85185-81-5Relevant academic research and scientific papers
Phosphorus-phosphorus coupling constants in mixed-phosphine tricarbonyl iron complexes, Fe(CO)3LL′. Crystal structure of trans-Fe(CO)3(PEt3) (PPh3)
Keiter, Richard L.,Benson, John William,Keiter, Ellen A.,Harris, Travis A.,Hayner, Matthew W.,Mosimann, Laura L.,Karch, Eric E.,Boecker, Carol A.,Olson, Donna M.,Vanderveen, Jennaver,Brandt, Douglas E.,Rheingold, Arnold L.,Yap, Glenn P.A.
, p. 2246 - 2253 (2008/10/08)
Mixed-ligand complexes, trans-Fe(CO)3LL' (L = PPh2Me, L' = PPh2Me, PPhMe2, PMe3, PPh2-Et, PEt3, PPh2CH=CH2, PPh2H, AsPh3, P(OPh)3; L = PMe3, L' = PEt3, PPh2Et, PCy3, PPh2Me, PPhMe; L = PEt3, L' = PPh2Me; L = PPh2H, L' = PPh2CH=CH2, PPh2Et; L = AsPh3, L' = PPhMe2, P(OPh)3, P(OMe)3, P(OEt)3), have been obtained from the stepwise reaction of phosphines with Fe(CO)3(BDA) (BDA = benzylideneacetone) or Fe(CO)3(AsPh3)2 and from the reaction of phosphine with Fe(CO)4PPh3 in the presence of base. A strong negative correlation exists between 2Jpp coupling constant values and the sum of the phosphine pKa values. By application of quantitative analysis of ligand effects, it has been shown that 2Jpp for the mixed-ligand complexes correlates strongly with both γ and Ear, but not with θ. Although a near perfect fit is obtained from the three-parameter equation, a statistical analysis suggests that for this small data set there are no predictive advantages over the one-parameter pKa model. It is possible to calculate reliable 2Jpp values for transFe(CO)3L2 complexes with either model. An X-ray structure of solid-state frans-Fe(CO)3-(PEt3)(PPh3) shows equal Fe-PEt3 and Fe-PPh3 bond distances, implying that bond strength equalization may occur when two rather different phosphines occupy trans coordination sites.
Heterobimetallic phosphido-bridged complexes containing coordinatively unsaturated rhodium(I) and iridium(I) centers. Structural characterization of FeIr(μ-PPh2)(CO)5(PPh3)2
Roberts, David A.,Steinmetz, Guy R.,Breen, Michael J.,Shulman, Peter M.,Morrison, Eric D.,Duttera, Michael R.,DeBrosse,Whittle, Robert R.,Geoffroy, Gregory L.
, p. 846 - 855 (2008/10/08)
The series of new phosphido-bridged heterometallic binuclear complexes FeM(μ-PPh2)(CO)x(L)2 (M = Rh, L = PEt3, x = 4, 5; M = Ir, L = PPh3, x = 4-6) have been synthesized by the reaction of Li[Fe-(CO)4(PPh2)] with the appropriate irans-MCl(CO)L2 complex. The new complexes have been characterized spectroscopically, and FeIr(μ-PPh2)(CO)5(PPh3)2 has been characterized by a complete single-crystal X-ray diffraction study. It crystallizes in the space group P1 with a = 11.681 (3) A?, b = 20.869 (4) A?, c = 10.649 (9) A?, α = 96.74 (3)°, β = 108.86 (3)°, γ = 76.51 (2)°, V = 2386 (3) A?3, and Z = 2. Diffraction data (0° ≤ 2θ ≤ 50°) were collected with an Enraf-Nonius CAD4 automated diffractometer, using graphite-monochromatized Mo Kα radiation, and the structure was refined to R = 0.053 and Rw = 0.077 for 6257 independent reflections with I ≥ 3.0σ(I). The μ-PPh2 ligand bridges the Fe and Ir atoms, and each metal is ligated by a PPh3 ligand. The Fe is further ligated by three CO's and the Ir by two. The relatively long Fe-Ir bond length of 2.960 (1) A? suggests a weak donor-acceptor type interaction between the two metal centers. Each of the new compounds undergoes a series of reversible addition/elimination reactions with CO, and the Fe-Ir compounds react with H2 to give new H2 adducts.
