74679-92-8Relevant academic research and scientific papers
Oxo-rhenium(V) complexes with analogs of bis(diphenylphosphino)ethane
Sigouin, Olivier,Beauchamp, André L.
, p. 4489 - 4496 (2005)
Compounds of the types ReOCl3(L-L) and ReOCl2(OEt)(L- L) with bis(diphenylphosphino)ethene (dppen) and bis(diphenylphosphino)ferrocene (dppf) were prepared by reacting the diphosphine with ReOCl 3(OPPh3)(Me2S). The ReOCl3(L-L) compound with bis(diphenylarsino)ethane (dpae) was prepared similarly. Crystallographic work on ReOCl3(dppen) and ReOCl3(dpae) confirmed the approximate octahedral environment of the metal and the presence of a Cl ligand trans to the Re=O bond. The ReOCl2(OEt)(L-L) compounds contain a transO=Re-OEt unit. The visible spectra of both types of compounds include a two-component d-d absorption pattern originating from the spin-allowed excitation of a d electron from the interaxial d orbital in the equatorial plane to the empty dxz and dyz orbitals. For ReOCl 2(OEt)(dppf), these bands are masked by strong transitions taking place in the ferrocene moiety. The absorptions of the other systems are not greatly displaced compared to the similar dppe compounds, a small decrease in the transition energy being noted for the dpae complex.
New Complexes of Rhenium-(V) or -(III) with Various Diphosphines or Bis(diphenylphosphino)methane Monoxide: Crystal Structure of mer-
Fontaine, Xavier L. R.,Fowles, Edmund H.,Layzell, Timothy P.,Shaw, Bernard L.,Thornton-Pett, Mark
, p. 1519 - 1524 (2007/10/02)
Treatment of or with the diphosphines, Ph2PCH2PPh2 (dppm), Ph2PC(=CH2)PPh2 (vdpp), cis-Ph2PCH=CHPPh2 (dppen), or Ph2PCHMePPh2 (1,1'-dppe) gave complexes of the type (L-L = chelating diphosphine, X=Cl or Br), in high yield.Treatment of with an excess of dppm at 20 deg C caused some reduction to give a mixture of two rhenium(III) complexes 2a and 3a, which was difficult to separate.Treatment of with 2 mol of dppm in hot benzene gave pure 2a, whilst treatment of with 4-5 mol equivalents of dppm in hot benzene gave 3a in excellent yield.The tribromide analogue was prepared by heating with dppm.On treating with dppm, was formed but this was contaminated with the isomeric salt Br from which it could not be separated; however the NMR parameters for both components were assigned.The pure salt BPh4 was prepared from the mixture.In their 1H NMR spectra, these rhenium(III) complexes show large paramagnetic shifts for the methylene protons of the chelated dppm and for some of the ortho-large paramagnetic shifts for the methylene protons of the chelated dppm and for some of the ortho-protons.Some of these resonances were assigned using two-dimensional correlation spectroscopy and nuclear Overhauser effect experiments.Crystals of complex 2a are monoclinic, space group P21/n, with a=1147.7(4), b=2315.5(6), c=2069.7(6) pm, β=91.7(3) deg and Z=4; final R factor 0.0465 for 6150 observed reflections.The structure shows octahedral co-ordination with a mer arrangement of chlorines, a chelated dppm and a monodentate dppm monoxide, with the P=O group unco-ordinated.
Synthesis and structural studies of some new rhenium phosphine heptahydride complexes. Evidence for classical structures in solution
Luo, Xiao-Liang,Crabtree, Robert H.
, p. 4813 - 4821 (2007/10/02)
A series of new rhenium phosphine heptahydride complexes ReH7L2 (L2 = a chelating bidentate phosphine) have been synthesized and characterized by IR and 1H, 31P, and 13C NMR spectroscopy. The hydride resonances of ReH7(dppf) (1,dppf = 1,1'-bis(diphenylphosphino)ferrocene), ReH7dppb) (2, dppb = 1,4-bis(diphenylphosphino)butane),and ReH7(+)-diop| (3, (+)-diop = (4S,5S)-4,5-bis((diphenylphosphino)methyl)-2,2-dimethyl-1,3-dioxolane) undergo decoalescence upon cooling. The low-temperature hydride patterns suggest classical 9-coordinate tricapped trigonal prismatic structures. Consistent with the classical structures, 1H NMR spectra of deuterated ReH7L2 complexes show very small and temperature-independent upfield isotope shifts in the hydride region and no change in VHP- Sequential treatment of 1, 2, and 3 with NaH and Mc2SO4 in the presence of Ph3SiH leads to ReH6(SiPh3)L2 (L2 = dppf, dppb, (+)-diop). Variable-temperature 1H NMR studies of these silyl derivatives provide further support for the classical formulation of their parent heptahydrides. Theoretical 7, (min) values are calculated for some polyhydrides on the basis of different structural models and are compared with the experimental numbers. Precautions to be taken in interpreting T1 data are discussed.
