2,2'/6',2''-TERPYRIDINE (TERPY) ACTING AS A FLUXIONAL BIDENTATE LIGAND .3. RUTHENIUM CARBONYL HALIDE-COMPLEXES, [RUX(2)(CO)(2)(TERPY)] (X=CL, BR OR I) AND METAL TETRACARBONYL COMPLEXES [M(CO)(4)(TERPY)] (M=CR, MO OR W) - NUCLEAR-MAGNETIC-RESONANCE STUDIES OF THEIR SOLUTION DYNAMICS AND SYNTHESIS OF TRANS-[RUX(2)(CO)(TERPY)] (X=CL, BR OR L)

Under mild conditions 2.2':6',2''-terpyridine reacted with [(RuX(2)(CO)(2))(n)] (X = Cl, Br or I) and with [M(CO)(4)(nbd)] [M = Cr, Mo or W; nbd = norbornadiene (bicyclo[2.2.1]hepta-2,5-diene)] to form the octahedral complexes trans, cis-[RuX(2)(CO)(2)(terpy)] and [M(CO)(4)(terpy)l respectively, in which the terpyridine acts as a bidentate chelate ligand. In solution these complexes are fluxional with the terpyridine oscillating between equivalent bidentate modes. Heating trans,cis-[RuX(2)(CO)(2)(terpy)] (X = Cl, Br or I) in a high boiling solvent formed trans-[RuX(2)(CO)(terpy)] whereas cis-[RuX(2)(CO) (terpy)l was formed by heating the solid dicarbonyl complex.