Synthesis and characterization of gallium-arsenic compounds containing a four-membered GaAsGaCl or GaAsGaAs ring: crystal structures of (Me3SiCH2)2GaAs(SiMe3)2Ga(CH2SiMe3)2Cl and [(Me3SiCH2)2GaAs(SiMe3)2]2

The third example of an organogallium four-membered ring compound with arsenic, halogen mixed bridging, (Me3SiCH2)2GaAs(SiMe3)2Ga(CH2SiMe3)2Cl (1), was prepared by the reaction of (Me3Si)3As (2) with two equivalents of (Me3SiCH2)2GaCl. X-ray crystallographic analysis showed that the compound contains a nonplanar GaAsGaCl ring. The crystals belong to the monoclinic system space group P21/c (C25h) with four molecules per unit cell of dimensions a 12.476(2), b 15.832(2), c 22.279(3) Å, β 108.87(1)°, V 4164(2) Å3. The dimer [(Me3SiCH2)2GaAs(SiMe3)2]2 (3) was prepared by reaction of LiAs(SiMe3)2 and (Me3SiCH2)2GaCl. Its solid-state dimeric structure was established by single-crystal X-ray analysis. Crystals of 3 belong to the orthorhombic system space group Pbcn (D142h) with four dimers in a unit cell of dimensions a 12.886(1), b 21.172(2), c 18.610(2) Å, V 5077(1) Å3. The centrosymmetric dimers contain a planar GaAsGaAs ring with GaAs bond lengths of 2.572(1) and 2.561(1) Å, and AsGaAs angles of 85.85(3) and 86.32(3), and GaAsGa 93.91(2)°. Compound 3 reacts with two equivalents of (Me3SiCH2)2GaCl to produce 1 as a minor product along with a mixture of other unidentified products. 1H and 13C{1H} NMR spectra of the product mixture obtained from the reaction of 3 with two equivalents of Ph2GaCl and that from the reaction of [Ph2GaAs(SiMe3)2]2 with two equivalents of (Me3SiCH2)2GaCl display some common signals, which are believed to be due to Ph2GaAs(SiMe3)2Ga(CH2SiMe3)2Cl. © 1991.

Duke Scholars

Author Andrew T. McPhail Chemistry