72868-86-1Relevant academic research and scientific papers
Substitution of chloride in [PtCl2(dppe)] by the chiral anionic ligand [Mo(CO)5(PPhH)]-: Synthesis and X-ray structure of [Pt(μ-PPhH)2{Mo(CO)5}2(dppe)] and a 31P{1H} NMR analysis of its isomeric products and fluxionality
Deeming, Antony J.,Doherty, Simon
, p. 1175 - 1190 (1996)
Reaction of the chiral anionic ligand [Mo(CO)5(PPhH)]- with [PtCl2(L-L)] affords the neutral trimetallic monophosphido bridged complexes [Pt(μ-PPhH)2{Mo-(CO)5}2(L-L)] (L-L = dppe, Ph2PCH2CH2PPh2, 2; dpae, Ph2AsCH2CH2AsPh2, 3; dppe′, cis-Ph2PCH=CHPPh2, 4). Compounds 2-4 are the first examples of heterometallic complexes that contain two chiral primary phosphido bridges existing as pairs of diastereoisomers. [Pt(μ-PPhH)2{Mo(CO)5}2(dppe)] (2) has been characterized spectroscopically and by a single-crystal X-ray analysis. The molecular structure of 2 can be considered either as Mo2Pt phosphido-bridged trimer or a square-planar PtII complex bonded to one chelating dppe and two anionic phosphine ligands. The latter PtP4 description successfully accounts for the line broadening observed in the 31P{1H} NMR spectra of 2-4, which can be understood in terms of the existence of several interconverting rotameric forms arising from restricted rotation about the Pt-phosphido bond. The Pt - P - Mo angles of 122.1(1) and 123.5(1)° are some of the largest ever to be reported for phosphido-bridged heterometallics, reflecting the long Pt - Mo separations [4.349(2) and 4.320(2) A] and the electronic and structural flexibility of the phosphido bridge. The PtMo compound [Pt(μ-PPhH)2{Mo-(CO)4}(dppe)] (5), comprised of one neutral and one dianionic chelate ligand, was prepared from [Li]2[Mo(CO)5(PPhH)2] and [PtCl2(dppe)] and was shown to contain a conformationally rigid PtP4 structure with characteristically sharp 31P resonances. The 31P{1H} NMR spectrum of 5 is rich with information analysing as two overlapping AA′XX′ spin systems together with their AA′XX′M (M = 195Pt) counterparts. The values of 2J(P - P) and 1J(195Pt - P) are significantly lower for PPhH{Mo(CO)5}- than dppe, a difference that cannot be accounted for solely on the basis of bond length variations. Meso-[Pt(μ-PPhH)2{Mo(CO)5}2(dppe)] (2) is thermodynamically unstable, undergoing a rapid intramolecular elimination of [Mo(CO)6] to generate [Pt(μ-PPhH)2{Mo(CO)4}(dppe)] (5), while its racemic diastereoisomer, that which was observed in the crystal, decomposes to unidentified phosphorus-containing products.
The "phospha-Wittig" reaction: A new method for building phosphorus-carbon double and single bonds from carbonyl compounds
Marinetti, Angela,Bauer, Siegfried,Ricard, Louis,Mathey, Fran?ois
, p. 793 - 798 (2008/10/08)
The so-called "phospha-Wittig" reagents [(EtO)2P(O)PHR]M(CO)5 (M = Mo, W) are obtained via the reaction of primary phosphine complexes (RPH2)M(CO)5 with lithium diisopropylamide and diethyl chlorophosphate. The corresponding anions [(EtO)2P(O) - P-R]M(CO)5 react with carbonyl compounds under mild conditions to give the phosphaalkene complexes [R1R2C=PR]M(CO)5. A study of this reaction with R = Ph, R1 = i-Pr, and R2 = H has shown that the kinetic product is the (Z)-phosphaalkene complex, whereas the thermodynamic product is the E isomer. The stereochemistry of these complexes was established by X-ray crystal structure analysis. With α-diketones, only one carbonyl bond is converted into a P=C double bond, probably for steric reasons. Most of the phosphaalkene complexes thus obtained easily react with methanol or 2,3-dimethylbutadiene. The phosphane-Mo(CO)5 complexes synthesized via such a scheme are easily transformed into the corresponding P-sulfides by simple heating with sulfur in toluene. Thus, the "phospha-Wittig" reaction can also be viewed as a new tool for building organophosphorus species with P - C single bonds.
Reactions of Coordinated Ligands, VII. Syntheses and Reactions of Transition Metal Carbonyl Complexes of PH-Functional Di-, Tri-, and Tetraphosphanes
Baacke, Michael,Morton, Stephen,Johannsen, Gerd,Weferling, Norbert,Stelzer, Othmar
, p. 1328 - 1342 (2007/10/02)
The synthesis of complexes of PH-functional diphosphanes (CO)mM(PhPH - PR2)n (M = Mo, m = 4, 5, n = 2, 1, R = Ph, tBu; M = Fe, m = 4, n = 1, R = Ph) (7 - 10) and of 1,2,3-triphenyltriphosphane (CO)mM - PPhH - PPh - PPhH - M(CO)m (M = Mo, Fe, m = 5, 4) (13, 14) is reported.The availability of PH-functional groups as well as uncoordinated P-atoms in these compounds permits the formation of new P - P-bonds and of heterometallic complexes such as (CO)5Mo(PhPH - PPh2)Ni(CO)3 (16) or (CO)5Mo - PPhH - PPhPPhH - Mo(CO)5 (17).The 1H- and 31P NMR spectra of the complexes 4 - 10 and 13 - 20 are discussed.For complexes of 1,1,2,3,3-pentaphenyltriphosphane, (Ph2P)2PPH - M(CO)m (M = Mo, Fe, m = 5, 4) the migration of the (CO)mM group from the medial to the terminal position of the P3-skeleton could be observed by means of 31P NMR spectroscopy.
