ISSN:
1434-1948
Keywords:
Ruthenium
;
α-Diimine ligand
;
Carbonylmetal compounds
;
Isomers
;
X-ray structure
;
Resonance Raman spectra
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The syntheses, structures, and spectroscopic properties are reported for trans,cis and cis,cisisomers of [Ru(I)(Me)(CO)2(α-diimine)] [α-diimine = N,N′-diisopropyl-1,4-diazabutadiene (iPr-DAB), pyridine-2-carbaldehyde N-isopropylimine (iPr-PyCa), 4,4′-dimethyl-2,2′-bipyridine (dmb)] which differ in their photochemical behaviour. The structures of trans,cis- and cis,cis-[Ru(I)(Me)(CO)2(iPr-DAB)] have been determined by a single-crystal X-ray diffraction study. The crystals of both isomers are monoclinic and belong to the same P21/n space group with Z = 4. Refinement converged to R = 0.043 for the trans,cis isomer and to R = 0.065 for the cis,cisisomer. Both complexes have a distorted octahedral geometry, in the cis,cisisomer the methyl ligand is located in an equatorial, the iodide in an axial position. According to the 1H- and 13C-NMR and resonance Raman spectra the imine groups of the iPr-DAB ligand are inequivalent in the cis,cis isomer. The absorption spectra vary with the α-diimine, not so much with the isomeric structure of the complex. Both isomers possess two visible absorption bands, which, according to the resonance Raman spectra, belong to charge transfer transitions from mixed metal-halide orbitals to the α-diimine. The resonance Raman spectra show that this charge transfer excitation is accompanied, for both isomers, with an angular distortion of the methyl ligand. These spectral data show that the difference in photochemical behaviour of the two isomers is not due to a change in the excited state character.
Type of Medium:
Electronic Resource
