RHODIUM COMPLEXES CONTAINING THE TRI-3-BUTENYLARSINE LIGAND

Article abstract of DOI:10.1016/S0022-328X(00)92893-6

The potential tetradentate ligand tri-3-butenylarsine (tba) reacts with 2 (cod=cycloocta-1,5-diene) and 2 to give either 2 or depending on the reaction conditions.The complex 2 undergoes bridge-cleavage reactions with phosphines and carbon monoxide to give the compounds ; the compound where L=PPh3 has also been obtained from reaction between tba and .The square-planar complex forms the corresponding bromo- and iodo-derivatives by metathetical halogen exchange; reacts with NaBPh4 to give 2-C6H5BPh3)>; and with CO affords .Pyridine displaces the CO ligand in this last compound to give , and both and the triphenylphosphine analogue ionise in polar solvents, and yield BPh4 (L=CO or PPh3) with NaBPh4.Reaction between tba and 2 is complex, giving <(tba)Rh(μ-Cl)2Rh(CO)2> as the major product with a 1:1 molar ratio of reactants, but cis- and trans-<(tba)(CO)Rh(μ-Cl)2Rh(CO)(tba)> with a 2:1 molar ratio, and with a 4:1 excess of tba at room temperature.The structures of these various compounds are discussed in the light of IR and variable temperature 1H NMR spectroscopic evidence.