inorganic chemistry

state from the^3 MLCT state (Scheme 2) and by using Eqs. (5)–(10)
as shown in Figs. 11 and 12.

kr¼

Fr

te

¼k^0 rexp

DE

RT



ð 5 Þ

ke¼

Fe

te

¼k^0 eexp

DE

RT



ð 6 Þ

k^0 d¼k^0

0

dexp

DE

RT



ð 7 Þ

Fe¼

ke

ðÞkeþkdþk^0 dþkr

ð 8 Þ

Fr¼

kr

ðÞkeþkdþk^0 dþkr

ð 9 Þ

te¼

1

ðÞkeþkdþk^0 dþkr

ð 10 Þ

The energy differences between the lowest excited^3 MLCT states
and the transition states of the photochemical ligand substitu-
tion reactions could be estimated from analysis of the tempera-
ture effects (Table IV). The evaluatedDG6¼values were found to
vary with the substituents on the bpy ligand (3650–4820 cm
^1 ).

TABLE III

PHOTOPHYSICALPROPERTIES OF[Re(X 2 bpy)(CO) 3 (PR 3 )]þ( 3 )INCH 3 CNAT298 K.

[Re(X 2 bpy)

(CO) 3 (PR 3 )]þ

le(nm) E 00 (^3 MLCT)a

(cm
^1 )

te(ns) Fe Fr

X PR 3

3a H P(OEt) 3 542 19,470 55 1034 0.155 0.089
3b CH 3 P(OEt) 3 533 19,637 50 936 0.175 0.16
3c CF 3 P(OEt) 3 623 17,272 49 162 0.031 0.0003
3d H P(n-Bu) 3 561 18,672 50 621 0.091 0.095
3e H PEt 3 561 18,649 51 654 0.153 0.15
3f H PPh 3 540 19,000 31 416 0.097 0.55
3g H P(OMe)
Ph 2

542 19,553 46 644 0.127 0.25

3h H P(Oi-Pr) 3 543 19,239 52 952 0.247 0.099
3i H P(OMe) 3 543 19,678 43 1076 0.216 0.118

a 0 – 0 band energy gap between the (^3) MLCT and the ground states.
RHENIUM(I) DIIMINE COMPLEXES 155