130102-27-1Relevant 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.
Preparation and characterization by 31P-NMR spectroscopy of mixed disubstituted complexes
Bellachioma, Gianfranco,Cardaci, Giuseppe,Macchioni, Alceo,Reichenbach, Gustavo
, p. 367 - 376 (2007/10/02)
The disubstituted complexes , where L and L' are different phosphine ligands have been prepared by reaction of the hydrosilyl derivatives with L'.Good results were obtained for L = PMe3 and L' = PPh3, P(OPh)3, P(OEt)3 or P(O-i-Pr)3 but with L' = PMe2Ph, PMePh2, PEt3, a mixture of homo and mixed disubstituted derivatives were obtained.The results can be interpreted in terms of exchange of the L ligand in 3 with L'.The variations in the 31P NMR chemical shifts and 2JPP coupling constants are discussed in the light of the properties of the ligands, and good correlations are revealed with the cone angle and the pKa, respectively.
