Copper-pyridine charge-transfer

Figure 6.1-14 To illustrate the molecular (o) enhancement of SERS due to resonance Raman scattering for excitation into a charge transfer band of the adsorbate-metal-surface-complex the filled 7t and empty TC orbital levels of pyridine and the metallic density of states of copper are shown on the left- and right-hand side, respectively for details see text (Creighton, 1986).

A somewhat different situation is presented by the pressure effects seen in the emission spectra of the rhenium(I) complex ReBr(CO)3(phen) and the copper(I) cluster Cu4I4py4 (where py = pyridine) and related species. The former displays strong MLCT emission in ambient temperature fluid benzene [35] solutions while the latter displays a strong emission from an cluster centered (CC) excited state assigned as having mixed d-to-s metal-centered and iodide-to-copper charge-transfer character [36]. In each case, the emission is markedly dependent on the rigidity of the medium, and... 

Bipyridine (bpy) diboronic acid 239 developed by Nakashima and its iron (II) (as FeC12) complex produce CD-active saccharide complexes. The CD activity of 239 was derived from the asymmetric immobilization of the two-pyridine units on saccharide binding. The copper(II) complex gave a CD band in the region of the metal to ligand charge transfer band. A or A complexes were found depending on the complexed saccharide. For example, the o-maltose complex adopted A chirality whereas the o-cellobiose complex adopted A chirality. 

Photoexcitation (X = 313 nm) of the charge-transfer adducts of N with CuBr(Py)(PPh3) or Cu[HB(Pz)3] in hexane (Py = pyridine, Pz = 1-pyrazolyl) gives rise to Q with = 0.37-0.65. The photorearrangement of the complexes of N with halo(ferrocenyl-diphenylphosphine)copper(I) tetramers... 

---