Reinvestigation of the nickel phosphine catalysed electrochemical synthesis of poly(2,5-pyridine). X-Ray crystal structures of [Ni2Br2(µ-5-BrC5H3N-C2,N)2(PPh3)2] and [PtBr(5-BrC5H3N-C2)(PPh3)2]

Abstract

Poly(2,5-pyridine) films have been deposited on glassy carbon, platinum and gold electrodes by the electroreduction of a novel binuclear nickel complex, trans(P,N)-bis[bromo(µ-5-bromopyridyl-C²,N)(triphenylphosphine) nickel(II)]. The synthesis, characterisation and electropolymerisation of this complex are described. The results from analytical and electrochemical investigations of poly(2,5-pyridine) are presented. The resultant poly(2,5-pyridine)-modified electrodes display electroactivity in their reduced state and co-ordinate nickel ions. The synthesis and electrochemistry of the analogous platinum and palladium complexes are also discussed. The X-ray crystal structures of the Ni and Pt complexes have been determined. The binuclear Ni complex contains Ni—(C₅H₄N)—Ni bridges, and the Ni atoms are also co-ordinated by one Br and one PPh₃. The platinum complex is mononuclear with the Pt bound to the C₂ of the pyridyl ring, to Br and to two trans PPh₃ groups.