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ortho ‐Metalation of Triarylphosphane at Cobalt and Template Synthesis of Chelating 2‐(Diarylphosphanyl)aroyl Ligands
Author(s) -
Klein HansFriedrich,
Schneider Sven,
He Mengzhen,
Floerke Ulrich,
Haupt HansJuergen
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200010)2000:10<2295::aid-ejic2295>3.0.co;2-c
Subject(s) - chemistry , metallacycle , metalation , oxidative addition , ligand (biochemistry) , ring (chemistry) , cobalt , chelation , medicinal chemistry , stereochemistry , catalysis , inorganic chemistry , organic chemistry , x ray crystallography , biochemistry , physics , receptor , diffraction , optics
Elimination of methane from thermally labile CoMe(PPh 3 )(PMe 3 ) 3 generates ortho ‐metalated Co(2‐Ph 2 PC 6 H 4 )(PMe 3 ) 3 ( 1 ). Addition of dihydrogen causes ring‐opening which is followed by a ligand dismutation reaction giving CoH(PMe 3 ) 4 and CoH(PMe 3 ) 2 (PPh 3 ) 2 . The system does not catalytically hydrogenate olefins. CO insertion into the Co−C bond of 1 results in ring expansion and constitutes a template synthesis of the anionic 2‐phosphanylbenzoyl chelate ligand as shown in the molecular structure of Co(2‐Ph 2 PC 6 H 4 CO)(CO)(PMe 3 ) 2 ( 3 ). Oxidative addition of iodomethane transforms 1 into diamagnetic CoMeI(2‐Ph 2 PC 6 H 4 )(PMe 3 ) 2 ( 7 ), while benzoyl chloride oxidizes 1 to paramagnetic CoCl(2‐Ph 2 PC 6 H 4 )(PMe 3 ) 2 ( 8 ). The preservation of the four‐membered metallacycle in three successive oxidation states is supported by single‐crystal X‐ray analyses of 1 , 7 , and 8 .