Synthesis and characterization of benzylselenolate complexes of palladium(II) and platinum(II)

Reactions of sodium benzylselenolate with several palladium(II) and platinum(II) complexes were carried out and a variety of products isolated and characterized. Reactions of Na2PdCl4 or K2PtCl4 with NaSeBz gave [M(SeBz)2]n (M=Pd or Pt; Bz=CH2Ph) which when treated with tertiary phosphines yielded [M(SeBz)2(L-L)]. The latter can also be prepared by the reaction of MCl2(L-L) (L-L=dppm, dppe or 2PPh3) with NaSeBz. Treatment of [M2X2(μ-Cl)2(PR3)2] with NaSeBz in 1:2 molar ratio afforded complexes of the type [M2X2(μ-SeBz)2(PR3)2] (M=Pd or Pt; X=Cl or Me; PR3=PEt3, PPrn3, PBun3, PMe2Ph, PMePh2 or PPh3) which existed predominantly as a cis isomer. Reaction of [M2Cl2(μ-Cl)2(PR3)2] with [M2Cl2(μ-SeBz)2(PR3)2] gave heterobridged complexes [M2Cl2(μ-Cl)(μ-SeBz)(PR3)2], the bridging chloride in the latter can be substituted with SBut or pz. All the complexes were characterized by elemental analysis and NMR (1H, 31P, 77Se, 195Pt) spectral data. Stereochemistry of these complexes has been discussed on the basis of NMR data. The crystal structure of [Pt2Cl2(μ-SeBz)2(PPrn3)2] has established a cis configuration with a bent four-membered Pt2Se2 ring. The complex [Pd(SeBz)2]n on thermolysis at 630°C yields Pd17Se15.