59140-17-9Relevant academic research and scientific papers
Separation of phosphorus(III) ligands into pure σ-donors and σ-donor/π-acceptors: Comparison of basicity and σ-donicity
Rahman, Md. Matiur,Liu, Hong-Ye,Eriks, Klaas,Prock, Alfred,Giering, Warren P.
, p. 1 - 7 (2008/10/08)
The separation of phosphorus(III) ligands into two distinct groups identified as pure σ-donor ligands and σ-donor/π-acceptor ligands for the acetyl and methyl complexes, (η-Cp)FeL(CO)COMe, (η-Cp′)FeL-(CO)COMe (Cp′ = MeC5H4), and (η-Cp)FeL(CO)Me, is accomplished by correlation of the terminal carbonyl stretching frequencies with the EL°′ values. The basicity (pKa value of HPR3+) is related primarily to the σ-donicity (the ability of a ligand to donate σ-electrons to a transition metal) and to a lesser degree to the size of the ligand. We conclude that pKa values are reasonable measures of the σ-donicity for those ligands that are pure σ-donor ligands; a better measure are the χ values for those ligands that are pure σ-donors for both the iron complex and LNi(CO)3.
