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Optically active transition metal complexes, LXXI *) . synthesis, characterization, and conformational analysis of pyridine‐imine complexes [C 5 H 5 (CO) 2 MoNC 5 H 4 CX=NCH (R 1 ) (R 2 )]PF 2 with X = H, CH 3 , and C 6 H 5

1980; Wiley; Volume: 89; Issue: 10 Linguagem: Inglês

10.1002/bscb.19800891014

0037-9646

Henri Brunner, D. K. RASTOGI,

Organometallic Complex Synthesis and Catalysis

Abstract Six new complexes of the type [C 5 H 5 Mo(CO) 2 NN*]PF 6 have been prepared by treatment of C 5 H 5 Mo (CO) 3 Cl with the Schiff bases NN * , derived from 2‐acetyl pyridine or 2‐benzoyl pyridine and chiral amines H 2 NCH(R 1 ) (R 2 ) with (R 1 ) (R 2 ) = (CH 3 )‐(C 6 H 5 ); (C 2 H 5 ) (C 2 H 5 ), and (CH 3 ) (C 2 H 5 ). The Schiff bases NN * contain a chiral amine component in its racemic form (R')/(S'). Therefore, in combination with the Mo chirality (R) and (S) a mixture of diastereoisomeric pairs of enantiomers (RS′)/(SR') and (SS')/(RR') is obtained. The diastereoisomers are separated by fractional crystallization. Diastereoisomer equilibration was achieved by heating the compounds in acetone‐d 6 at 80°C for 90 h. The diastereoisomers have been differentiated on the basis of their 1 H NMR spectra. A conformational analysis in terms of a) chemical shift difference for the C 5 H 5 signals and b) ratio of diastereoisomers at equilibrium indicates how the chiral carbon substituents arrange with respect to the ligand plane for the diastereoisomers differing at the Mo configuration.