Determination of stability constants of intermediates by coordination capillary GLC. Chiral complexes of NiII and CuII with Schiff's bases (1R, 2R)-N,N′-bis(3′-tert-butylsalycilidene)diaminocyclohexane and (1R,2R)-N,N′-bis[(4-hydroxy[2.2]paracyclophanyl)-5-methylene]diaminocyclohexane as GLC phases

Chiral NiII and CuII salen complexes dissolved in the polymethylphenylsiloxane phase OV-17 were used as the phases for capillary chromatography. Chiral salen lignads are Schiff's bases obtained from salicylaldehyde (SA) and (1R,2R)-diaminocyclohexane and Schiff's bases obtained by condensation of (1R,2R)- or (1S,2S)-diaminocyclohexane with (R)-4-hydroxy-5-formyl[2.2]paracyclophane (HFPC). The stability constants of the intermediates were calculated from the retention times. The complexes based on HFPC are stronger Lewis acids than those based on SA. The ability of the substrates to form intermediates decreases in the sequence: aromatic aldehydes>halogen-substituted aromatic compounds>halogen-substituted aliphatic compounds.