Nucleophilic Reactivity of 4,4′-Disubstituted Diphenyl Sulfides Towards trans-Dichlorobis(pyridine)platinum(II)

The kinetics of the reaction of trans-[PtCl 2 py 2 ] with a series of 4,4′-disubstituted diphenyl sulfides, XC 6 H 4 SC 6 H 4 Y, have been studied at 30° in methanol. A linear free energy correlation has been obtained between the logarithm of the second order rate constant and the sum of the Hammett substituent parameters for X and Y. This result is consistent with the notion that bond making is the driving force when divalent sulfur functions as a nucleophile towards platinum(II) substrates and is consistent with the inability of 4,4′-dinitrodiphenyl sulfide to coordinate to platinum(II).