Crystal structure of 2-(4-(diphenylamino)benzylidene)malononitrile, C22H15N3

Abstract

Source of material 2-(4-(Diphenylamino)benzylidene)malononitrile was prepared through the Knoevenagel condensation of 4-formyltriphenylamine and malononitrile. Chemicals used for the synthesis were commercially available, were of AR grade, and were used as received without further purification. Amixture of the trilphenylamine (273 mg, 1mmmol) and malononitrile (73 mg, 1.1 mmol) was dissolved in n-butanol 15mL. The mixture was stirred and heated to reflux. After 4h,the mixture was cooled down to room temperature. After the solvent was evaporated, the residual was purified by chromatography (CH 2 Cl 2 /hexane, 2:1) to yield cyanovinylene 305 mg (90 %) as an orange solid. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of its solution in hexane at room temperature. Experimental detailsSingle crystal X-ray diffraction data of the compound was collected on an ADSC Quantum210 detector at Beamline 4A MXW of Pohang Light Source. DiscussionThe title compound was synthesized as asolid fluorescence material. And some papers have reported it as an excellent organic functional materials extensively [1,2]. In the title crystal structure the phenyl ring C13-C18 is planar. The two −C≡Ng roups are in another plane ( figure, top). The mean plane of two C≡Ngroups bonded to C20 is slightly twisted out of the phenyl ring C13-C18 making ad ihedral angle of 9.50(6)°.The packing of molecules in the unit cell shows avery interesting pattern. The conformation of the three phenyl rings C1-C6, C7-C12, and C13-C18 connected to N1 is like the blades of apropeller making N1 achiral center and the dihedral angles between the three phenyl rings are 70.05(1)°,7 2.667(3)°,a nd 74.16(3)°,respectively. Four molecules including two left-hand and two right-hand spirals connected together head-to-tail in unit cell making the whole structure achiral. Molecules do not form intra-or inter-molecular hydrogen bonds. Other less unusual interactions, are p C=C···p and pN≡C···p interactions (figure, bottom). Because C19−H15···p interactions are observed every second layer, the distance between adjacent layers is different. The distance are 3.169 Å and 3.644 Å,respectively. Between any two layers, double bond (C19=C20) and triple bond (C22≡N2) interact with the phenyl ring C13-18 except C21≡N3.