Organotin compounds bearing mesogenic sidechains: synthesis, x-ray structures and polymerisation chemistry

Organotin compounds R3Sn(CH2)(n+2)OC6H4C6H4Y (R-3 = Ph-3, Ph2Bu; Y = H, CN; n = 1-3) and RX2Sn(CH2)(n+2)OC6H4C6H4Y (R = Ph, Bu; Y = H, CN; X = Br, I; n = 1-3) have been synthesised and characterised by H-1-, C-13-, Sn-119-NMR and Mossbauer spectroscopies. X-ray crystallography reveals tetrahedral geometries for Ph3Sn(CH2)(4)OC6H4C6H5 and Ph3Sn(CH2)(3)OC6H4C6H4CN, a six-coordinated, bromine-bridged dimeric structure for PhBr2Sn(CH2)(3)OC6H4C6H5 containing a mer-Br3C2OSn coordination sphere about tin and a five-coordinated monomeric structure for PhBr2Sn(CH2)3OC6H4C6H4CN. In all cases there is strong alignment of mesogenic groups in the solid-state but only PhBr2Sn(CH2)(3)OC6H4C6H4CN shows any indication of liquid-crystal behaviour. Wurtz polymerisation of RBr2Sn(CH2)(5)OC6H4C6H5 (R = Ph, Bu), both of which contain non-chelating ether functions, generated polystannanes (RR'Sn)(n) with M-n 2.3 x 10(5); M-w 3.0 x 10(5); M-w/M-n 1.30 and M-n 1.3 x 10(5); M-w 2.5 x 10(5); M-w/M-n 1.96, respectively, while no polymer was obtained from chelated PhBr2Sn(CH2)(3)OC6H4C6H5 (C) 2003 Elsevier B.V. All rights reserved.