Syntheses, crystal structure and spectroscopic characterization of bis(dithiocarbimato)-nickel(II)-complexes: A new class of vulcanization accelerators

摘要

The compounds (Ph_4P)_2[Ni(RSO_2N=CS _2)_2] [Ph_4P~+ = tetraphenylphosphonium cation; R-CH3 (1b), CH_3CH_2 (2b), CH_3(CH _2J_3 (3b) and CH_3(CH_2J_7 (4b)] were synthesized by the reaction of RSO_2N= CS_2K _22H_2O (1a-4a) with NiCl_2SH_2O and Ph4PBr. The elemental analyses of C, H, N and Ni were consistent with the proposed formula for 1b-4b. The IR data were consistent with the formation of bis(dithiocarbimato)-nickel(II)-complexes. The NMR spectra showed the expected signals for the cation and the dithiocarbimate anionic complex in a 2:1 proportion. The compounds 2b and 3b were also characterized by X-ray diffraction techniques. Compounds 2b and 3b crystallize in the P2i/c and Pf space groups, respectively. The nickel(Il) ions are positioned in special positions being coordinated by four sulfur atoms of the dithiocarbimate moieties in a square planar environment The Ph4P* counter-ions enter the structure interstice performing weak C-H-O and C-H-S intermolecular interactions. The activity of compounds lb-4b in the vulcanization of the natural rubber was evaluated. These studies confirm that the bis(dithiocarbimato)-nickel(II)-complexes are new vulcanization accelerators worth of further investigation.