Some new pentacoordinated anionic spirobicyclic silicon(IV) compounds containing the isothiocyanato group, [(C₆H₄O₂)₂SiNCS]⁻ M⁺; [M=K(1), Na(2), K(18-crown-6)(3), NH₄(4)], have been prepared by the activation of the silicon centre of tetracoordinated silances by NCS⁻ ion. These compounds have been characterised by elemental analyses, IR, multinuclei (¹H,¹³C and²⁹Si) NMR and FAB mass spectroscopy. Synthesis of stable spirobicyclic hexacoordinated dianionic siliconates with six-and seven-membered oxygen-containing rings around silicon atoms, [(C₇H₄O₃)₂ Si(NCS)₂]²⁻2B⁺; (B=PyH(5), 3-mepyH(6)4-mePyH(7)] and [(C₈H₄O₄)₂Si(NCS)₂]²⁻2[3-mepyH]⁺(8), are also described. The complexes5–8 have been achieved from the reactions of appropriate cationic five-coordinate silicon (IV) intermediate with salicylic acid (5–7) or phthalic acid (8). The resulting compounds have been characterised by elemental analyses. IR multinuclei (¹H,¹³C,²⁹Si) NMR spectral data.

The scope of Wurtz coupling and catalytic dehydrocoupling methods for the synthesis of functional polysilanes of compositions, [RR'Si]$_n$ (linear), [(PhMeSi)$_x$-co-(RSi)$_{1−x}$]$_n$ (branched) and [RSi]$_n$ (network) [R = Et₃SiCH₂CH₂, 2-Fu/2-ThMe₂SiCH₂CH₂ (Fu = Furyl, Th = Thienyl), 𝑛-Hex or Ph; R' = H or Me] is presented. By virtue of 𝜎-delocalized silicon backbone and variable HOMO-LUMO band gap energies, these polymers are found to be promising candidates as reducing agents for Ag(I) ions in toluene/cyclo-hexane and provide a simple approach for ‘size-controlled’ synthesis of silver nanoparticles (AgNPs) as well as fluorescent polymer-silver nanocomposites.