Alignment of PHTP–DNAA inclusion crystals by zone casting

Abstract Inclusion compound of perhydrotriphenylene (PHTP) and polar N,N-dimethyl-4(4-nitrophenylazo)-aniline was grown from solution into oriented crystalline layers using a zone casting technique. The parallel orientation of channel axes in the direction of the casting was investigated by means of a combination of optical absorption, polarized visible light and a pronounced SHG response. The maximum of the SHG signal of an oriented needle-like crystal was observed along the channel axis. A phase sensitive second harmonic generation (PS-SHG) experiment has demonstrated a bi-polar state of PHTP/DNAA growth from solution. Experimental evidence is provided, that unipolar layers can be obtained.