117227-88-0Relevant academic research and scientific papers
Metallacycle formation through the linking of an alkyne with phosphido and acetyl groups at an iron centre: X-ray structure of (Cp = η5-C5H5)
Adams, Harry,Bailey, Neil A.,Blenkiron, Peter,Morris, Michael J.
, p. 73 - 82 (1993)
The diphenylphosphine ligand of (Cp = η5-C5H5) can be deprotonated with DBU (DBU = 1,8-diazabicycloundec-7-ene) or n-butyllithium; subsequent alkylation with RI (R = Me, Et) gives the complexes . Reaction of the anionic phosphido complex with the electrophilic alkyne methyl propiolate (HCCCO2Me) followed by reprotonation with CH3COOH gives the vinylphosphine complex , whereas a similar reaction sequence with dimethyl acetylenedicarboxylate (DMAD, MeO2CCCCO2Me) produces two isomers of the complex , in which linking of the alkyne with both the phosphido and acetyl ligands has occurred to form a six-membered metallacycle. The structure of one of the two isomers has been determined by X-ray diffraction and shows that the metallacyclic ring is bound to the iron atom through the phosphorus and the carbonyl oxygen of the acetyl group, and adopts a boat conformation in the solid state.
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.
