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Tris‐Chelating Oxygen Ligands: New Synthetic Routes to Sterically Demanding Ligands
Author(s) -
Kläui Wolfgang,
Schramm Georg,
Asbahr HarkOluf,
Englert Ulli
Publication year - 1997
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19971300909
Subject(s) - chemistry , ligand (biochemistry) , steric effects , medicinal chemistry , cyclopentadienyl complex , sodium hydride , hydride , lithium (medication) , sodium , tris , alkali metal , metal , oxygen , chelation , coordination sphere , yield (engineering) , stereochemistry , inorganic chemistry , crystallography , crystal structure , organic chemistry , catalysis , receptor , medicine , biochemistry , endocrinology , materials science , metallurgy
The lithium and sodium compounds A[P(O)R 2 ] (A + = Li + , Na + ; R = OPh, O i Pr) have been prepared in situ from Hp(O)R 2 and butyllithium or sodium hydride. They react with the cyclopentadienyl complexes [(C 5 H 5 )MI 2 (CO)] (M = Co, Rh), [(C 5 Me 5 )CoCl 2 ] 2 , and [(C 5 H 5 )CoI 2 ] n to yield alkali metal salts AL of tridentate oxygen ligands (A + = Li + , Na + ; L − = [(C 5 R′ 5 ]M{P(O)R 2 } 3 ] − , R′ = H, Me; M = Co, Rh; R = OPh, O i Pr) ( 2 ). For the ligand L Co, OPh = [(C 5 H 5 )‐Co{P(O)(OPh) 2 } 3 ] − , an alternative synthesis has been developed, starting from [(C 5 H 5 ) 2 Co]PF 6 . The structure of the sodium salt NaL Co, OPh ( 2d ) has been determined by X‐ray diffraction. The ligand L Co, Oph − , with a cone angle TH of about 200°, completely blocks one half of the coordination sphere around the sodium centre. The ligand profile has been calculated to allow appraisal of the angular encumbrance of the ligand.