Controlling the crystal morphology of one-dimensional tunnel structures: induced crystallization of alkane urea inclusion compounds as hexagonal flatplates

We propose a general strategy for controlling the crystal morphology of tun nel inclusion compounds in order to induce crystal growth as flat plates ra ther than long needles. The strategy employs additive molecules designed to selectively inhibit crystal growth along the tunnel direction. The success ful application of this strategy is illustrated by the induced crystallizat ion of alkane/urea inclusion compounds as hexagonal flat-plate crystals usi ng 5-octadecyloxyisophthalic acid as the selective crystal growth inhibitor (in the absence of inhibitor, alkane/urea crystals grow spontaneously as l ong hexagonal needles). (C) 1999 Elsevier Science B.V. All rights reserved.