Study of an interesting interplay between thiourea and 4,6-dimethylpyri-midine-2-thiol with palladium(II) phosphine substrate

Treatment of [PdCl2(dppe)] with one equivalent of thiourea yielded a partially substituted complex [PdCl(dppe) {SC(NH2)2}]Cl (1a) whereas the compound [Pd(dppe){SC(NH2)2}2]2+ (1b) was obtained on performing the same reaction with two equivalents of thiourea. The reaction between [PdCl2(dppe)] and two equivalents of the sodium salt of 4,6-dimethyl pyrimidine-2-thiol resulted a cis configured complex [Pd{2-SC4H(4,6-Me)2N2}2(dppe)] (2). In the same pattern the reaction of [PdCl2(dppe)] with 4,6-dimethylpyrimidine-2-thiol, triethyl amine and thiourea in 1:1:1 mol ratio afforded a mononuclear heteroleptic complex [Pd{2-SC4HN2(4,6-Me)2}(dppe)]{SC(NH2)2}]Cl (3). All the reported complexes were characterized by elemental ana-lyses, NMR (1H, 13C{1H},31P{1H}), IR, UV-vis spectroscopy. The molecular structure of complex [Pd{2-SC4HN2(4,6-Me)2}(dppe)]{SC(NH2)2}]Cl (3) was established through single crystal X-ray diffraction and showed the distorted square planar geometry around the palladium metal centre.

Automated summary

Treatment of [PdCl2(dppe)] with thiourea produced partially substituted complex [PdCl(dppe) {SC(NH2)2}]Cl (1a), and with two equivalents of thiourea yielded compound [Pd(dppe){SC(NH2)2}2]2+ (1b). Reaction between [PdCl2(dppe)] and sodium salt of 4,6-dimethylpyrimidine-2-thiol resulted in the formation of cis configured complex [Pd{2-SC4H(4,6-Me)2N2}2(dppe)] (2). The reaction of [PdCl2(dppe)] with 4,6-dimethylpyrimidine-2-thiol, triethyl amine, and thiourea in a 1:1:1 mol ratio afforded a mononuclear heteroleptic complex [Pd{2-SC4HN2(4,6-Me)2}(dppe)]{SC(NH2)2}]Cl (3). The structures of all complexes were characterized using various techniques including elemental analysis, NMR, IR, and UV-vis spectroscopy, with complex [Pd{2-SC4HN2(4,6-Me)2}(dppe)]{SC(NH2)2}]Cl (3) further confirmed by X-ray diffraction.