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Transition‐Metal Complexes of the Optically Active Cyclopentadienyl Ligand PinCp*: Crystal Structure of ( S Re )‐(η 5 ‐PinCp*)Re(NO)(PPh 3 )[CONHCH(CH 3 )C 10 H 7 ]
Author(s) -
Salzer Albrecht,
Hosang Annegret,
Knuppertz Jutta,
Englert Ulli
Publication year - 1999
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/(sici)1099-0682(199909)1999:9<1497::aid-ejic1497>3.0.co;2-6
Subject(s) - chemistry , diastereomer , cyclopentadienyl complex , sodium methoxide , ligand (biochemistry) , medicinal chemistry , amide , crystal structure , trimethylsilyl , amine gas treating , stereochemistry , crystallography , methanol , organic chemistry , catalysis , biochemistry , receptor
The synthesis of (η 5 ‐PinCp*)Re(CO) 3 [PinCp* = tetramethyl(pinanyl)cyclopentadienyl] is described. Successive substitution of two CO ligands by NO + and PPh 3 generates a 1:1 diastereomeric mixture of chiral‐at‐metal [( S Re )/( R Re )‐(PinCp*)Re(CO)(NO)(PPh 3 )]BF 4 . The diastereomers are converted with sodium methoxide into the derivative “esters” ( S Re )/( R Re )‐(PinCp*)Re(COOCH 3 )(NO)(PPh 3 ), and then with (+)‐( R )‐(1‐naphthylethyl)amine to the “amides” ( S Re )/( R Re )‐(PinCp*)Re(NO)(PPh 3 )[CONHCH(CH 3 )C 10 H 7 ] [( S Re )/( R Re ) = 1:1]. Fractional crystallisation separates the ( S Re ) isomer with an optical purity of > 98%. The latter compound has been characterized by X‐ray structure analysis. By treating the ( S Re )‐amide with CF 3 CO 2 H and NaBF 4 , ( S Re )‐(PinCp*)Re(CH 3 )(NO)(PPh 3 ) can be generated. Protolysis of this compound with HBF 4 /Et 2 O in CD 2 Cl 2 at –78 °C leads to the solvent‐stabilized complex ( S Re )‐[(PinCp*)Re(NO)(PPh 3 )(ClCD 2 Cl)] + BF 4 − . The thermal and configurational stability of this chiral Lewis acid is investigated at various temperatures. The syntheses of [PinCp*RhCl 2 ] 2 , PinCp*TiCl 3 and PinCp*M(CO) 2 (NO) (M = Mo, W) are also described. Starting with PinCp*M(CO) 2 (NO), the relatively stable 16‐VE complexes PinCp*MCl 2 (NO) and PinCp*W(CH 2 SiMe 3 ) 2 (NO) are synthesized.