Photochemistry and Photophysics of Coordination Compounds

Photochemistry and Photophysics of Coordination Compounds: Copper 107
There are other examples of luminescent clusters, for instance trinuclear
copper(I) pyrazolates displaying emission bands over a wide spectral
range [156], or others with a core made of four Cu(I) and four sulfur
atoms [157, 158]. There are examples of Cu(I) luminescent clusters with
a higher nuclearity, some of them are heterometallic (6–8 metal centers) [159]
while others are homometallic but with a higher nuclearity (16–20 metal centers).
In the latter case, which bear alkynyl ligands [160], an emission band is
observed in the UV spectral region. Finally, the possible use of copper cluster
units to assemble polymeric compounds with a wide range of possible
structures, from one- to three-dimensional should be noted [161, 162].
5
Miscellanea of Cu(I) Luminescent Complexes
IntheprevioussectionswehavepresentedthethreemainclassesofCu(I)
compounds exhibiting interesting photophysical properties, namely Cu(I)bisphenanthrolines,
[Cu(NN)(PP)] + complexes and cuprous clusters. However,
especially in recent years, a growing number of Cu(I) luminescent complexes
with less conventional ligands have appeared in the literature and some
of them will be now briefly presented.
The homoleptic Cu(I) complexes of the benzo[h]quinoline ligands (BHQ)
depicted in Fig. 36 exhibit excellent luminescence properties in CH2Cl2
withquantumyieldsashighas0.10andτ = 5.3 µs (ligandC in Fig. 36),
Fig. 36 Benzo[h]quinoline ligands which, upon complexation with Cu(I), provide highly
luminescent complexes