SYNTHESIS AND STRUCTURAL STUDY OF A NOVEL NONLINEAR-OPTICAL MATERIAL - THE TOLANE DERIVATIVE ETHYL BENZYLOXYPHENYLETHYNYL)-5-NITROBENZENE-1-CARBAMATE

We have synthesized the tolane derivative ethyl benzyloxyphenylethynyl )-5-nitrobenzene-1-carbamate 1, a promising material for nonlinear opt ics. Compound 1 has several crystal forms and we have characterized th eir structural properties by X-ray diffraction. One of the three forms , which is crystallized from a strong polar solvent, has a non-centros ymmetric structure and is ca. ten limes as strong a second-harmonics g enerator as meta-nitroaniline. A hydrogen bond is found to perform an important role in forming the non-centrosymmetric geometry, which is n ecessary for a nonlinear optical crystal.