287402-93-1Relevant academic research and scientific papers
First examples of [Rh(Bident)(CO)(L)] complexes where L is N-donor ligand: Molecular structure of [Rh(8-Oxiquinolinato)(CO)(NH3)]
Varshavsky,Galding,Cherkasova,Smirnov,Khrustalev
, p. 5788 - 5794 (2007)
Selective oxidation of one (trans to N) carbonyl group in [Rh(8-Oxiquinolinato)(CO)2] with stoichiometric amount of Me3NO in MeCN produces a solution containing [Rh(Oxq)(CO)(Me3N)] and [Rh(Oxq)(CO)(MeCN)]. The ammonia complex, [Rh(Oxq)(CO)(NH3)], has been prepared by action of NH3 gas on this solution and characterized by IR, 1H and 13C NMR, and X-ray data. Spectral parameters, ν(CO), δ 13C, and 1J(CRh), were measured in situ for a series of complexes [Rh(Oxq)(CO)(L)] (L = NAlk3, Py, PBu3, PPh3, P(OPh)3, C8H14) formed upon action of L on [Rh(Oxq)(CO)(NH3)] in THF. A new ν(CO) and δ 13C based scale of σ-donor/π-acceptor properties of ligands L is proposed including NH3 and CO as the natural endpoints.
Rh(acac)(CO)(PR3) and Rh(oxinate)(CO)(PR3) complexes - Substitution chemistry and structural aspects
Simanko, Walter,Mereiter, Kurt,Schmid, Roland,Kirchner, Karl,Trzeciak, Anna M.,Ziolkowski, Jozef J.
, p. 59 - 64 (2007/10/03)
The substitution of CO in Rh(acac)(CO)2 by the phosphorus ligands P(OPh)3, P(NC4H4)3, and PPh2(NC4H4) has been studied kinetically by stopped-flow spectrophotometry as a function of temperature. With P(OPh)3 and P(NC4H4)3, both CO ligands are replaced in a stepwise fashion via the intermediate Rh(acac)(CO)(PR3). However, the disubstituted complexes Rh(acac)(PR3)2 are thermodynamically unstable. Judged from the activation parameters, the individual steps are associative processes. In the case of PPh2(NC4H4) only the monosubstituted complex is formed. The differences in the substitution rates as well as the stability of the various products are largely dominated by electronic (e.g. basicity) effects. X-ray structures of some of the mono-substituted complexes are given. In addition, also the reaction of Rh(oxinate)(CO)2 with P(OPh)3 has been studied kinetically showing that oxinate has a labilizing effect relative to acetylacetonate
CYCLOMETALLATION REACTIONS IN COMPLEXES OF THE TYPE Rh(oq)(CO). THE MOLECULAR STRUCTURE OF (oq = 8-hydroxyquinolinate)
Barcelo, F. L.,Besteiro, J. C.,Lahuerta, P.,Foces-Foces, C.,Cano, F. H.,Martinez-Ripoll, M.
, p. 343 - 352 (2007/10/02)
Cyclometallation occurs when a solution of the complex Rh(oq)(CO)(PCBr), (PCBr = 2-bromo-3,4,5,6-tetraffluorophenyldiphenylphosphine; oq = 8-hydroxyquinolinate) in toluene is refluxed, giving (PC = P(C6F4)(C6H5)2) and a dimeric compound, not yet completely characterized, formulated as Rh2Br(oq)(PCBr)2. was characterized by elemental analysis, by conductance measurements, and by 19F, 31P NMR and infrared spectroscopy.Its molecular structure was determined by single-crystal X-ray methods and refined by standard procedures to final agreement factors R and Rw of 0.067 and 0.060 for 5346 observed data.Lattice constants are 15.8494(6), 14.7188(5), 14.6675(5) Angstroem and β 96.933(3) deg, with monoclinic symmetry.The complex has a distorted octahedral geometry with a four atom metallocycle-ring (Rh-P-C-C) showing distorted angles of 69.8(2) and 84.8(2) deg at Rh and P atoms, respectively.The analogous compound , (5-moq = 5-methyl-8-hydroxyquinolinate), can be obtained by heating Rh(5-moq)(CO)(PCBr).
