Induced circular dichroism in achiral and racemic chiral complexes

Abstract EN

Induced Circular Dichroism (CD) in a number of symmetric complexes such as [Cr(NH3)6]3+, [Ni(NH3)4]2+, [Ni(NH3)6]2+, [Co(NH3)4C12]+, and racemic dissym-metric complexes like [Co(en3]3+, [Ni(en)3]2+, [Cr(en)3J3+ in the presence of L(+) tartaric acid (2.5 M) solution are reported and explained on the basis of outer-sphere complexation via hydrogen bonding mechanism.

A number of the complexes such as [Ni(NH3)J2+, [Ni(NH3)4]2+ c،5-[Co(NH3)3]2+, [Ni(en)2]2+, though similar to [Co(NH3)6J3+, or [Co(en)3]3+ , do not show induced CD bands in the visible region in the presence of L(+) tartaric acid.

These observations indicate that hydrogen bonding is not the only mechanism for outer-space complexation in many systems.