41509-48-2Relevant academic research and scientific papers
Rh(I) carbonyl carboxylato complexes: Spectral and structural characteristics. Some reactions of coordinated formate group
Varshavskii,Cherkasova,Podkorytov,Korlyukov,Khrustalev,Nikol'skii
, p. 121 - 131 (2008/10/09)
Complexes [Rh(μ-RCOO)(CO2)]2, where R = H, CH 3, CF3 (I, II, III, respectively) are synthesized by reacting anhydrous carboxylic acids with Rh(Acac)(CO2) crystals. In compounds I, II, III, and trans-Rh(RCOO)(PPh3)2(CO), where R = H, CH3, CF3 (IV, V, VI, respectively), ν(CO) and 1J(CRh) increase and δ13C decreases with the increasing electronegativity of R (CH3 3). In the case complexes IV, V, and VI, the values of δ31P and 1J(PRh) decrease in the same order. Complexes I and V are studied by X-ray diffraction analysis. Intramolecular (2.946 A) and intermolecular (3.127 A) Rh-Rh distances in a columnar structure I are close, i.e., the structure contains infinite chains of metal atoms. Interaction of IV with chlorinated solvents results in trans-RhCl(PPh3)2(CO). When heated with an excess of PPh3 in propanol-2, compound IV transforms to HRh(PPh3)3(CO). The latter reaction was suggested as a basis of a new method that can be used to obtain HRh(PPh 3)3(CO).
X-RAY PHOTOELECTRON SPECTRA OF Rh(III) TRIFLUOROACETATE
Shul'ga, Yu. M.,Gol'dshleger, N. F.,Rubtsov, V. I.,Sokol, V. I.
, p. 1193 - 1195 (2007/10/02)
A study was made of the x-ray photoelectron spectra of Rh(I) and Rh(III) trifluoroacetates complexes.It was shown by using the C1s bond energies of the carboxylate carbon atom as a basis that bridging and monodentate coordination of the trifluoroacetate group could be distinguished with high resolution. Keywords: photoelectron spectra, Rh(III) trifluoroacetate.
Migration of a hydride ligand to a difluorocarbene ligand bound to rhodium. The synthesis and crystal structure of RhCl2(CF2H)(PPh3)2
Burrell, A. K.,Clark, G. R.,Jeffrey, J. G.,Rickard, C. E. F.,Roper, W. R.
, p. 391 - 408 (2007/10/02)
Rh(CF3)(CO)(PPh3)2 has been made by treating RhH(CO)(PPh3)3 with Hg(CF3)2, and found to display reactivity consistent with a 16 e-, d8 complex, in that it undergoes addition of a number of small molecules, including O2, X2 (X = Cl, Br, I) and MeI.Treatment of Rh(CF3)(CO)(PPh3)2 with aqueous acids results in hydrolysis of the trifluoromethyl group to a carbonyl ligand.Confirmation that this reaction proceeds via a difluorocarbene intermediate came from the reaction with dry HCl, which gave RhCl2(CF2H)(CO)(PPh3)2.A study of this reaction, by multinuclear NMR spectroscopy and 2H-labelling experiments led to the proposal of a mechanism for the formation of RhCl2(CF2H)(CO)(PPh3)2 that involves hydride migration to a cationic difluorocarbene ligand bound to rhodium.Another difluoromethyl complex RhCl2(CF2H)(PPh3)2 is formed when RhHCl2(PPh3)3 is treated with Hg(CF3)2.The crystal structure of this complex has been determined, and displays square pyramidal geometry with the CF2H ligand occupying the apical position.
Relative affinities of carbonylbis(triphenylphosphine)rhodium(I) and related cations for anionic ligands in CH2Cl2
Araghizadeh, Farshid,Branan, Daniel M.,Hoffman, Norris W.,Jones, John H.,McElroy, E. Andrew,Miller, Nathan C.,Ramage, David L.,Salazar, Anna Battaglia,Young, Sidney H.
, p. 3752 - 3755 (2008/10/08)
Infrared spectroscopy has been used to determine the relative anion affinities in CH2Cl2 of Rh(PPh3)2(CO)+ and Rh(AsPh3)2(CO)+ via measurement of equilibrium constants for the metatheses RhL2(CO)Y + PPN+Z- = RhL2(CO)Z + PPN+Y-. Observed for L = PPh3 was the anion affinity trend NCO- ? O2CMe- ～ O2CPh- ? F- ～ NCS- > Cl- > Br- > I- ? ONO2- ～ O2CCF3- ? OTf- ～ OClO3-. A smaller series for L = AsPh3 displayed a similar trend, but with positions of NCS- and Cl- reversed. For most anion pairs studied, the equilibrium lies so far to the left or right that only limits could be calculated, given the inherent experimental limitations. For L = PPh3, the equilibrium constant for replacement of the least preferred anion by the most can be inferred as >1019. Rh(PCy3)2(CO)Cl and Rh(PCy3)2(CO)Z (Z = NCS, NCSe, O2CMe; but not F, O2CPh, and NCO) interact strongly in solution and thus limit study of that series.
