Syntheses and structural characterization of new dithiophosphinato cadmium complexes

Abstract

New cadmium complexes of 4-methoxyphenyl dithiophosphinic acids, H 3 CO-C 6 H 4-(R)PS 2 Hwere prepared. The five dithiophosphinato ligands (L) involved were of the general structure H 3 CO-C 6 H 4-(R)PS − 2 with R= 3-methylbutyl, (L1); n-butyl, (L2); 2-methylpropyl, (L3); 1-methylpropyl, (L4) and 2-propyl, (L5). To the best of our knowledge, this is the first report on the preparation and characterization of the n-butylderivative. The acid forms of the ligands were obtained by treatment of the Lawesson reagent, (LR) [2,4-bis(4methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide] with the corresponding Grignard reagent in dry diethylether. The acids formed were transformed into easily crystallizable ammonium salts (NH 4 L) for purification. These salts were treated with CdCl 2 in ethanol at room temperature to produce the bis-dithiophosphinato cadmium complexes ([Cd(L) 2 ] 2) exclusively. The structures of the complexes were elucidated by elemental analysis, MS, FTIR and Raman spectroscopy techniques as well as 1 H-, 13 C-and 31 P-NMR. The crystal structures of [Cd(L1) 2 ] 2 and [Cd(L2) 2 ] 2 were also studied as examples. X-ray studies confirmed the nonplanar, fourcoordination geometry of the complexes and indicate that electron delocalization prevails in the PS − 2 moiety of the dithiophosphinato groups.