CHARGE DISTRIBUTION AND NUCLEOPHILIC REACTIVITY IN SULFUR LIGAND CHELATES . DIALKYL DERIVATIVES OF NICKEL(2) PALLADIUM(2) AND PLATINUM(2) BIS(CIS)ETHYLENEDITHIOLATES

Model calculations of the charge distribution in the species NiS4R40,-,2- indicate a considerable localization of charge on the four sulfur atoms in the dianion. In accord with this result, it is demonstrated that the sulfur atoms in Ni(II), Pd(II), and Pt(II) bis(cis)ethylenedithiolato dianions possess nucleophilic character. On reaction with alkylating agents, new, neutral, diamagnetic complexes of composition M(R22S4C4R4) were obtained which are shown to be the 1,4-S-bisdialkyl derivatives. The complexes are remarkably resistant to acids and bases and show no tendency to undergo reversible oxidation-reduction. The electronic spectra resemble those of the MS4C4R42- systems in agreement with the proposed planar structure. The complex with M = Ni, R′ = CH2C6H5, and R = C6H5 is debenzylated on irradiation with visible light. Some of the previously described adducts of the neutral group VIII metal dithienes, MS4C4R4, with olefins are proposed to be Diels-Alder adducts and are probably related to the new complexes. Preliminary experiments indicate that the dianions MSeCePhe2-(M = V, Mo, or W) undergo 1,4-S-dialkylation followed by decomposition. © 1968, American Chemical Society. All rights reserved.