The syntheses, structures, and spectroscopic properties are According to the 1 H-and 13 C-NMR and resonance Raman spectra the imine groups of the iPr-DAB ligand are reported for trans,cis and cis,cis isomers of [Ru(I)(Me)(CO) 2 (α-diimine)] [α-diimine = N,NЈ-diisopropyl-inequivalent in the cis,cis isomer. The absorption spectra vary with the α-diimine, not so much with the isomeric 1,4-diazabutadiene (iPr-DAB), pyridine-2-carbaldehyde Nisopropylimine (iPr-PyCa), 4,4Ј-dimethyl-2,2Ј-bipyridine structure of the complex. Both isomers possess two visible absorption bands, which, according to the resonance Raman (dmb)] which differ in their photochemical behaviour. The structures of trans,cis-and cis,cis-[Ru(I)(Me)(CO) 2 (iPr-DAB)] spectra, belong to charge transfer transitions from mixed metal-halide orbitals to the α-diimine. The resonance Raman have been determined by a single-crystal X-ray diffraction study. The crystals of both isomers are monoclinic and belong spectra show that this charge transfer excitation is accompanied, for both isomers, with an angular distortion of to the same P2 1 /n space group with Z = 4. Refinement converged to R = 0.043 for the trans,cis isomer and to R = the methyl ligand. These spectral data show that the difference in photochemical behaviour of the two isomers is 0.065 for the cis,cis isomer. Both complexes have a distorted octahedral geometry, in the cis,cis isomer the methyl ligand not due to a change in the excited state character. is located in an equatorial, the iodide in an axial position.
Crystal Structure of cis,cis-[Ru(I)(Me)(CO) 2 (iPr-DAB)]