New synthetic routes to biscarbonylbipyridinerhenium(I) complexes cis,trans-[Re(X(2)bpy)(CO)(2)(PR3)(Y)](n+) (X(2)bpy=4,4 '-X-2-2,2 '-bipyridine) viaphotochemical ligand substitution reactions, and their photophysical and electrochemical properties
K. Koike et al., New synthetic routes to biscarbonylbipyridinerhenium(I) complexes cis,trans-[Re(X(2)bpy)(CO)(2)(PR3)(Y)](n+) (X(2)bpy=4,4 '-X-2-2,2 '-bipyridine) viaphotochemical ligand substitution reactions, and their photophysical and electrochemical properties, INORG CHEM, 39(13), 2000, pp. 2777-2783
Photochemical ligand substitution of fac-[Re(X(2)bpy)(CO)(3)(PR3)](+) (X(2)
bpy = 4,4'-X-2-2,2'-bipyridine; X = Me, H, CF3; R = OEt, Ph) with acetonitr
ile quantitatively gave a new class of biscarbonyl complexes, cis,trans[Re(
X(2)bpy)(CO)(2)(PR3)(MeCN)](+), coordinated with four different kinds of li
gands. Similarly, other biscarbonylrhenium complexes, cis, trans-[Re(X(2)bp
y)(CO)(2)(PR3)(Y)](n+) (n = 0, Y = Cl-; n = 1, Y = pyridine, PR'(3)), were
synthesized in good yields via photochemical ligand substitution reactions.
The structure of cis,trans-[Re(Me(2)bpy)(CO)(2){P(OEt)(3)}(PPh3)] (PF6) wa
s determined by X-ray analysis. Crystal data: C38H42N2O5F6P3Re, monoclinic
P2(1)/a, a = 11.592(1) Angstrom, b = 30.953(4) Angstrom, c = 11.799(2) Angs
trom, V = 4221.6(1) Angstrom(3), Z = 4, 7813 reflections, R = 0.066. The bi
scarbonyl complexes with two phosphorus ligands were strongly emissive from
their (MLCT)-M-3 state with lifetimes of 20-640 ns in fluid solutions at r
oom temperature. Only weak or no emission was observed in the cases Y = Cl-
, MeCN, and pyridine. Electrochemical reduction of the biscarbonyl complexe
s with Y = Cl- and pyridine in MeCN resulted in efficient ligand substituti
on to give the solvento complexes cis,trans-[Re(X(2)bpy)(CO)(2)(PR3)(MeCN)]
(+).