Synthetic and structural aspects of certain diorganosilicon(IV) chelates derived from sterically demanding 4-(2 '-mercapto phenyl imino alkyl/aroyl)-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-ones

Diorganosilicon (IV) Schiff base chelates of the type RR'Si[R"C(:o-NC6H4S)C :C(O)N(C6H5)N:CCH3, have been synthesised by the reaction of diorganodichlo rosilanes, RR'SiCl2 where (i)R =R' = -CH3 (ii) R = -CH3 and R' = -C6H5 with the disodium salt of 4-(2'-mercapto phenyl imino alkyl/aroyl) - 2,4 - dihy dro-5-methyl - 2-phenyl-3H-pyrazol-3-ones i.e. R"C(:o-NC6H4SNa)C:C(ONa)N(C6 H5)N:CCH3 (where R" = -CH3, -C2H5 - C6H5 and - p - Cl C6H4) in benzene solu tion. These chelates may alternatively be prepared by the reaction of Schif f bases with the corresponding diorganodichlorosilanes in presence of triet hylamine in benzene solution in a 1:1:2 molar ratio. The compounds, thus ob tained, were characterised on the basis of molecular weight measurements, I R and H-1, C-13, Si-29 NMR spectral studies.