50420-46-7Relevant academic research and scientific papers
Phosphine- and thiophosphorane-amine ligands: Lithiation and coordination to Rh(I)
Payet, Elina,Auffrant, Audrey,Le Goff, Xavier F.,Floch, Pascal Le
experimental part, p. 1499 - 1506 (2010/08/03)
A series of phosphine-amine and thiophosphorane-amine ligands (PR2(X)CH2NHR′, X = lone pair, S, R = Ph, Cy, R′ = tBu, Ph) differing by the nature of the phosphorus and nitrogen substituents were synthesized. Their lithiation, in order to generate the corresponding amido ligand mainly led to dissociation with formation of phosphide or thiophosphinite anion and imine. DFT calculations confirmed that this pathway is in most cases thermodynamically favoured. But for a phosphine-amido anion featuring alkyl substituents on the P atom and phenyl on the nitrogen, calculations showed that the dissociation is strongly disfavoured (ΔG = +24.3 kcal mol-1). Actually, {PCy2CH2NPhLi} was isolated in high yield and fully characterized. This phosphine-amido ligand and the corresponding amine derivative were then coordinated to Rh(I) metal centre.
Sterically crowded diphosphinomethane ligands: Molecular structures, UV-photoelectron spectroscopy and a convenient general synthesis of tBu2PCH2PtBu2 and related species
Eisentraeger, Frank,Goethlich, Alexander,Gruber, Irene,Heiss, Helmut,Kiener, Christoph A.,Krueger, Carl,Notheis, J. Ulrich,Rominger, Frank,Scherhag, Gunter,Schultz, Madeleine,Straub, Bernd F.,Volland, Martin A. O.,Hofmann, Peter
, p. 540 - 550 (2007/10/03)
A series of highly crowded symmetric and unsymmetric diphosphinomethanes R2PCH2PR′2, important ligands in transition metal chemistry and catalysis, namely tBu2PCH2ptBu2 (dtbpm, 11), Cy2PCH2PCy2 (dcpm, 2), tBu2PCH2PCy2 (ctbpm, 3), tBu2PCH2PiPr2 (iptbpm, 4) and tBu2PCH2PPh2 (ptbpm, 5), has been prepared in high yields, using a general and convenient route, which is described in detail for 1. Other than 4, which is a colourless liquid, these compounds are crystalline solids at room temperature. Their molecular structures have been determined by single crystal X-ray diffraction, along with that of the higher homologue of 1, tBu2CH2CH2tBu 2 (dtbpe, 6). The solid-state structures of the dioxide of 1, tBu2P(O)CH2P(O)tBu2 (7), and of two phosphonium cations derived from 1, protonated [tBu2P(H)CH2PtBu2] + (8+) and the chlorophosphonium ion [tBu2P(Cl)CH2PtBu2] + (9+), are also described and show a distinct structural influence of the tetracoordinate P centres. The gas phase UV-photoelectron spectra of the diphosphines 1-6 have been measured. Their first two ionisation potentials are found to be nearly degenerate and all are in the low energy range from 7.5 to 7.8 eV. Comparison with related mono- and bidentate phosphines demonstrates that 1-6 are excellent σ-donors towards metals, in accord with their known coordination chemistry. Molecular geometries and electronic structures of the diphosphine systems have been studied by quantum chemical calculations and are compared to experiment. Unlike standard semiempirical methods (AM1, PM3, MNDO), which give rather poor minimum structures and seem inadequate for such sterically crowded systems, ab initio calculations (RHF/6-31G**) predict molecular geometries with reasonable accuracy and reflect the observed trends in experimental ionisation potentials.
Regio- and Stereo-selectivity in the Hydrogenation of Aryl Phosphines by Niobium Aryloxide Compounds
Potyen, Mark C.,Rothwell, Ian P.
, p. 849 - 852 (2007/10/02)
The sequential hydrogenation of the three aryl rings in PPh3 by the catalyst system /3BunLi occurs with relative rates of 39:28:1; NMR analysis of the PhPCy2 obtained from and shows a predominantly all cis hydrogenation of both aryl rings has occurred.
DARSTELLUNG UND REAKTIONEN EINIGER LITHIUMPHOSPHINOFORMIATE R2PCOOLi UND RHPCOOLi - AB INITIO-RECHNUNGEN IM SYSTEM H2PCOOH-PH3/CO2
Diemert, K.,Hahn, T.,Kuchen, W.,Tommes, P.
, p. 65 - 76 (2007/10/02)
The preparation of lithiumphosphinoformates R2PCOOLi 1 (R = Ph, c-Hexyl, i-Pr, Et) and RHPCOOLi 2 (R = Ph, c-Hexyl) from R2PLi or RHPLi and CO2 is described.In the latter reaction RP(COOLi)2 3 and RPH2 are formed in addition to 2.In protic media 1-3 are rapidly decomposed with decarboxylation and formation of R2PH and RPH2, respectively.Reactions of 1 with MeI, (MeO)2SO2, Me3SiCl and CS2 are similar to those of Ph2PCOONa and no significant influence of R was detected.With (MeO)2SO2 mixtures of 2 and 3 gave esters RHPCOOMe and RP(COOMe)2 while with Me3SiClRHPCOOSiMe3 was obtained as the sole product.Ab initio MO calculations (GAUSSIAN 90 system of programs; HF/3-21G*, HF/6-31G** and MP2/6-31G** basis sets) showed the phosphinoformic acid to be less stable than its decomposition products, from which it is separated by a high barrier of isomerization.Therefore the acid should be stable in the rarefied gas phase.Key words: Li-Phosphinoformates; R2PCOOLi; RHPCOOLi; RP(COOLi)2; ab initio MO calculations; H2PCOOH-PH3/CO2.
Catalytic Hydrogenation of Aryl Phosphines by Niobium Aryloxide Compounds: High Yield and Efficient Synthesis of Cyclohexyl Phosphine Ligands
Yu, Joyce S.,Rothwell, Ian P.
, p. 632 - 633 (2007/10/02)
The tris(4-methylbenzyl) compound Nb(OC6H3Ph2-2,6)2(CH2H4-4Me)3 1 (OC6H3Ph2-2,6 = 2,6-diphenylphenoxide) acts as a catalyst precursor for the hydrogenation of a variety of aryl phosphine ligands.
