Acid-catalysed hydrolysis of a series of dinitro-complexes of platinum(II)

Abstract

The acid-catalysed replacement of a nitro-group from the series of complexes cis- and trans-[PtA₂(NO₂)₂][where A = NH₃, PEt₃, SEt₂, pyridine, thiourea, and ½(2,2′-bipyridyl)] in aqueous solutions of sulphuric acid at 25° has been studied. At the acid concentrations employed (a) the relative ease of removal of the nitro-group for a given group A is cis > trans when A = PEt₃ or SEt₂ but trans > cis when A = pyridine or NH₃, and (b) the bipyridyl complex reacts faster than the dipyridine compound. The relative cis:trans rates are those expected for the groups A based on their trans-effects relative to that of the nitro-group. The mechanism of the reaction is discussed.