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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 analogues 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 ± 0.4 Å 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.

Hydrogen-capturing membranes under standard atmospheric conditions have been prepared based on polyurethane (PUR) nanofibers modified by using Pd nanoparticles. Hydrogen sorption capacity achieved at room temperature and a pressure of 1 bar is 207.7 ml g−1 (1.9 wt%) and at 4 bar, it is 1173.3 ml g−1 (10.6 wt%), measured by the standard Pressure Decay (PD) method. An original method, the dynamic Gas Chromatography (dGC) method, has been developed for H2 sorption tests simulating conditions in a gas mixture stream. The comparison of both types of sorption tests is useful for practical use in selectively capturing H2 under real conditions. Desorption tests performed by the dGC method confirmed the reasonable stability of the content of captured hydrogen in the membrane at room temperature and normal atmospheric pressure. The membrane is self-supporting and air-permeable, allowing easy design of the functional unit. [ABSTRACT FROM AUTHOR]

The cobalt bis(dicarbollide) anion [(1,2-C2B9H11)2-3,3'-Co]- (1-) is an increasingly important building block for the design of new biologically active compounds. Here we report the reactions of lithiated 1- with N-(ω-bromoalkyl)phthalimides Br-(CH2)n-N(CO)2NC6H4 (where n = 1 to 3) that give a number of new compounds substituted at dicarbollide carbon atom positions. For n = 2 and 3, substitution of the cobalt bis(dicarbollide) anion is accompanied by cyclocondensation of the organic moieties to give polycyclic ring structures attached to the cage. Predominant products correspond to oxazolo[2,3-a]isoindol-5(9bH)-1,2,3-dihydro-9b-yl)-(1-cobalt(III) bis(1,2-dicarbollide)(1-) (2-) and 1-(2H-[1,3]-oxazino[2,3-a]isoindol-6(10bH)-1,3,4-dihydro-10b-yl)-(1-cobalt(III) bis(1,2-dicarbollide)(1-) (4-) ions with isoindolone functions containing either five- or six-membered lateral oxazine rings. Additionally, products (tetrahydro-2-benzo[4,5]furan-1(3H)-1-[3,3]-yl-)-1,1'-μ-cobalt(III) bis(1,2-dicarbollide)(1-) (3-) and (2-(azetidin-yl-carbonyl)benzoyl-)-1-cobalt(III) bis(1,2-dicarbollide)(1-) (5-) were isolated, which display unusual cyclic structures featuring a bicyclic benzofuranone ring attached in a bridging manner by a quarternary carbon to two skeletal carbon atoms and a ketobenzoic acid amide substituent with a side azetidine ring. However, in the case of n = 1, only the anticipated methylene amine derivative [(1-NH2CH2-1,2-C2B9H11)(1',2'-C2B9H11)2-3,3'-Co]- (6-) was isolated in low yield after cleavage of the phthalimide intermediate species. The molecular structures of all isolated cyclic products 2- to 5- were confirmed by single-crystal X-ray diffraction studies, and the structure of cobalt bis(dicarbollide)-1-CH2NH2 6- was delineated using density functional theory applied at BP86/AE1 level in combination with NMR spectroscopy. Thus, the synthetic method described herein presents a facile route to new cobalt bis(dicarbollide) derivatives substituted by polycyclic structural motifs with potential biological activity. [ABSTRACT FROM AUTHOR]

CA inhibitors: Human carbonic anhydrases (CAs) are diagnostic and therapeutic targets. Various carborane cages are shown to act as active-site-directed inhibitors, and substitution with a sulfamide group and other substituents leads to compounds with high selectivity towards the cancer-specific isozyme IX. Crystal structures of the carboranes in the active site provide information that can be applied to the structure-based design of specific inhibitors., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)