Structural basis for the absence of thermal mesomorphism in p-[(p-methoxybenzylidene)amino]phenol

Abstract

The crystal structure of the title compound (2) has been determined in order to establish the role of hydrogen-bond formation in inhibiting thermal mesomorphism. Hydrogen bonds link the molecules in the crystal in infinite interlocking zig-zag chains with the terminal hydroxy-groups acting as donors and the central nitrogen atoms as acceptors (O–H ⋯ N 2.756 Å). The angles between the long molecular axes in the chains are alternately 70 and 110°, and the overall molecular packing is of the herring-bone type and unsuited to mesophase formation.

Crystals conform to space group P2₁/n with a= 11.375(5), b= 17.307(8), c= 6.007(4)Å, β= 92.23(3)°, and Z= 4. The structure was solved by dirct methods, and least-squares refinement yielded R 0.043 for 1 421 independent significant reflections measured by counter diffractometry.