Synthesis and spectral studies on N,N,N',N'-tetramethylethylenediamine adducts of bis(4-methylpiperidinecarbodithioato- S,S')M(II) (M 5 zinc, cadmium): Single crystal X-ray structure of bis(4-methylpiperidinecarbodithioato-S,S') (N,N,N',N'-Tetramethylethylenediamine)zinc(II)

摘要

Bis(4-methylpiperidinecarbodithioato-S,S')(N,N, N',N'- tetramethylethylenediamine)zinc(II), [Zn(4-mpipdtc)_2 (TMED)] (1) and bis(4-methylpiperidinecarbodithioato-S,S') (N,N,N',N'- tetramethylethylenediamine)cadmium(II), [Cd (4-mpipdtc)2(TMED)] (2) adducts were synthesized and characterized by IR and NMR (~1H and ~(13)C) spectra. A single crystal X-ray structural analysis was carried out for complex 1. IR spectra of the complexes show the contribution of the thioureide form to the structures. Reduction in v_(C-N)(thioureide) for the adducts is attributed to the change in coordination number from four to six. In the ~(13)C NMR spectra, the downfield shift of NCS_2 carbon signal for 2 (205.20 ppm) from the chemical shift value of 1 (202.05 ppm) in due to large size of cadmium ion in 2 experiences less steric effect involved in transformation from tetrahetral to octahedral. Single crystal X-ray structural analysis of 1 showed that zinc is in a distorted octahedral environment with a ZnS_4N_2 chromophore. The Zn-S distances in 1 are longer than those in parent [Zn(4-mpipdtc)_2]. The acceptance of an additional neutral ligand by the [Zn(4-mpipdtc)_2] to form an octahedral adduct causes an increase in the Zn-S bond lengths and a consequent lowering of the S-Zn-S bite angle. The piperidine ring in the dithiocarbamate fragment is in the normal chair conformation.