REINVESTIGATION OF THE NICKEL PHOSPHINE CATALYZED ELECTROCHEMICAL SYNTHESIS OF POLY(2,5-PYRIDINE) - X-RAY CRYSTAL-STRUCTURES OF [NI2BR2(MU-5-BRC5H3N-C2,N)2(PPH3)2] AND [PTBR(5-BRC5H3N-C2)(PPH3)2]

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(mu-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.