Influence of functionalities on the structure and luminescent properties of organotin(IV) dithiocarbamate complexes

Five neworganotin(IV) dithiocarbamate complexes of the form R2SnL2 (R = Bu-n, L = L1, (4-phenylpiperazine-1-dithiocarbamate) 1, L2, (N-benzyl-N'-methyl-4-pyridyldithiocarbamate) 2; Ph, L3, (N-benzyl-N'-methyl-3-pyridyldithiocarbamate) 3) and Ph3SnL (L = L4, (N, N'-di(methyl-3-pyridyldithiocarbamate)) 4, L5, (4ethoxycarbonylpiperidine-1-dithiocarbamate) 5) have been synthesized and characterized by elemental analysis, spectroscopy (IR, UVeVis., H-1, C-13 and Sn-119 NMR) and their structures have been investigated by single crystal X-ray crystallography. In (1,2) the structure has C-2 symmetry with the tin atom in a highly distorted octahedral six-coordinate geometry in which the bidentate ligands are asymmetrically bonded and the two Bu-n groups subtend an angle at the metal of 140.7(1), 141.4(3)degrees. By contrast 3, also with C-2 symmetry, with phenyl substituents, is closely octahedral. In 3 the Py(N) on the dtc backbone interacts with the H37 on the adjacent molecule via unconventional C-H center dot center dot N hydrogen bonding forming a six membered benzene like (C2H2N2) structure. In 4 and 5 five coordinate TBP geometry is established; 4 contains two molecules in the asymmetric unit (4A and 4B). In 4 the Py(N) on the dithiocarbamate unit uniquely interacts with the tin atom on the neighbouring molecule with Sn center dot center dot center dot N contacts at 3.11 angstrom. The C-H center dot center dot center dot pi(CG) interactions between CG of 4A and H34 of 4B are also observed. These interactions have been supported by theoretical calculations. All the complexes luminesce in CH2Cl2 solution at room temperature except for 1; the strongest luminescent behaviour is found in 4. TGA analysis of 3 and 5 show a double and single step decomposition respectively. (C) 2015 Elsevier B.V. All rights reserved.