Design And Photoelectric Functional Study Of Imidazole-containing Complexes With D-π-A Type

Imidazole-containing complexes have attracted considerable attention for theirpotential applications such as pharmaceutical synthesis, selective catalysis, ionrecognition, nonlinear optics etc. Design and synthesis of functionalimidazole-containing ligands, forming a variety of novel functional supramolecularcompounds by clever supramolecular self-assembly have been receiving increasingattentions in recent years. In this paper, a series of imidazole derivatives with D-Ï€-Atype were synthesized, and many imidazole-containing complexes were alsosynthesized via supra-molecule self-assembly. Main research results in thedissertation were summarized as follows:1. By molecular designing, we synthesized three novel imidazole-containing ligandswith D-Ï€-A type L¹ (1-{trans 3-[4-(N-diethylamino)styryl] benzene} imidazole), L²(1-{trans 3-[4-(N-dihextylamino) styryl] benzene} imidazole), L³ (1-{trans3-[4-(N-diisooctylamino) styryl] benzene}imidazole), which were characterized byIR, ¹H NMR, elemental analysis and electronspray mass spectrometry.2. A series of complexes CdCl₂L₂¹,CdBr₂L₂¹,CdI₂L₂¹,ZnI₂L₂¹,HgBr₂L₂¹,HgI₂L₂¹,COL₄¹Cl₂,ZnL₆¹(PF₆)₂ and CdL₆¹(PF₆)₂ were synthesized, and the structuralcharacteristics of four complexes(CdI₂L₂¹,HgI₂L₂¹,CoL₄¹Cl₂ and HgBr₂L₂¹) havebeen fully detailed by X-ray single crystal diffraction. The results show that the singlecrystals for four complexes belong to triclinic system, P(?) space group, and the metalion in the complexes exhibit four or six coordination modes, and halogen atomsdirectly involved in the coordination. In the complex CdI₂L₂¹, the hydrogen bondsbetween the iodine atoms and hydrogen atom on methyl formed supramolecular gridstructure; In the complex HgI₂L₂¹, the hydrogen bonds between the iodine atoms andhydrogen atom on methylene formed butterfly-shaped structure; The supramolecularcompound formed through C-H…Cl and C-H…πand other weak interactions in thecrystal of complex CoL₄¹Cl₂, while a simple compound formed through C-H…πandother weak interaction in the crystal of complex HgBr₂L₂¹. 3. The thermal stability, linear absorption, one-photon induced emission,two-photon induced emission spectra and electrochemical properties have beeninvestigated. The relationships between structures and properties have been discussedin detail. The results show that hydrogen bonds influence on their luminescentproperties in solid state. Under the same test conditions, two-photon inducedfluorescence of the ligand L¹ and a series of complexes were investigated. The resultsshow that the ligand L¹ have almost no two-photon response, while complexes havestrong two-photon response, which may be due to the induced effect from the metalions. The metal ions make the charge transmitting easier, which will be conducive tostrong two-photon induced fluorescence, consequently. The two-photon absorption(TPA) cross section (s) of these compounds were obtained by using two-photoninduced fluorescence. The investigations show that the series of the complexes havelarge TPA cross section.