摘要：

Various types of palladium(II) complexes have been characterized with four polydentate ligands: diphenyl(o-methylthiophenyl)phosphine (SP), bis(o-methylthiophenyl)phenylphosphine (DSP), tris(o-methylthiophenyl)phosphine (TSP), and tris(o-methylthiophenyl)arsine (TSA). The planar complexes [Pd(SP)Cl2] and [Pd(SP)2](ClO4)2 are obtained with the ligand SP. Bis(o-methylthiophenyl)phenylphosphine functions as a bidentate ligand in [Pd(DSP)Cl2], but as a tridentate in [Pd(DSP)Cl]ClO4. The potentially tetradentate ligands TSP and TSA function only as bidentates in [Pd(TSA)Cl2] and [Pd(TSP)Cl2], but they function as tetradentates in the [Pd2(TSP)Cl4] and [Pd2(TSA)Cl4] complexes by coordinating to two different palladium ions. Both ligands form deeply colored bis complexes, [Pd(TSA)2](ClO4)2 and [Pd(TSP)2](ClO4)2, which exhibit electronic absorption spectra quite different from that of the colorless [Pd(SP)2](ClO4)2 complex. The behavior of palladium(II) toward these ligands is contrasted with that of nickel(II), which forms five-coordinate complexes with all three phosphorus-sulfur ligands.4-6 Also the failure of the sulfur-containing tetradentates TSP and TSA to form trigonal-bipyramidal complexes with palladium(II) is contrasted with the ready formation of such complexes by similar tetraarsine and tetraphosphine ligands.7.

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