dicarbacloso-dodecaboranedithiols, 1,2-(HS)2-1,2-C2B10H10 (1) and 9,12-(HS)2-1,2-C2B10H10 (2), have been investigated as cluster building blocks for self-assembled monolayers (SAMs) on copper surfaces. These two isomers represent a convenient system in which the attachment of SH groups at different positions on the skeleton affects their acidic character and thus also determines their reactivity with a copper surface. Isomer 1 exhibited etching of polycrystalline Cu films, and a detailed investigation of the experimental conditions showed that both the acidic character of SH groups and the presence of oxygen at the copper surface play crucial roles in how the surface reaction proceeds: whether toward a self-assembled monolayer or toward copper film etching. We found that each positional isomer requires completely different conditions for the preparation of a SAM on copper surfaces. Optimized conditions for the former isomer required the exposure of a freshly prepared Cu surface to vapor of 1 in vacuum, which avoided the presence of oxygen and moisture. Adsorption from a dichloromethane solution afforded a sparsely covered Cu(0) surface; isomer 1 effectively removes the surface copper(I) oxide, forming a soluble product, but apparently binds only weakly to the clean Cu(0) surface. In contrast, adsorption of the latter, less volatile isomer proceeded better from a dichloromethane solution than from the vapor phase. Isomer 2 was even able to densely cover the copper surface cleaned up by the dichloromethane solution of 1. Both isomers exhibited high capacity to remove oxygen atoms from the surface copper(I) oxide that forms immediately after the exposure of freshly prepared copper films to ambient atmosphere. Isomer 2 showed suppression of Cu film oxidation. A number of methods including X-ray photoelectron spectroscopy (XPS), X-ray Rutherford back scattering (RBS), proton-induced X-ray emission (PIXE) analysis, atomic force microscopy (AFM), cyclic voltammetry, and contact angle measurements were used to investigate the experimental conditions for the preparation of SAMs of both positional isomers on copper surfaces and to shed light on the interaction between these molecules and a polycrystalline copper surface.

}, doi = {10.1021/la302334x}, url = {http://pubs.acs.org/doi/abs/10.1021\%2Fla302334x}, author = {Tomas Base and Zdenek Bastl and Vladimir Havranek and Jan Machacek and Jens Langecker and Vaclav Malina} } @proceedings {136, title = {Carboranethiols: Building Blocks for Self-Assembled Monolayers on Copper Surfaces, or a Novel Class of Etchants?}, journal = {European Materials Research Society, Spring Meeting}, year = {2012}, publisher = {E-MRS}, address = {Strasbourg, France, 2012 May 14-18}, abstract = {

This contribution aims at showing an unprecedented behavior of carboranedithiols on copper surfaces. Two different positional isomers of 1,2-dicarba-closo-dodecaborane-dithiol, 1,2-(HS)2-1,2-C2B10H10 (1) and 9,12-(HS)2-1,2-C2B10H10 (2), have been used as a convenient molecular system in which the attachment of -SH groups at different positions on the skeleton affects their acidic character and thus determines their reactivity with a copper surface. While the latter isomer represents a weak acid and forms a self-assembled monolayer (SAM) similarly to various aliphatic and aromatic thiols reported previously, the former isomer shows etching of copper leading to a complete dissolution of the films used in our experiments at a rate of approx. 70 nm per hour (in 7.5 mM EtOH solution of 1 at 20 C). A detailed investigation of the experimental conditions showed that the acidic character of -SH groups and the presence of oxygen at the copper surface play crucial role in how the surface reaction proceeds: whether towards the formation of a 1-SAM or towards etching and dissolution of a copper film. Reaction between 1 and a freshly prepared copper surface in vacuum or in a dry and oxygen-free solvent such as toluene, or dichloromethane yields a 1-SAM. This study shows the first thiol derivative that possesses the ability to etch copper films. A number of methods including XPS, RBS, PIXE have been used and the results will be presented and discussed. Acknowledgement: P205/10/0348, GACR

}, author = {Tomas Base and Zdenek Bastl and Vladimir Havranek and Jan Machacek and Vaclav Malina} } @article {119, title = {Decaborane Thiols as Building Blocks for Self-Assembled Monolayers on Metal Surfaces}, journal = {Inorganic Chemistry}, volume = {51}, year = {2012}, chapter = {1685}, abstract = {

Three nido-decaborane thiol cluster compounds, [1-(HS)-nido-B10H13] 1, [2-(HS)-nido-B10H13] 2, and [1,2-(HS)2-nido-B10H12] 3 have been characterized using NMR spectroscopy, single-crystal X-ray diffraction analysis, and quantum-chemical calculations. In the solid state, 1, 2, and 3 feature weak intermolecular hydrogen bonding between the sulfur atom and the relatively positive bridging hydrogen atoms on the open face of an adjacent cluster. Density functional theory (DFT) calculations show that the value of the interaction energy is approximately proportional to the number of hydrogen atoms involved in the interaction and that these values are consistent with a related bridging-hydrogen atom interaction calculated for a B18H22 C6H6 solvate. Self-assembled monolayers (SAMs) of 1, 2, and 3 on gold and silver surfaces have been prepared and characterized using X-ray photoelectron spectroscopy. The variations in the measured sulfur binding energies, as thiolates on the surface, correlate with the (CC2) calculated atomic charge for the relevant boron vertices and for the associated sulfur substituents for the parent B10H13(SH) compounds. The calculated charges also correlate with the measured and DFT-calculated thiol 1H chemical shifts. Wetting-angle measurements indicate that the hydrophilic open face of the cluster is directed upward from the substrate surface, allowing the bridging hydrogen atoms to exhibit a similar reactivity to that of the bulk compound. Thus, [PtMe2(PMe2Ph)2] reacts with the exposed and acidic B }, doi = {10.1021/ic202000b}, author = {Jonathan Bould and Jan Machacek and Michael G S Londesborough and Ramon Macias and John D Kennedy and Zdenek Bastl and Patrik Rupper and Tomas Base} } @article {121, title = {Nucleated Crystallization of Isotactic Polypropylene in Multilayered Sandwich Nanocomposites with Gold Particles}, journal = {Journal of Applied Polymer Science}, volume = {125}, year = {2012}, chapter = {4338}, doi = {10.1002/app.36589}, url = {http://onlinelibrary.wiley.com/doi/10.1002/app.36589/abstract}, author = {Miroslav Slouf and Antonin Sikora and Ewa Pavlova and Helena Vlkova and Josef Baldrian and Tomas Base and Ewa Piorkowska} } @article {123, title = {Reversible Capture of Small Molecules On Bimetallaborane Clusters: Synthesis, Structural Characterization, and Photophysical Aspects}, journal = {Inorganic Chemistry}, volume = {50}, year = {2011}, chapter = {7511}, doi = {10.1021/ic200374k}, url = {http://pubs.acs.org/doi/abs/10.1021\%2Fic200374k}, author = {Jonathan Bould and Tomas Base and Michael G S Londesborough and Luis A Oro and Ramon Macias and John D Kennedy and Pavel Kubat and Marcel Fuciman and Tomas Polivka and Kamil Lang} } @proceedings {135, title = {Self-assembled monolayers of polyhedral dicarbadodecaborane dithiols: a computational assesment of high coverage patterns}, journal = {18th Interdisciplinary Surface Science Conference (ISSC-18)}, year = {2011}, publisher = {Institute of Physics, Organised by the IOP Thin Films and Surfaces Group}, address = {Warwick University, UK}, abstract = {

During the last decade, carborane thiols were introduced as building blocks for self-assembled monolayers on metal surfaces.[1, 2, 3] This work follows up the first calculations of dicarbadodecaborane dithiolate moieties on gold under sparse coverage.[4] Their results were used to place the polyhedral dithiolate moieties on a (111) gold surface as densely as possible, that is one moiety over six surface gold atoms, and compare computationally their various possible arrangements by DFT calculations of periodical systems using the Abinit program.[5] The
intermolecular interactions force the moieties to deviate from the bonding geometry found under sparse coverage, the two sulfur atoms are now positioned at almost equal height over the surface. The calculated stability of the monolayer formed by 9,12-dithiolate is again significantly higher than that of the layer build from 1,2-dithiolate moieties.

[1] T. Base, Z. Bastl, Z. Plzak, T. Grygar, J. Plesek, M. Carr, V. Malina, J. Subrt, J. Bohacek, E. Vecernikova, O. Kriz, Langmuir 21 (2005) 7776-7785.
[2] T. Base, Z. Bastl, V. Havr }, url = {http://www.iop.org/conferences}, author = {Jan Machacek} } @article {118, title = {Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles}, journal = {Journal of Colloid and Interface Science}, volume = {354}, year = {2011}, chapter = {168}, abstract = {

Two selected carboranethiol isomers were used to modify flat silver surfaces. Both isomers, 1,2-(HS)2 }, doi = {10.1016/j.jcis.2010.10.052}, url = {http://www.sciencedirect.com/science/article/pii/S0021979710012385}, author = {Jorn F Lubben and Tomas Base and Patrick Rupper and Tina Kunniger and Jan Machacek and Sebastien Guimond} } @article {117, title = {Carborane-thiol-silver interactions. A comparative study of the molecular protection of silver surfaces}, journal = {Surface and Coatings Technology}, volume = {204}, year = {2010}, chapter = {2639}, abstract = {

The interaction between flat silver surfaces and carboranethiol derivatives, and its relevance regarding the molecular protection of silver against corrosion by hydrogen sulphide, are reported here. A comparison of the protective qualities of four carboranethiols (1-HS-1,2-C2B10H11, 1,2-(HS)2-1,2-C2B10H10, 9,12-(HS)2-1,2-C2B10H10, and 1,12-(HS)2-1,2-C2B10H10) with several organic thiols (1-butanethiol, 1-octanethiol, 1-dodecanethiol, benzene-1,2-dithiol, benzenethiol, and sodium 2-mercaptoethanesulphonate) is provided. All these derivatives are categorized according to their capacity to inhibit the interaction of silver with H2S in the presence of water molecules in the gas phase. We found that significantly better molecular protection for silver surfaces is afforded by the carboranethiol derivatives, and, of these, 9,12-(HS)2-1,2-C2B10H10 proved to be particularly effective. The corrosion of silver by H2S is accompanied by well-defined colour changes from lustrous silver, through yellow, violet, blue, and finally to grey. This sequence has not been reported before and it is used in this study as a qualitative indicator of the extent of silver corrosion. Our results are supported by reflectance UV

}, doi = {10.1016/j.surfcoat.2010.02.019}, url = {http://www.sciencedirect.com/science/article/pii/S0257897210001106}, author = {Tomas Base and Zdenek Bastl and Vladimir Havranek and Kamil Lang and Jonathan Bould and Michael G S Londesborough and Jan Machacek and Jaromir Plesek} } @article {124, title = {An Experimental Solution to the "Missing Hydrogens" Question Surrounding the Macropolyhedral 19-Vertex Boron Hydride Monoanion [B19H22](-), a Simplification of Its Synthesis, and Its Use As an Intermediate in the First Example of syn-B18H22 to anti-B18H22}, journal = {Inorganic Chemistry}, volume = {49}, year = {2010}, chapter = {4092}, doi = {10.1021/IC901976y}, url = {http://pubs.acs.org/doi/abs/10.1021/ic901976y}, author = {Michael G S Londesborough and Jonathan Bould and Tomas Base and Drahomir Hnyk and Mario Bakardjiev and Josef Holub and Ivana Cisarova and John D Kennedy} } @article {129, title = {The adhesion and growth of vascular smooth muscle cells in cultures on carboranethiol-modified gold films}, journal = {Engineering of Biomaterials}, volume = {11}, year = {2008}, chapter = {117}, url = {http://neutron.ujf.cas.cz/vdg/LC06041/2008_W_Parizek_1.pdf}, author = {Martn Parize and Tomas Base and Michael G S Londesborough and Vera Lisa and Lucie Bacakova} } @article {130, title = {Chemie podivnych tvaru aneb Vylet do rise hydridu boru (in Czech)}, journal = {Vesmir}, volume = {87}, year = {2008}, month = {2008/11}, pages = {748-749}, type = {popular}, keywords = {b{\'o}r, klastr, klec, molekula, monovrstva, nanovrstva, samo-organizace, uhl{\'\i}k}, issn = {1214-4029}, url = {http://casopis.vesmir.cz/clanky/clanek/id/8022}, author = {Tomas Base and Michael G S Londesborough} } @proceedings {128, title = {A comparison of boron hydride- and hydrocarbon-based thiol derivatives assembled on gold surfaces}, journal = {NSTI Nanotechnology Conference and Trade Show}, volume = {1}, year = {2008}, publisher = {NSTI}, address = {Boston, USA}, issn = {978-1-4200-8503-7}, url = {http://www.nsti.org/procs/Nanotech2008v1/2/T35.902}, author = {Tomas Base and Zdenek Bastl and Michael G S Londesborough and Jan Machacek} } @article {116, title = {Gold Micrometer Crystals Modified with Carboranethiol Derivatives}, journal = {J. Phys. Chem. C}, volume = {112}, year = {2008}, chapter = {14446}, abstract = {

The preparation and characterization of micrometer gold and silver single-crystals of well-defined shapes are reported here. The shapes of the crystals can be described as plates, polyhedra, and wires. The orientation of the crystal faces was studied using electron and X-ray powder diffraction techniques, and a (111) orientation of the large faces of gold plates was experimentally shown. The surface morphology of the crystal faces was studied by atomic force microscopy. Modifications of gold microplates with the thiolated carborane clusters 1,2-(HS)2-1,2-C2B10H10 (1), 9,12-(HS)2-1,2-C2B10H10 (2), and 1,12-(HS)2-1,12-C2B10H10 (3) are described. The carboranethiol molecules 1 and 2 show dipole moments of 4.1 and 5.9 D. In comparison, the thiolate derivative of compound 1 has a dipole moment of 4.7 D in the opposite direction to 1, and the thiolate form of compound 2 has a dipole moment of 16.7 D in the same direction. On the basis of X-ray photoelectron spectroscopy (XPS) analyses and values of work functions, we revealed that the molecules of 1 and 2 attached to the gold surface have similar electron distribution and dipole moments as within the free thiol derivatives. Following the modification of microplate gold crystals with 3, a monolayer of gold nanoparticles was attached on top of the carborane moieties. The composition of the surface species was studied using XPS. Dynamic contact angles of water on the modified gold surfaces are also discussed.

}, doi = {10.1021/jp802281s}, url = {http://pubs.acs.org/doi/abs/10.1021/jp802281s}, author = {Tomas Base and Zdenek Bastl and Miroslav Slouf and Mariana Klementova and Jan Subrt and Aliaksei Vetushka and Martin Ledinsky and Antonin Fejfar and Jan Machacek and Michael J Carr and Michael G S Londesborough} } @mastersthesis {131, title = {Carboranethiol-modified surfaces of gold colloids and films}, volume = {Ph.D.}, year = {2007}, month = {2007}, pages = {60}, school = {Institute of Chemical Technology}, address = {Prague}, author = {Tomas Base} } @proceedings {134, title = {Carborane Thiol-modified Gold Surfaces. A Study and Comparison of Modified Cluster and Flat Surfaces}, journal = {12th International Meeting on Boron Chemistry (IMEBORON-XII)}, year = {2005}, address = {Sendai, Japan, 11 }, author = {Tomas Base and Zdenek Bastl and Zbynek Plzak and Tomas Grygar and Jaromir Plesek and Michael J Carr} } @article {115, title = {Carboranethiol-Modified Gold Surfaces. A Study and Comparison of Modified Cluster and Flat Surfaces}, journal = {Langmuir}, volume = {21}, year = {2005}, chapter = {7776}, abstract = {

Four different carboranethiol derivatives were used to modify the surfaces of gold nanoparticles and flat gold films. The novel materials engendered from these modifications are extraordinarily stable species with surfaces that support self-assembled monolayers of 1-(HS)-1,2-C2B10H11, 1,2-(HS)2-1,2-C2B10H10, 1,12-(HS)2-1,12-C2B10H10, and 9,12-(HS)2-1,2-C2B10H10, respectively. Surprisingly, characterization of these materials revealed that a number of molecules of the carboranethiol derivatives are incorporated inside the nanoparticles. This structural feature was studied using a number of techniques, including X-ray photoelectron spectroscopy (XPS), UV }, doi = {10.1021/la051122d}, url = {http://pubs.acs.org/doi/abs/10.1021/la051122d}, author = {Tomas Base and Zdenek Bastl and Zbynek Plzak and Tomas Grygar and Jaromir Plesek and Michael J Carr and Vaclav Malina and Jan Subrt and Jaroslav Bohacek and Eva Vecernikova and Otomar Kriz} } @article {125, title = {Synthesis and catalytic activity of spaced ferrocene oxazolines}, journal = {Collection of Czechoslovak Chemical Communications}, volume = {68}, year = {2003}, chapter = {1206}, doi = {10.1135/cccc20031206}, url = {http://cccc.uochb.cas.cz/68/7/1206/}, author = {Petr Stepnicka and Tomas Base and Ivana Cisarova and Jiri Kubista and Stepan Vyskocil and Martin Sticha} } @article {126, title = {Acid-catalyzed self-alkylation of FcCH(2)NHPh. Solid-state structures of FcCH(2)NHPh and (FcCH(2))2NPh}, journal = {Inorganic Chemistry Communications}, volume = {5}, year = {2002}, chapter = {46}, doi = {10.1016/S1387-7003(01)00346-X }, url = {http://www.sciencedirect.com/science/article/pii/S138770030100346X}, author = {Tomas Base and Ivana Cisarova and Petr Stepnicka} } @article {127, title = {Preparation and structures of 1 {\textquoteright}-(diphenylphosphino)ferrocenecarboxaldehyde and {1 {\textquoteright}-(diphenylphosphino)ferrocenyl}methanol}, journal = {Inorganic Chemistry Communications}, volume = {4}, year = {2001}, chapter = {682}, doi = {10.1016/S1387-7003(01)00298-2}, url = {http://www.sciencedirect.com/science/article/pii/S1387700301002982}, author = {Petr Stepnicka and Tomas Base} } @article {160, title = {Carborane-thiol protected copper nanoclusters: Stimuli-responsive materials with tunable phosphorescence }, journal = {Chemical Science}, abstract = {

Atomically precise nanomaterials with tunable solid-state luminescence attract global interest. In this work, we present a new class of thermally stable isostructural tetranuclear copper nanoclusters (NCs), shortly Cu4@oCBT, Cu4@mCBT and Cu4@ICBT, protected by nearly isomeric carborane thiols: ortho-carborane-9-thiol, meta-carborane-9-thiol and ortho-carborane 12-iodo 9-thiol, respectively. They have a square planar Cu4 core and a butterfly-shaped Cu4S4 staple, which is appended with four respective carboranes. For Cu4@ICBT, strain generated by the bulky iodine substituents on the carboranes makes the Cu4S4 staple flatter in comparison to other clusters. High-resolution electrospray ionization mass spectrometry (HR ESI-MS) and collision energy-dependent fragmentation, along with other spectroscopic and microscopic studies confirm their molecular structure. Although none of these clusters show any visible luminescence in solution, bright μs-long phosphorescence is observed in their crystalline forms. The Cu4@oCBT and Cu4@mCBT NCs are green emitting with quantum yields (Ф) of 81 and 59 \%, respectively, whereas Cu4@ICBT is orange emitting with a Φ of 18 \%. Density functional theory (DFT) calculations reveal the nature of their respective electronic transitions. The green luminescence of Cu4@oCBT and Cu4@mCBT clusters get shifted to yellow after mechanical grinding, but it is regenerated after exposure to solvent vapour, whereas the orange emission of Cu4@ICBT is not affected by mechanical grinding. Structurally flatten Cu4@ICBT didn{\textquoteright}t show mechonoresponsive luminescence in contrast to other clusters, having bent Cu4S4 structures. Cu4@oCBT and Cu4@mCBT are thermally stable up to 400 {\textdegree}C. The Cu4@oCBT retained green emission even upon heating to 200 {\textdegree}C under ambient conditions, while Cu4@mCBT changed from green to yellow in the same window. This is the first report on structurally flexible carborane thiol appended Cu4 NCs having stimuli-responsive tunable solid-state phosphorescence.

}, keywords = {boron, carborane, Cluster, Copper, Phosphorescence, Responsive, thiol}, doi = {https://doi.org/10.1039/D2SC06578A}, url = {https://pubs.rsc.org/en/content/articlelanding/2023/sc/d2sc06578a}, author = {Arijit Jana and Madhuri Jash and Wakeel A Dar and Jayoti Roy and Papri Chakraborty and Paramasivam Ganesan and Sergei Lebedkin and Kaplan Kirakci and Sujan Manna and P. K. Sudhadevi Antharjanam and Jan Machacek and Monika Kucerakova and Sundargopal Ghosh and Kamil Lang and Manfred Kappes and Tomas Base and T. Pradeep} }