@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 {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 {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 {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 {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 {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} }