57894-45-8Relevant academic research and scientific papers
SYNTHESIS AND STRUCTURE OF Ru(CO)4. THE CONFORMATION OF THE TRIMETHYL PHOSPHITE LIGAND IN COMPLEXES.
Cobbledick, Roger E.,Einstein, Frederick W. B.,Pomeroy, Roland K.,Spetch, Edward R.
, p. 77 - 88 (1980)
Two methods of preparation of Ru(CO)4 from Ru3(CO)12 and P(OCH3)3 are described.The crystal structure of the compound has been determined from three-dimensional X-ray data collected by counter methods.The space group is P21/c with cell dimensions a 13.225(3), b 7.704(3), c 13.278(4) Angstroem and β 109.82(2)o.Intensity data for 1879 observed reflections were refined by conventional methods to R=0.044.The structure shows that the phosphite ligand does not have three fold symmetry.From a comparison of the infrared spectrum in the carbonyl region of Ru(CO)4 with that of the corresponding P(OCH2)3CC2H5 derivative it is concluded that the asymmetry of the ligand is maintained on the infrared time scale.The 13C and 1H NMR spectra however indicate the methyl groups are all equivalent on the NMR time scale, even at -120 deg C.The NMR study also indicated there is rapid exchange of the axial and equatorial carbonyl groups in solution.
Carbonylation of the Ru-Me bond of Ru(Me)(I)(CO)2(iPr-N=CHCH=N-iPr) catalyzed by Ru(CO)4(PR3), ZnCl2, and H+
Kraakman, Marco J. A.,De Klerk-Engels, Barbara,De Lange, Paul P. M.,Vrieze, Kees,Smeets, Wilberth J. J.,Spek, Anthony L.
, p. 3774 - 3784 (2008/10/08)
Reaction of the dimetallic compound Ru2(Me)(I)(CO)4(PR3)(iPr-DAB) (iPr-DAB = iPr-N=C(H)C-(H)=N-iPr; PR3 = P(nBu)3 (2a), PMe2Ph (2b), PMePh2 (2c), PPh3 (2d), P(OMe)3 (2e), P(OPh)3 (2f)) with carbon monoxide afforded a mixture of the monomeric complexes Ru(R)(I)(CO)2(iPr-DAB) (R = Me (3); R = C(O)Me (4)) and Ru(CO)4(PR3) (5a-f). It was found that with increasing basicity of the phosphine there is a stronger tendency to form the acetyl product 4, although 3 is formed initially for all phosphines used. Mechanistic studies showed that the conversion of 3 to 4 is catalyzed by Ru(CO)4(PR3), provided PR3 is sufficiently basic. The use of 13CO-enriched Ru(CO)4(PR3) led to the incorporation of 13CO into both the acetyl CO group and the terminal CO groups of 4, indicating the presence of a dimetallic intermediate, by which intermetallic CO exchange becomes possible. Further evidence for this was obtained from the observation that the conversion of 3 to 4 can also be effected in the absence of free CO, by reaction of 3 with Ru(CO)4(PMe2Ph) (5b) and L′ (L′ = PPh3, P(OPh)3). In addition to 4 the complex Ru(CO)3(PMe2Ph)(L′) is also formed under these conditions. Interestingly, reaction of 3 with 5b in the absence of both CO and L′ also gave carbonylation of the Ru-Me bond, which, however, was accompanied by transfer of a H-atom from an iPr-CH group to an imine C-atom, with formation of Ru(C(O)Me)(I)(CO)2(iPr-N= CH-CH2-N=C(Me)2) (7). Reaction of 3 with AgOTF yielded [Ru(Me)(CO)2(iPr-DAB)][OTF] (8), which in the presence of CO is rapidly converted to [Ru(C(O)Me)(CO)2(iPr-DAB)][OTF] (9), whereas 8 with tBu isocyanide and PMe2Ph gave [Ru(Me)(CO)2(L)(iPr-DAB)][OTF] (L = tBu-NC (10), PMe2Ph (11)). Attempts to carbonylate the Ru-Me bond in complexes 10 and 11 were not successful. Finally it was shown that the carbonylation of the Ru-Me bond of 3 could also be promoted by H+ and ZnCl2. Single-crystal X-ray structure determinations of complexes 4 and 8 have been carried out, and their molecular structures are discussed. Salient features are that 4 has a configuration similar to that of 3; i.e., the acetyl group is trans to I. The trifluorosulfonate anion in 8 is found to be η1-coordinated to the ruthenium center and trans to the methyl group. Crystals of 4 (C12H19N2O3RuI) are monoclinic, space group P21/n, with a = 8.556 (1) A?, b = 18.510 (2) A?, c = 10.500 (1) A?, β = 94.90 (1)°, V = 1656.7 (3) A?3, Z = 4, and final R = 0.0435 for 2565 reflections with I > 2.5σ(I) and 188 parameters. Crystals of 8 (C12H19F3N2O5RuS) are monoclinic, space group P21/c, with a = 8.288 (1) A?, b = 25.839 (2) A?, c = 17.994 (1) A?, β = 100.47 (1)°, V = 3789.1 (6) A?3, Z = 8, and final R = 0.0476 for 3917 reflections with I > 2.5σ(I) and 500 parameters.
