Base adducts of .beta.-ketoenolates. VII. Electron paramagnetic resonance studies of some fluxional 1,1,1,6,6,6-hexafluoro-2,4-pentanedionatocopper(II) complexes

Polymorphism in uranyl chelate complexes. Part 2. The crystal and molecular structure of the alpha form of bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)dioxo(trimethyl phosphate)uranium(VI)

“…This tilting could be caused by the inter- have been determined. [25][26][27][28][29][30][31][32][33][34][35] In all of these the diketone ring is planar with delocalisation, and the dihedral angles between the ring and the co-ordination planes lie between 0 and 17". The C-0 distances are about the same as in Hhfpd, and i.r.…”

Single-crystal electronic and electron spin resonance spectra of three tris-chelate copper(II) complexes

“…This situation is unlikely to give rise to the observed polarization of the electronic spectra and the clear rhombic crystal g factors. A more likely fluxional behavior is the pseudo Jahn-Teller type distortion postulated for Cu-(hfacac)2(py)2 24 where clear rhombic g factors were observed (which varied slightly with temperature), and yet the electronic spectra showed no polarization or even change of intensity with orientation. As the polarized single-crystal spectra of Cu(bipy)3(C104)2 and Cu(phen)3(C104)2 show clear polarization (Figure 4B and C), fluxional behavior is unlikely to be present in these complexes, but as the spectra of {C14H19N2}{Cu(hfacac)3} only show a change of intensity with orientation, fluxional behavior is possible in tills complex.…”