PREPARATION AND NUCLEAR-MAGNETIC-RESONANCE CHARACTERIZATION OF N-BONDED COMPLEXES OF PLATINUM(II) WITH PHOSPHORUS-NITROGEN RINGS CONTAINING 3-COORDINATE CHALCOGENS - X-RAY STRUCTURE OF [PTCL2(PET3)]2(PH4P2N4SE2ET2)

The reaction of 1,5-Ph4P2N4S2Ph2 with [PtCl2(PEt3)]2 in chloroform at 60-degrees-C produces the 1:1 adduct trans-PtCl2(PEt3)(Ph4P2N4S2Ph2) in which the platinum is attached to a nitrogen atom on the basis of P-31 nmr spectroscopy. By contrast, the corresponding reactions of 1,5-Ph4P2N4Se2R2 (R = Me, Et, Ph) produce the 2:1 adducts [PtCl2(PEt3)]2(Ph4P2N4Se2R2) (7a, R = Me; 7b, R = Et; 7c, R = Ph) which have been characterized by H-1, P-31 and Se-77 nmr spectroscopy and, in the case of 7b, by X-ray crystallography. Crystals of 7b are monoclinic, space group C2/c, with a = 27.803(7) angstrom, b = 12.378(7) angstrom, c = 15.752(8) angstrom, beta = 115.49(2)-degrees, V = 4893(3) angstrom3, and Z = 4. The least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms converged at R = 0.037 and R(w) = 0.022. The platinum centres in 7b are attached to distal nitrogen atoms of the disordered P2N4Se2 ring. The reaction of the six-membered ring Ph4P2N3SPh with [PtCl2(PEt3)]2 in dichloromethane at 23-degrees-C occurs in a regiospecific manner to give the 1:1 adduct PtCl2(PEt3)(Ph4P2N3SPh) in which, on the basis of P-31 nmr spectroscopy, the platinum is coordinated to a nitrogen atom between phosphorus and sulfur.