@article {171, title = {Cluster versus coordination: the chemistry of cyclopentadienyl titanium and vanadium complexes with B- and C-functionalized carborane-thiols, [C2B10H12-n(SH)n] (n = 2 or 3)}, journal = {Chemical Science}, year = {2025}, month = {07/2025}, type = {Full article}, abstract = {

A series of B- and C-functionalized di- and trithiol chelating o-carborane ligands have been employed to explore the coordination chemistry with cyclopentadienyl titanium and vanadium complexes. Treatment of [Cp*TiCl3] with [LiBH4{\textperiodcentered}THF], followed by thermolysis with a C-functionalized carborane-dithiol ligand [1,2-(SH)2-1,2-C2B10H10], yielded octacapped octahedral [(Cp*Ti)4{Ti(1,2-(S)2-1,2-C2B10H10)}23-S)63-O)2] (1) and hexacapped trigonal bipyramidal [(Cp*Ti)4{Ti(1,2-(S)2-1,2-C2B10H10)}(μ3-S)6] (2) clusters. One of the driving forces of these reactions is the cleavage of C{\textendash}S bonds of carborane-dithiols that resulted in sulfide ligands and subsequently generated clusters 1 and 2. In contrast, a similar reaction with a B-functionalized carborane-dithiol [9,12-(SH)2-1,2-C2B10H10] led to B{\textendash}B bond formation that yielded a κ2-hydridoborato complex, [(Cp*Ti){κ2-BH3(9,12-(S)2-1,2-C2B10H10)}] (3). To the best of our knowledge, complex 3 is the first example of a carborane-dithiol functionalized hydridoborato complex. Interestingly, when the reactions of [Cp*TiCl3] or [Cp2TiCl2] were carried out with a B-functionalized carborane-trithiol, [8,9,12-(SH)3-1,2-C2B10H9], they led to coordination complexes, [(Cp/Cp*Ti){8,9,12-(S)3-1,2-C2B10H9}] (Cp* (4a) and Cp (4b)). Similarly, when [(Cp*VCl2)3] was employed as a metal precursor, deboronation was observed at the icosahedral cage that resulted in a zwitterionic complex, [(Cp*V){1,5,6-(S)3-nido-7,8-C2B9H9}] (5). All the clusters have been characterized by NMR, IR, mass spectrometry, and X-ray diffraction analysis. Furthermore, the theoretical analyses provided valuable insights into the electronic structures of these unusual clusters.

}, doi = {https://doi.org/10.1039/D5SC03562G}, url = {https://pubs.rsc.org/en/content/articlelanding/2025/sc/d5sc03562g}, author = {Subhash Bairagi and Deepak Kumar Patel and Debipada Chatterjee and Monika Kucerakova and Jan Machacek and Tomas Base and Thalappil Pradeep and Sundargopal Ghosh} } @article {169, title = {Mechanochromic luminescence in copper nanoclusters: resolving structural transitions through microcrystal electron diffraction}, journal = {Chemical Communications}, year = {2025}, month = {06/2025}, type = {Communication}, abstract = {

MicroED reveals insights into mechanochromic luminescence in copper nanoclusters, demonstrating structural transitions from crystalline to amorphous state upon grinding, with restoration of crystallinity following solvent exposure. Luminescence switching occurs due to reversible amorphization-recrystallization rather than chemical changes, providing critical design principles for such stimuli-responsive materials.

}, keywords = {Carboranethiol, Cluster, crystals, Cu4, ED, electron diffraction, luminescence}, doi = {https://doi.org/10.1039/D5CC02594J}, url = {https://pubs.rsc.org/en/content/articlelanding/2025/cc/d5cc02594j}, author = {Harshita Nagar and Subrata Duary and Vivek Yadav and Amoghavarsha Ramachandra Kini and Sudhadevi Antharjanam and Tomas Base and Anirban Som and Brent L. Nannenga and Thalappil Pradeep} } @article {166, title = {Nanomechanical Investigations of Crystals of Copper Nanocluster Isomorphs: Enhanced Hardness of the Low-Density Analogue}, journal = {Chemistry of Materials}, year = {2025}, month = {01/2025}, type = {Full article}, abstract = {

Atomically precise cluster crystals, with constituent units composed of tens to hundreds of atoms, are important for the construction of miniaturized solid-state devices. Understanding the mechanical characteristics of such crystals is crucial for these applications. In this study, we focused on the nanomechanical properties of crystals of two isomorphic copper nanoclusters (Cu4L4), protected by ortho-carborane-9-thiol, Cu4(oCBT)4, and meta-carborane-9-thiol, Cu4(mCBT)4. These two clusters possess identical square planar Cu4 cores embedded in butterfly-shaped Cu4S4 staples. Load{\textendash}displacement measurements indicated that the crystals of Cu4(oCBT)4 (hardness of \~{}534.31 MPa) were harder than those of Cu4(mCBT)4 (hardness of \~{}335.49 MPa). Despite their lower density, crystals of Cu4(oCBT)4 demonstrated increased hardness, owing to the presence of locked slanted layers that efficiently interacted with each other through various short contact supramolecular interactions. During indentation studies, multiple {\textquotedblleft}pop-in{\textquotedblright} events were observed for the crystals of both clusters, suggesting the dislocation of molecular layers within the crystal lattice. Dynamic mechanical analysis conducted at different loading frequencies indicated that crystals of Cu4(oCBT)4 have a higher storage modulus than Cu4(mCBT)4. Both the crystals are thermally robust, as evident from thermogravimetric analysis and attenuated total reflection-IR analysis. Using density functional theory, we calculated Young{\textquoteright}s modulus (Er) for both crystals at 1 and 2\% strain and found that the high-density isomorph had a lower Er, consistent with experimental data showing Er of Cu4(oCBT)4 and Cu4(mCBT)4 to be 9.79 and 8.54 GPa, respectively. These findings highlight the significant role of subtle structural differences in governing the nanomechanical behavior of isomorphic cluster crystals, paving the way for their rational design in advanced solid-state device applications.

}, keywords = {carborane, Copper, indentation, nanocluster, nanomechanical, thiol, Young{\textquoteright}s modulus}, doi = {https://doi.org/10.1021/acs.chemmater.4c03265}, url = {https://pubs.acs.org/doi/10.1021/acs.chemmater.4c03265}, author = {Amoghavarsha R Kini and Sanghamitra Debta and Arijit Jana and C Aparna and Vivek Yadav and Nataliia Kusiak and Tomas Base and Umesh V Waghmare and Pijush Ghosh and Thalappil Pradeep} } @article {170, title = {A Silver-Chalcogenide Nanomaterial Enveloped with a Carborane-Thiolate Shell for the Electroreduction of CO2 to CO}, journal = {ACS Applied Nano Materials}, year = {2025}, month = {07/2025}, type = {Full article}, abstract = {

Electrocatalytic CO2 reduction using atomically precise nanomaterials has garnered significant research interest, owing to their controllable molecular structures. Here, we have synthesized an electrocatalyst composed of single crystals having a one-dimensional assembly of silver atoms bridged by sulfur atoms of meta-carborane-9-thiolates. The molecular structure of the framework was further characterized through high-resolution ESI-MS, which exhibited silver- and carborane-thiolate-containing ions originating from the fragmentation of the framework. This thermally stable solid acted as an efficient catalyst for the electrocatalytic conversion of CO2 to CO with a Faradaic efficiency of 85 {\textpm} 3\%. In situ Raman studies provided experimental verification of binding of CO2 to the framework. First-principles density functional theory calculations confirmed the feasible adsorption of CO2 with the Ag chains, highlighting its favorable interaction with the catalyst. Furthermore, free energy calculations revealed the rate-determining step of the conversion process to be the formation of *COOH. This study presents an efficient electrocatalyst featuring a one-dimensional silver-chalcogenide framework.

}, keywords = {silver chalcogenide CO2 reduction carborane thiol}, doi = {https://doi.org/10.1021/acsanm.5c01918}, url = {https://pubs.acs.org/doi/10.1021/acsanm.5c01918}, author = {Arijit Jana and Zhengyuan Li and Amoghavarsha Ramachandra Kini and Vivek Yadav and Akhil S Nair and Astrid Campos Mata and Jingjie Wu and Jan Machacek and Tomas Base and Biswarup Pathak and Soumyabrata Roy and Thalappil Pradeep} } @article {167, title = {Site-specific substitution in atomically precise carboranethiol-protected nanoclusters and concomitant changes in electronic properties}, journal = {Nature Communications}, volume = {16}, year = {2025}, month = {01/2025}, type = {Full article}, chapter = {1197}, abstract = {

We report the synthesis of [Ag17(o1-CBT)12]3- abbreviated as Ag17, a stable 8e$^{-}$ anionic cluster with a unique Ag@Ag12@Ag4 core-shell structure, where o1-CBT is ortho-carborane-1-thiol. By substituting Ag atoms with Au and/or Cu at specific sites we created isostructural clusters [AuAg16(o1-CBT)12]3- (AuAg16), [Ag13Cu4(o1-CBT)12]3- (Ag13Cu4) and [AuAg12Cu4(o1-CBT)12]3- (AuAg12Cu4). These substitutions make systematic modulation of their structural and electronic properties. We show that Au preferentially occupies the core, while Cu localizes in the tetrahedral shell, influencing stability and structural diversity of the clusters. The band gap expands systematically (2.09\ eV for Ag17 to 2.28\ eV for AuAg12Cu4), altering optical absorption and emission. Ultrafast optical measurements reveal longer excited-state lifetimes for Cu-containing clusters, highlighting the effect of heteroatom incorporation. These results demonstrate a tunable platform for designing nanoclusters with tailored electronic properties, with implications for optoelectronics and catalysis.

}, keywords = {Alloy, boron, carborane, Cluster, Copper, gold, luminescence, Metal, silver, Structure, thiol}, doi = {https://doi.org/10.1038/s41467-025-56385-w}, url = {https://www.nature.com/articles/s41467-025-56385-w}, author = {Vivek Yadav and Arijit Jana and Swetashree Acharya and Sami Malola and Harshita Nagar and Ankit Sharma and Amoghavarsha Ramachandra Kini and Sudhadevi Antharjanam and Jan Machacek and Kumaran Nair Valsala Devi Adarsh and Tomas Base and Hannu H{\"a}kkinen and Thalappil Pradeep} } @article {165, title = {Multicolor photoluminescence of Cu14 clusters modulated using surface ligands}, journal = {Chemical Science}, year = {2024}, month = {07/2024}, type = {Full article}, abstract = {

Copper nanoclusters exhibit unique structural features and their molecular assembly results in diverse photoluminescence properties. In this study, we present ligand-dependent multicolor luminescence observed in a Cu14 cluster, primarily protected by ortho-carborane-9,12-dithiol (o-CBDT), featuring an octahedral Cu6 inner kernel enveloped by eight isolated copper atoms. The outer layer of the metal kernel consists of six bidentate o-CBDT ligands, in which carborane backbones are connected through μ3-sulphide linkages. The initially prepared Cu14 cluster, solely protected by six o-CBDT ligands, did not crystallize in its native form. However, in the presence of N,N-dimethylformamide (DMF), the cluster crystallized along with six DMF molecules. Single-crystal X-ray diffraction (SCXRD) revealed that the DMF molecules were directly coordinated to six of the eight capping Cu atoms, while oxygen atoms were bound to the two remaining Cu apices in antipodal positions. Efficient tailoring of the cluster surface with DMF shifted its luminescence from yellow to bright red. Luminescence decay profiles showed fluorescence emission for these clusters, originating from the singlet states. Additionally, we synthesized microcrystalline fibers with a one-dimensional assembly of DMF-appended Cu14 clusters and bidentate DPPE linkers. These fibers exhibited bright greenish-yellow phosphorescence emission, originating from the triplet state, indicating the drastic surface tailoring effect of secondary ligands. Theoretical calculations provided insights into the electronic energy levels and associated electronic transitions for these clusters. This work demonstrated dynamic tuning of the emissive excited states of copper nanoclusters through the efficient engineering of ligands.

}, keywords = {carborane, Carboranethiol, Cluster, Copper, Cu14, luminescence, single-crystal, thiol}, doi = {https://doi.org/10.1039/D4SC01566E}, url = {https://pubs.rsc.org/en/content/articlelanding/2024/sc/d4sc01566e?fbclid=IwY2xjawEbPEpleHRuA2FlbQIxMAABHSdHrudEy8SHjsokfQULtsUmfvHic2gEFr4U065NwJ6qN1LFmIkYwaAntQ_aem_eQUA0V-1Rl2jNgjrSiijPw}, author = {Arijit Jana and Subrata Duary and Amitabha Das and Amoghavarsha Ramachandra Kini and Swetashree Acharya and Jan Machacek and Biswarup Pathak and Tomas Base and T. Pradeep} } @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 {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 {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 {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 {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}, volume = {798}, year = {2015}, month = {12/2015}, pages = {132-140}, type = {Full article}, chapter = {132}, 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 {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 {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} } @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 {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}, month = {03/2010}, pages = {4092{\textendash}4098}, type = {Full article}, chapter = {4092}, abstract = {

The macropolyhedral [B19H22]- monoanion 1 and the dianion [B19H21]2-2 are synthesized in consistent 86-92\% yields by the reaction of [PSH]+[syn-B18H21]- with BH3(SMe2) in 1,2-Cl2C2H4 at 72 {\textdegree}C. [{\textquoteleft}PS{\textquoteright} is an abbreviation for {\textquoteleft}Proton Sponge{\textquoteright}, 1,8-bis-(dimethylamino)naphthalene. {\textquoteleft}PSH{\textquoteright} is its protonated derivative.] The molecular structures of 1 and 2 were elucidated as their [PS{BH2}]+ and [PS{BH2}]2+ salts 1a and 2a by single-crystal X-ray diffraction studies, in which all atoms were located, and supported by mass spectrometric analyses together with calculations of the cluster molecular geometries (ab ignitio and/or DFT) and of 11B chemical shifts based on GIAO-DFT shielding tensors. Acidification of dianion 2 with CF3COOH in acetonitrile, H2SO4 in dichloromethane, or aqueous HCl results in the clean formation of the monoanion [B19H22]-1. Conversely, shaking a concentrated acetonitrile solution of 1 in 0.5 M aqueous NaOH cleanly yields the [B19H21]2- dianion 2. Reaction of a dichloromethane solution of 1 with a 36\% aqueous solution of HCHO in the presence of H2SO4 quantitatively converts 1 at room temperature to a 1:1 mixture of the syn- and anti-isomers of B18H22. This cluster dismantling process is the first example of a syn- to anti-B18H22 isomer conversion.

}, keywords = {anti-B18H22, conversion, macropolyhedral borane clusters, syn-B18H22}, doi = {https://doi.org/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 {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} } @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 {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} }