Reactivity of Chelated Dinuclear Platinum(ii) Complexes : The role of the diamine bridges on substitutional reactivity

The search for new Pt(II) metal drugs is underpinned by an in-depth understanding of the factors controlling the bio-reactivity of the Pt(II) pharmaceuticals. An emerging class of compounds which has shown improved antitumour activity is the multinuclear Pt(II) complexes, epitomized by the favourable reactivity profile of BBR3464 from Prof. Farrell's labs. Kinetic data of multinuclear Pt(II) compounds is not extensive. This book, reports the substitution reactions of bis(2-pyridylmethyl)amine-chelated dinuclear Pt(II) complexes linked by diamine bridges. The reactions were studied under pseudo first-order conditions as a function of concentration of nucleophiles and temperature using stopped-flow and UV-visible spectroscopic techniques. In general, the substitution of the coligand by the sulfur containing nucleophiles proceeds via a two-step reaction pathway which is associatively activated. In the studied sets of Pt(II) dinuclears, substitution of the coligands is controlled mainly by steric effects, derived from the molecular conformations of the metal complexes and to a lesser extent by electronic effects. Experimental data is well supported by Quantum mechanical calculations.