Optical activity of characteristic vibrational modes and absolute configuration

Abstract

The observed vibrational circular dichroism (c.d.) due to the symmetric and the antisymmetric N–H stretching modes of (R)-(+)- and (S)-(–)-2,2′-diamino-1,1′-binaphthyl originates principally from non-degenerate chromophore-substituent coupling and not from the degenerate coupling mechanism particular to dissymmetric dimers; the general non-degenerate mechanism provides a procedure for the determination of absolute configuration from the c.d. associated with a localised characteristic vibrational mode.