Two Schiff Base Ligands Derived from 1,2-Diaminocyclohexane

The crystal structures of the free ligands 2,2′-[(1,2-cyclohexanediyl)bis(nitrilomethylidyne)]bisphenol, C₂₀H₂₂N₂O₂, (I), and 2,2′-[(1,2-cyclohexanediyl)bis(nitriloethylidyne)]bisphenol, C₂₂H₂₆N₂O₂, (II), have been determined. In both molecules the N-O distances are indicative of intramolecular hydrogen bonding. In compound (I), the two aromatic rings are inclined at an angle of 56.5 (1)° and the O...O separation is 6.082 (3) Å; in compound (II) the corresponding values are 83.15 (8)° and 5.544 (5) Å. Thus, it is evident that the methyl groups in (II) have a very significant effect upon the overall conformation.

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