Luminescent organotin complexes with the ligand benzil bis(benzoylhydrazone)

Three organotin complexes have been synthesised by reaction of the ligand benzil bis(benzoylhydrazone) LH2 with SnR2Cl2 or SnR3Cl (R = Me, Bu, Ph). In all the compounds the ligand is doubly deprotonated and behaves as N2O2 tetradentate chelate, leading to distorted octahedral arrangements with the ligand in the equatorial plane and the organic groups in the axial positions. The complexes have been fully characterised by spectroscopic techniques including 13C and 119Sn NMR in solution and in the solid state, which confirm that the structure found in the solid state is retained in chloroform solution, and two of them by single crystal X-ray diffraction. The luminescent properties of the ligand and its complexes have also been tested as well as the effect of pH, the addition of acetone and the ionic strength over the luminescence intensity.