@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 {149, title = {Acid-Base Control of Valency within Carboranedithiol Self-Assembled Monolayers: Molecules Do the Can-Can}, journal = {ACS Nano}, volume = {12}, year = {2018}, month = {02/2018}, pages = {2211{\textendash}2221}, type = {Full paper}, chapter = {2211}, 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 {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 {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 {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} }