Au(i)-benzimidazole/imidazole complexes. Liquid crystals and nanomaterials

Abstract

Three series of Au(I)-imidazole complexes with stoichiometries of [Au(C_n-bim)Cl], [Au(C_n-im)Cl], and [Au(C_n-im)₂][NO₃]·2H₂O (C_n-bim = N–C_nH_2n+1-substituted benzimidazole and C_n-im = N–C_nH_2n+1-substituted imidazole) together with the compound of [Au(C₁₈-bim)₂][NO₃] are synthesiszed. Typical structures of each series are determined by single crystal X-ray diffraction. The last series of compounds, are liquid crystals, and exhibit a wider mesophase range than their Ag(I) analogues. These Au(I) complexes form Au nanostructures both through chemical reduction or thermolysis. For the first time, N-long chain imidazole is utilized to stabilize colloidal Au in solution. Also for the first time, unique examples of simple thermolysis to produce large Au plates of nanothickness are demonstrated. Formation of a plate-like morphology through fusion of sphere-like nanoparticles at an early stage is evidenced by TEM images.