Spectroelectrochemical Studies of Copper(I) Complexes with Binaphthyridine and Biquinoline Ligands. Crystal Structure Determination of Bis(6,7-dihydrodipyrido[2,3-<i>b</i>:3‘,2‘-<i>j</i>][1,10]phenanthroline)copper(I) Tetrafluoroborate

The electrochemical and spectral properties of some copper(I) polypyridyl complexes based on 6,7-dihydrodibenzo[b,j][1,10]phenanthroline, dmbiq, and 6,7-dihydrodipyrido[2,3-b:3‘,2‘-j][1,10]phenanthroline, dmbinap, are reported. These complexes are [Cu(dmbiq)2]+, 1; [Cu(dmbiq)(PPh3)2]+, 2; [Cu(dmbinap)2]+, 3; and [Cu(dmbinap)(PPh3)2]+, 4. 3 and 4 may be reduced to form ligand-based radical anion species. The resonance Raman spectra of 3•- and 4•- are almost identical and correspond closely to the spectrum of dmbinap•- and the reported spectra of complexes containing 2,2‘-biquinoline radical anion moieties. Reduction processes for 1 and 2 are irreversible. For 1 the electronic spectral changes arising from reduction suggest demetallation of the complex. The structure of [Cu(C18H12N4)2][BF4]·CH2Cl2 (3[BF4]·CH2Cl2) was determined by single-crystal X-ray diffraction. It crystallized in the monoclinic space group P21/c with cell dimensions a = 14.059(7) Å, b = 15.058(6) Å, c = 16.834(9) Å, β = 111.56(5) °, Z = 4, ρcalcd = 1.611 g/cm3, and R(Fo) = 0.0497.