Synthesis, crystal structures, and optical properties of a novel imidazole derivative and its Zn(II) complex

A novel imidazole derivative, 1-[trans-4-(4-diethylaminostyryl)phenyl]imidazole (abbreviated as L), and its complex Zn(SCN)2L2 have been synthesized and fully characterized. Their crystal structures have been determined by X-ray diffraction. The molecular structure of L is approximately coplanar, the bond lengths of C–C and C–N are located between the normal double and single bonds, which show that L has a delocalized π-electron system in the molecule. In the molecular structure of Zn(SCN)2L2, zinc atom is four coordinated by two nitrogen atoms of the ligands (L) and two nitrogen atoms of thiocyanate to form a distorted tetrahedral geometry. The one-dimensional structure of Zn(SCN)2L2 is formed by C–H⋯S interactions and π–π interactions. They both crystallize in the noncentrosymmetric space group P21, and exhibit powder second-harmonic generation (SHG) efficiency approximately twenty times high as that of urea, indicating promising potential applications as useful nonlinear optical (NLO) materials.