| Abstract
| - Stereomerically pure complexes of Rh, Ir, Co, and Mo containing the chiral, menthyl-substituted indenyl ligands (−)-2-menthylindene and (−)-2-menthyl-4,7-dimethylindene formed by metathetic and transmetalation reactions are described. The energy barriers for rotation of ethylene along the metal−indenyl and metal−ethylene axes were determined by variable-temperature 1H NMR.
- Optically active complexes of Rh, Ir, Co, and Mo containing the chiral, menthyl-substitutedindenyl ligands (−)-2-menthylindene and (−)-2-menthyl-4,7-dimethylindene are described.Metathetic reaction of the chiral lithium salts of these indenyl systems (1, 2) with theappropriate starting materials of Rh and Ir yielded the complexes (−)-(2-menthylindenyl)Rh(COD) (3), (−)-(2-menthyl-4,7-dimethylindenyl)Rh(COD) (4), (−)-(2-menthylindenyl)Rh(C2H4)2 (5), (−)-(2-menthyl-4,7-dimethylindenyl)Rh(C2H4)2 (6), (−)-(2-menthylindenyl)Ir(COD)(7), (−)-(2-menthylindenyl)Ir(C2H4)2 (8), (−)-(2-menthyl-4,7-dimethylindenyl)Ir(C2H4)2 (9),and (−)-(2-menthyl-4,7-dimethylindenyl)Ir(COE)2 (10). Co2(CO)8 and CoCl2(dppe) reactwith (−)-2-menthylindenyllithium (1) yielding (−)-(2-menthylindenyl)Co(CO)2 (11) and(+)-(2-menthylindenyl)Co(dppe) (12). (−)-Li[(2-menthylindenyl)Mo(CO)3](THF)2 (13), formedby transmetalation of Mo(CO)6, is oxidized by I2, yielding (−)-(2-menthylindenyl)Mo(CO)3I(14), or by allylic chloride, yielding (allyl)(2-menthylindenyl)Mo(CO)2 (15). All compoundswere formed stereomerically pure and were obtained after chromatography by dried aluminaunder nitrogen. The structures of 3, 4, 6, 7, and 14 were determined by single-crystal X-raydiffractometry. Variable temperature 1H NMR spectra of 5, 6, 8, and 9 were recorded todetermine the energy barriers for rotation of ethylene along the metal−indenyl and metal−ethylene axes.
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