posted on 2020-08-24, 20:14authored byMatthew
J. Stout, Brian W. Skelton, Alexandre N. Sobolev, Paolo Raiteri, Massimiliano Massi, Peter V. Simpson
Three
Re(I) tricarbonyl complexes,
with the general formulation
Re(N^L)(CO)3X (where N^L is a bidentate ligand containing
a pyridine functionalized at position 2 with a thione or a thiazol-2-ylidene
group and X is either chloro or bromo), were synthesized and their
reactivities explored in terms of solvent-dependent ligand substitution,
in both the ground and excited states. When they were dissolved in
acetonitrile, the complexes bound to the thione ligand underwent reversible
ligand exchange with the solvent, resulting in the formation of Re(NCMe)2(CO)3X; the starting complex could be re-formed
by precipitation following addition of diethyl ether. On the other
hand, the complexes appeared to be inert in dichloromethane or acetone.
Conversely, the complex bound to the thiazol-2-ylidene ligand did
not display any ligand exchange reaction in the dark but underwent
photoactivated ligand substitution on excitation to its lowest metal
to ligand charge transfer manifold. Photolysis of this complex in
acetonitrile generated multiple products, including Re(I) tricarbonyl
and dicarbonyl solvato complexes as well as free thiazol-2-ylidene
ligand.