STRUCTURAL BASIS FOR ABSENCE OF THERMAL MESOMORPHISM IN PARA-[(P-METHOXYBENZYLIDENE)AMINO]PHENOL

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 P2 1/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 direct methods, and least-squares refinement yielded R 0.043 for 1 421 independent significant reflections measured by counter diffractometry.