inorganic chemistry

stabilize Cu(I) but provides also an IL state for light absorption. For

our purpose, the complex (Pf 3 ) 2 CuI(m-CO 32 
)CuI(Pf 3 ) 2 should be a

suitable candidate. It was synthesized and characterized already in

1995 ( 36 ). For further stabilization we replaced Pf 3 by the

bidentate ligand prophos.

ComplexIis colorless, well soluble in organic solvents and does

not decompose in humid air. The absorption spectrum of I

(lmax¼279 nm; e¼15,400 M
^1 cm
^1 and lmax¼268 nm;

e¼16,800 M
^1 cm
^1 )inCH 3 CN (Fig. 1) remains unchanged for

days. However,Iis light sensitive. The irradiation is accompanied

by spectral variations including an isosbestic point at 231 nm

(Fig. 1). During the photolysis a continuous decrease of the

absorption atl>231 nm takes place. The photoproduct shows a

characteristic spectrum (Fig. 1) with a maximum at 263 nm and

further features atlmax¼256, 271, 284, and 296 nm. ComplexI

displays a weak luminescence atlmax¼440 nm (Fig. 2), which dis-

appears during the photolysis and is replaced by a much more

intense luminescence atlmax¼304 nm (Fig. 2). Further, maxima

appear at 282 (sh), 290, and 318 nm (sh).

The absorption and emission spectrum of the photolyzed solu-

tion can be unambiguously attributed to 1,3-bis(diph-

enylphosphino)propane monoxide (prophos oxide,II) as shown

by comparison with the spectra of an authentic sample ofII.

The phosphine oxide II is formed with a quantum yield of

0.8

0.4

0.0

210 260 310 360

l (nm)

A

b

a

FIG. 2. Spectral changes during the photolysis of 2.68 10
^5 M (pro-
phos)CuI(CO 3 )CuI(prophos) in acetonitrile at room temperature under
argon at 0 (a), 15 and 40 min (b) irradiation times withlirr¼313 nm
(Osram HBO 200 W/2 lamp), 1-cm cell.

PHOTOCHEMICAL ACTIVATION AND SPLITTING OF H 2 O 355