Organotins as a Locking Agent in the Formation of Dinuclear Complexes

In this paper the synthesis and characterization of new heterobimetallic compounds with a ligand derived from diacetylpyridine, hydrazine and salicylaldehyde has been reported. The open end of the ligand was locked with R₂SnCl₂ followed by the insertion of a transition metal ion in the cavity thus formed by locking the ligand. These compounds are characterized by TGA/DSC, IR, ¹H and ¹³CNMR, electronic spectra, magnetic moment and conductivity measurements. The disappearance of ν(O–H) and appearance of ν(Sn–O) in the IR spectrum of the Sn(saldp)R₂ {where saldp = bis(salicylaldehydehydrazone)diacetylpyridine and R = –CH₃, –C₄H₉} suggests the complex formation with R₂SnCl₂. The IR spectra of the complexes exhibited a blue shift in ν(C=N) indicating coordination of the azomethine nitrogen. The complexes are non-electrolytes in DMSO. The ¹HNMR and ¹³CNMR spectra of the complexes are not much different from that of the free ligand except for the disappearance of the signal at 9 ppm due to phenolic protons. The methyl or butyl protons attached to the tin appear at their usual places. The TGA profile of the ligand and its mononuclear complexes exhibit a three-step pyrolysis, although the binuclear complexes decompose in two steps leaving behind tin oxide as the final product.