Homobimetallic complexes containing Sn(IV) with acetylene dicarboxylic acid: their syntheses and structural interpretation by spectroscopic,semi-empirical,and DFT techniques

Homobimetallic carboxylates with general formulae (R₃Sn)_2?L (where R?=?Me, n‐Bu, Ph and L?=?acetylene dicarboxylate dianion) have been synthesized by refluxing disodium salt of acetylene dicarboxylic acid with triorganotin chlorides in 1?:?2 (L?:?M) molar ratio in methanol under reflux. These complexes have been characterized by elemental analyses, FTIR, and multinuclear NMR (¹H, ¹³C) spectroscopies. DFT calculations have been performed for structural elucidation and results were compared with semi‐empirical data. FTIR data indicate bidentate chelation of the ligand with tin and the complexes exhibit five‐coordinate geometry in the solid state. Such coordination behavior is also supported by DFT and semi‐empirical studies. NMR data confirm four‐coordinate geometry in solution.