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

• Five new organotin(IV) dithiocarbamates have been synthesized and characterized.
• The intermolecular non classical C–H⋯N hydrogen bonding is observed in 3.
• Complex 4 shows interesting intermolecular Sn…N and C–H … π(SnS2C) interactions.
• These interactions have been supported by theoretical calculations.
• The photoluminescent property of 1–5 and TGA of 3 and 5 have been investigated.

Five new organotin(IV) dithiocarbamate complexes of the form R2SnL2 (R = nBu, 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, (4-ethoxycarbonylpiperidine-1-dithiocarbamate) 5) have been synthesized and characterized by elemental analysis, spectroscopy (IR, UV–Vis., 1H, 13C and 119Sn NMR) and their structures have been investigated by single crystal X-ray crystallography. In (1,2) the structure has C2 symmetry with the tin atom in a highly distorted octahedral six-coordinate geometry in which the bidentate ligands are asymmetrically bonded and the two nBu groups subtend an angle at the metal of 140.7(1), 141.4(3)°. By contrast 3, also with C2 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⋯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⋯N contacts at 3.11 Å. The C–H⋯π (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.

Five new di and tri organotin(IV) dithiocarbamate complexes have been synthesized and fully characterised. X-ray crystallography revealed the rare intermolecular N⋯H–C (in 3), Sn⋯N and C–H … CG(SnS2C) (in 4) interactions. All the complexes except 1 show photoluminescence in CH2Cl2 solution. Thermal analysis of 3 and 5 have been carried out.Figure optionsDownload as PowerPoint slide