Dinuclear organotin(IV) complexes with bis-acyl-hydrazones containing flexible linker: Synthesis, spectroscopic investigation and crystal structure of dimethyl- and diphenyltin(IV) complexes with succinic dihydrazones

Four new dinuclear organotin(IV) complexes, (R2Sn)2La [R = Me (1), R = Ph (2)] and (R2Sn)2Lb [R = Me (3), R = Ph (4)], have been synthesized from the reaction of R2SnCl2 (R = Me or Ph) with bis(2-hydroxy-3-methoxybenzylidene)succinohydrazide (H4La) and bis(5-bromo-2-hydroxybenzylidene)succinohydrazide (H4Lb). The synthesized compounds have been investigated by elemental analysis, IR, 1H NMR, 13C NMR and 119Sn NMR spectroscopy. The results show the all complexes are dinuclear and two doubly deprotonated tridentate domain of the acyldihydrazone is coordinated to two SnR2 moieties via phenolic oxygen, imine nitrogen and enolic oxygen. The structures of 1 and 3 have been also confirmed by X-ray crystallography. Both complexes are centrosymmetry with the alkyl linker chain shows anti conformation. The intermolecular weak Sn⋯O bonds lead to 1D polymeric chain containing four-membered Sn2O2 planar rings. On the basis of 119Sn NMR data coordination number of tin is five in solution.