inorganic chemistry

by the edge Re(I) tricarbonyl units is rapidly transferred to the
interior units( 49 ). The photophysical properties of linear-shaped
multinuclear complexes bridged by 1,2-bis(diphenylphosphino)
ethane (dppe) are summarized in Table VI.

F. PHOTOCHEMICALREACTIONS OFfac-Re(bpy)(CO) 3 ClFROM
HIGHEREXCITEDSTATES

As described above, most rhenium(I) diimine tricarbonyl
complexes for which the lowest excited state is the^3 MLCT state
are stable against irradiation with light of wavelength longer
than 340 nm. The exception is complexes with phosphorous lig-
ands (SectionIII.D). Actually, this kind of photochemical ligand
substitution reaction of fac-Re(diimine)(CO) 3 Cl and fac-[Re
(diimine)(CO) 3 (X-py)]þ(X-py¼pyridine derivative) does not pro-
ceed by irradiation usingl>330 nm light. However, it has been
recently reported that photochemical ligand substitution and
photochemical isomerization of 1a occur from higher excited
states.
Although1awas photostable under 366-nm irradiation, irradi-
ation with higher-energy light than 340 nm does cause

N

N

OC Re

OC

CO

PPR

N

N

Re

OC

CO

(n=2–20)

P

P

P =R P PP P

xP

PR P

N

N

Re

OC

CO

CO

n+

n-2

x=0– 3

FIG. 15. Linear-shaped Re(I) oligomers and polymers constructed
with bidentate phosphine ligands.

RHENIUM(I) DIIMINE COMPLEXES 163