Aspects of the chemistry of metallacarboranes containing heavy main group elements

Abstract

The structural patterns of the dicarbollide, $[nido-C_2B_9H_{11}]^{2-}$(1) in many different classes of the transition and/or the main group element metallacarborane compounds are classified and discussed according to variable metal to ligand ratio. The foregoing overview reveals the paucity of $\sigma$-bonded heterocarboranes and the heavy main group element metallacarborane chemistry. particularly heterobimetallic systems, raising engaging questions as to the preparation of new types of metallacarboranes containing heavy main group elements. In this dissertation, the new synthetic routes to a wide range of novel carborane complexes of the heavy main group elements were devised and the full characterization including the molecular structure analyses and the physical property measurements were carried out. A set of new indacarboranes such as $[ClIn(THF)_x(C_2B_9H_{11}]$ (2), $[Cl_2In(THF) (C_2B_9H_{11})]^-$(3) and $[In(C_2B_9H_{11})_2]^{2-}$(4) has been prepared from the reac tion system of $Tl_2\cdot1$ and $InCl_3$ with variable stoichiometry. Reactios of 2 with bis(3,5-dimethylpyrazlyl)borate (BMPB) and tris (3, 5-dimethylpyrazolyl)borate (TMPB) afforded [In(BMPB) (pz) ($C_2B_9H_{11}$)] and [In (TMPB) ($C_2B_9H_{11}$)](5), respectively. Single crystal X-ray diffraction studies were performed on three compounds 3,4 and 5. The slip-distortion of In toward the symmetric boron atom of the $C_2B_3$ face of 1 is operative in all case, resulting in $\sigma$-bonding between In and $\eta^{-1}-C_2B_9$ cage in case of 5. The spectroscopic properties of these compounds and the reactivities of 2 and 3 are also discussed. The endo-$\sigma$-bonded metallacarboranes [10-endo-{$(\mu-H)MPh_3$}-7,8-nido-$C_2B_9H_{10}]^-$(M=Ge, Sn) have been prepared in high yields as $[Ir(CO) (MeCN)-(PPh_3)_2]^+$ salts by an equimolar reaction of $Ph_3MCl$ with $Tl_2\cdot1$ in MeCN. The molecular structure of both compounds have been determined by X-ray diffraction studies. The hydrolysis of 1-...