Weak absolute helicity direction in Ni–salen by trans-cyclohexane-(1R,2R)-diamine

Helical Ni–salen foldamers were synthesized from enantiomerically pure cyclohexane-(1R,2R)-diamine, N,N′-bis-(N-phenyl (4-diphenylphosphine)-3-salicylidenato carboxamide)-(1R,2R)-cyclohexanediaminato-nickel(II). X-ray structural characterization of the absolute helicities observed confirms our earlier assertions, based on solution spectroscopic evidence, that trans-cyclohexane-diamine, a common component of chiral salen catalysts, is a weak director of absolute helicity for Ni–salen.