Complete electron-transfer series of the Pt-N2S2 type

Abstract

Reaction of 1-phenyl-4-mono-or disubstituted thiosemicarbazides with platinum(I1,IV) salts affords the diamagnetic intensely colored neutral complexes Pt(C6Hb,R,R'-atf)s (8, R = R' = CH3; R = H, R' = CeH5, tert-CaH~). The nature of these complexes has been elucidated by a combination of electrochemical, epr, and electronic spectral studies. They have been shown to be the central members of five-membered electron transfer series Pt(C8Ha,R,R'-atf)zz whose component species (z = 2 --, 1--, 0, 1+, 2 + ) are interrelated by one-electron-transfer reactions. Polarographic half-wave potentials in acetonitrile solution occur in the range of ca. -1.2 to +0.8 V vs. sce. Cyclic voltammetric studies of the Pt(CaH5,tert-C4Ho-atf)gz series indicate reversible behavior for the processes 2 -1 -, 1t 0, and 0 * 1+ a t scan rates of 0.1-10 V/sec. Electronic spectra of all five members of this series are reported together with epr data for the spin-doublet z = 1 -, 1 + members of all three series This study provides a detailed demonstration of the validity of the electron-transfer series concept as applied to planar complexes containing unsaturated five-membered chelate rings.

One‐Dimensional Inorganic Complexes

“…Metal-metal interactions may be possible in the solid statestructures of M(CO)z(GL)(M = Rh, Ir) where G L represents a monoanionic bidentate ligand of substituted acetylacetonates (24,54,56,57,270), /I-ketoiminates (55), topolones (3,24), imidazoles (408a), formazanes (408a), 8-hydroxyquinolines, (218,255,402), and Schiff bases (402, 408a) as well as other ligands containing the N and 0 donor atoms (3,41,441,442,443,512). Numerous additional square planar complexes withN4 (59,63,145,184,188,300,356,369,386,447) 02S2 (22a), or N2Sz (149,191,256,266,383) donor atoms have been prepared but have yet to be fully characterized. UnIess there is evidence for unusual metalmetal interactions and partial oxidation, low conductivity is anticipated.…”

Structural study of four complexes of the M-N2S2 type derived from diethylphenylazothioformamide and the metals palladium, platinum, copper and nickel

“…In particular, Holm and Bechgaard have investigated the structural and electronic properties of series of electron-transfer complexes of the type M-N 2 S z 2 (see Fig. 2; Holm et al, 1967;Forbes et al, 1971;Jensen et al, 1972;Bechgaard, 1973Bechgaard, , 1974Bechgaard, , 1977.…”

“…In this study we reconfirm both tetra-hedral structures, and we also identify the more conventional (square) planar structure of PdL 0 2 and PtL 0 2 that is usually found for Me-bis-dithiolene-like compounds (Eisenberg, 1970). Forbes et al (1971) have suggested a square-planar structure for the N,N-dimethylphenylazothioformamide platinum complexes.…”

The structures of methyl 3-phenyldithiocarbazate and its derivative, square-planar bis(methyl N'-phenyldiazenecarbodithioato-N',S)platinum

“…PtL 2 belongs to a series of electron-transfer complexes of the type PtN2S z as studied by Forbes, Gold & Holm (1971) and Jenson, Bechgaard & Pedersen (1972). It is distinctive because of its intense blue colour in solution, with an absorption band in the visible region (2 = 720 cm-~; e = 10 500).…”

“…N/ I j~ or as a Pt II complex, in terms of a valence-bond structure (Forbes et al, 1971): In an attempt to clarify the problem by means of a structural determination, the X-ray analysis of the PtL z complex has been undertaken, together with an analysis of the free ligand, LH z, for comparison.…”