Thermal transformations of B10H12(NH3)2, B10H12(C5H5N)2, and B10H12(C9H7N)2

Conclusions For B₁₀H₁₂L₂, where L=NH₃, C₅H₅N, or C₉H₇N, features of thermal transformations in the range 25–850°C and the composition of the pyrolysis products are determined. The latter are x-ray amorphous phases, containing nitride, carbide, boron carbide, boron, and carbon.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2481–2484, November, 1988.     

The nature of the chemical bond in borazine (B3N3H6), boroxine (B3O3H3), carborazine (B2N2C2H6), and related species

The bonding problem in borazine (B₃N₃H₆), boroxine (B₃O₃H₃), and carborazine (B₂N₂C₂H₆) is successfully addressed through the consideration of the excited states of the constituent fragments, namely BH( ), NH( ), and CH( ). We propose the participation of resonant structures for all three species that help to explain the experimental findings. A discussion on the chemical pattern of the parental molecule benzene (C₆H₆) helps to make coherent the whole bonding analysis on the titled species.     

The structures of MeP(C2B10H10)2CH2 and MeAs(C2B10H10)2, compounds containing o-carborane ring carbon atoms in the heterocycle

Conclusions Crystal and molecular structures have been determined for 1-methylphospha-2,3,5,6-bis-o-carboranocyclohexane and 1-methylarsa-2,3,4,5-bis-o-carboranocyclopentane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1523–1528, July, 1979.     

Crystal structure of di (1-n-dodecylpyridine) decahydro-closo-decaborate(2-) (C5H5N-C12H25)2[B10H10]

Using X-ray analysis, we have determined the crystal structure of di(1-n-dodecylpyridine) decahydrocloso-decaborate(2-), (py-C₁₂H₂₅)₂[B₁₀H₁₀] (I), a yellow salt-like substance obtained by reaction of (py-C₁₂H₂₅)Br and K₂[B₁₀H₁₀] in an aqueous solution. Compound I melts at 125⁰ without decomposition and luminesces under ultraviolet radiation (λ_max=555 nm at 298 K). In I, quaternary pyridine bases, containing a hydrocarbon radical with the C₁₂ chain, are combined with the closo-cluster hydroborate anion [B₁₀H₁₀]^2-. This results in a charge transfer structure having shortened nonvalent (equatorial B) H.…H(C of pyridine) contacts of 2.41(8) Å. Crystals I are orthorhombic with a=8.584 (1), b=7.739(1), c=31.183(5) Å, V_cell=2071.4(5) ų, space group Pnmm, Z=2, d_calc=0.986 g/cm³ (a Syntex P2₁ automatic diffractometer, λCUK_α, N_msd/used=1654/711, R_aniso=0.076, R_w=0.080, w=1/(σ(F_obs)²+0.0007·F _obs ² ). Substantial changes are observed in the vibration range of the valent B?H bonds in the IR spectrum of I as compared to that of pure ionic K₂[B₁₀H₁₀], confirming the interaction.     

Triple linking of the decaboranyl cluster. Structure of [(SMe2)2B10H10(B10H13)2] as determined by synchrotron X-ray diffraction analysis

In an attempt to find generic routes to multiple inter-cluster sigma-linking, mild thermolysis of [6,9-(SMe2)2-arachno-B10H12] 1 in inert hydrocarbon solution gives the tridecaboranyl species [6,9-(SMe2)2-arachno-B10H(10)-1,5-(6'-nido-B10H13)2] 3 (23%).     

Quenched gas-phase reactions of tetraborane(10), B4H10, with substituted alkynes: new nido-dicarbapentaboranes and arachno-monocarbapentaboranes

New alkyl derivatives of the nido-dicarbapentaborane, 1,2-C(2)B(3)H(7), and arachno-carbapentaborane, 1-CB(4)H(10), have been identified as the main volatile carbaborane products in quenched gas-phase reactions of tetraborane(10), B(4)H(10), with alkyl-substituted ethynes RC[triple bond]CR' (R = Me, Et, (n)Pr or (t)Bu, R' = H; R = Me or Et, R' = Me). The gaseous mixtures were heated at 70 degrees C, and monitored by gas-phase mass spectrometry. Each reaction was quenched when the ethyne was used up. The quenched gas-phase reaction of B(4)H(10) and Me(3)SiC[triple bond]CH gave a single volatile carbaborane product, 1-Me(3)Si-1,2-C(2)B(3)H(6).     

Unexpectedly facile isomerisation of [7,10-Ph2-7,10-nido-C2B10H10]2- to [7,9-Ph2-7,9-nido-C2B10H10]2-

The 2e-reduction of 1,12-Ph2-1,12-closo-C(2)B(10)H(10) followed by oxidation or metallation gives products that arise from [7,9-Ph2-7,9-nido-C(2)B(10)H(10)](2-), formed by unexpectedly facile isomerisation of the kinetic 7,10-isomer: the 4,1,6-MC(2)B(10) compounds which result are progressively isomerised to 4,1,8- and 4,1,12-isomers for M = {CpCo} but to an equilibrium mixture of 4,1,8- and 4,1,12-isomers for M = {(arene)Ru}.