Exo-π-bonding to an ortho-carborane hypercarbon atom: systematic icosahedral cage distortions reflected in the structures of the fluoro-, hydroxy- and amino-carboranes, 1-X-2-Ph-1,2-C2B10H10 (X = F, OH or NH2) and related anions

The structures of derivatives of phenyl-ortho-carborane bearing on the second cage hypercarbon atom a pi-donor substituent (F, OH, O-, NH2, NH- and CH2-) were investigated by NMR, X-ray crystallography and computational studies. The molecular structures of these compounds, notably their cage C1-C2 distances and the orientations of their pi-donor substituents (OH, NH2, NH- and CH2-) show remarkable and systematic variations with the degree of exo pi-bonding, which varies as expected with the pi-donor characteristics of the substituent

Atmospheric pressure chemical vapour deposition of tin sulfide thin films

Tin sulfide thin films have been laid down on glass substrates by APCVD of tin tetrabromide with hydrogen sulfide. The temperature of the substrate was varied over the range 250 to 600 °C. Flow rates of hydrogen sulfide into the reactor were altered from 0.6 to 1.8 dm3 min-1. The films were characterised by glancing-angle X-ray diffraction, Raman microscopy, EDAX and SEM. It is evident that at substrate temperatures from 250 to 450 °C tin(IV) sulfide is deposited, whereas at temperatures in excess of 550 °C tin(II) sulfide is deposited. At intermediate temperatures mixed-valent Sn2S3 is formed

Sulfur, tin and gold derivatives of 1-(2′-pyridyl)-ortho-carborane, 1-R-2-X-1,2-C2B10H10 (R = 2′-pyridyl, X = SH, SnMe3 or AuPPh3)

Reaction of the lithium salt of 1-(2′-pyridyl)-ortho-carborane, Li[1-R-1,2-C2B10H10] (R = 2′-NC5H4), with sulfur, followed by hydrolysis, gave the mercapto-o-carborane, 1-R-2-SH-1,2-C2B10H10 which forms chiral crystals containing helical chains of molecules linked by intermolecular S–HN hydrogen bonds. The cage C(1)–C(2) and exo C(2)–S bond lengths (1.730(3) and 1.775(2) Å, respectively) are indicative of exo S[double bond, length as m-dash]C π bonding. The tin derivative 1-R-2-SnMe3-1,2-C2B10H10, prepared from Li[1-R-1,2-C2B10H10] and Me3SnCl, crystallises with no significant intermolecular interactions. The pyridyl group lies in the C(1)–C(2)–Sn plane, oriented to minimise the NSn distance (2.861(3) Å). The tin environment is distorted trigonal bipyramidal with axial N and Me. The gold derivative 1-R-2-AuPPh3-1,2-C2B10H10, prepared from Li[1-R-1,2-C2B10H10] and AuCl(PPh3), reveals no NAu interaction in its crystal structure

Intra- and inter-molecular carboranyl C-H center dot center dot center dot N hydrogen bonds in pyridyl-containing ortho-carboranes

Four C-substituted derivatives of ortho-carborane, 1-R-1,2-C2B10H11, where R = 2'-pyridyl (1), 2'-picolyl (2), 5'-bromo-2'-pyridyl (3) or 3'-pyridyl (4) have been prepared using adaptations of standard procedures, and structurally characterised by single crystal X-ray diffraction studies in an exploration of C-H...N hydrogen bonding effects involving their carborane CH units. Calculations at the MP2/6-31G* level of theory were used to assess the strength of the hydrogen bonding detected, and calculated NMR shifts at the GIAO-B3LYP/6-311G* level were compared with measured C-H shifts to show that intramolecular C-H...N hydrogen bonding persisted in solution in the case of compound 1. The value of IR C-H stretching frequencies for probing hydrogen bonding in these systems was also studied. An unsuccessful attempt to convert compound 3 into a macrocyclic species (C2B10H10C5H3N)(3) in which three ortho-carborane units are linked through 2,5-disubstituted pyridine rings is also described

Preparative and structural studies on sulfur-linked carborane icosahedra: 2-phenyl-ortho-carboranyl-sulfur systems (2-Ph-1,2-C2B10H10)(2)X (X = S, S-2 or SO), and ortho-carboran-di-yl systems (1,2-C2B10H10Y)(2) (Y = S or SO)

Details are reported of the preparation and X-ray structural characterisation of the new compounds (PhCbo)2X, where PhCbo = 2-Ph-1,2-C2B10H10 and X = S (1) or SO (3), prepared from PhCboLi and SCl2 or SOCl2 respectively, as well as the known compound with X = S2 (2). Hydrogen in the presence of palladium/carbon reduced (3) to (1). Features of their structures (exo C–S and cage C–C distances and substituent orientations) are consistent with significant exo Sdouble bond; length as m-dashC dative π-bonding from their sulfur atoms to the cage hypercarbon atoms and weak exo π-bonding from the phenyl groups. Attempts to prepare systems (CboY)2, in which two ortho-carboran-di-yl residues Cbo are linked through two bridging units Y (S, SO) are also reported, as are their calculated structures