Dihydro-imidazole Derivatives, Cobalt, Copper, Silver Complex Synthesis, Structure And Nature Study

In this paper, the eight complexes [Co₂(Bib)₃Cl₂](CH₃COO)₂ 1, .[Co₂(Bib)₃Cl₂](CH₃OH)₂(H₂O)₂Cl₂ 2, [Co₃K (Tib)₃(CH₃COO)₆(]PF₆) 3, [Cu₂ Bio (CH₃COO) ₄] 4, [Co Bio Cl₃] 5, [Ag₂ Bio (NO₃)₂], 6, [Ag(Bio)₂ NO₃] 7,[Ag Bio]BF₄ 8, and tow crystal [H Bio·ClO₃] 9, [H Bio·ClO₄] 10, have been firstly synthesized, in which Bib = 1, 3-bis (4, 5-dihydro-1H-imidazol-2-yl) benzene, Tib = 1, 3, 5-tris (4, 5-dihydro-1H-imidazol-2-yl) benzene, Bio = 9, 10-dihydro-benzo [de]imidazo [2, 1-a] isoquinolin-7-one, respectively, characterized by elemental analysis, infrared spectroscopy, Uv-vis spectroscopy, variable temperature susceptibility and fluorescence spectroscopy, respectively. The results of crystal analysis show that 1, 2 in which the each metal atom is co-ordinated in a tetrahedron geometry of [CoN₃Cl]. The clelate N atoms come from three imine N atoms of dihydrogen imidazoles and Cl atoms from cobalt cloride, respectively. In complex 3, each Co²⁺ is co-ordinated in a octahedron geometry of [CoN₂O₂]. The clelate N atoms come from three imine N atoms of dihydrogen imidazoles and O atoms from acetate groups, respectively.In complex 4～8, the ligand Bio present various chelate ways. The results of crystal structures express that complex 4 is also coordinated in a tetrahedron geometry of [CoNCl₃] with mononuclear. In complexe 5, two Cu (II) ions bridged with four acetate groups form a dinuclear molecule structure. Complex 6 whose central atom is silver is a one-dimensional chain of zigzag while complex 7 and 8 are all mononuclear silver complexes.The results frpm the UV spectrum of the methanol solutions of Bib, Tib and complex 1～3 indicates that there appears a strong wide absorption peak at 260 nm which is due to the transition ofÏ€â†'Ï€^* in benzene ring and it exists in all the ligands and complexes. There is also a shoulder peak that can be indexed as the transition ofÏ€â†'Ï€^* in imine at 310nm. The weak peaks at, 580nm and 620nm in the complex 1～3 are caused by the d-d transition of the spin electron in Co²⁺. From the UV spectrum of the methylene chloride solutions of Bio and complex 6～8 and 10, it can be learned that there exist three groups of peaks which are alike in outline in the range from 200nm to 400nm. These can belong to theÏ€â†'Ï€^* transition of the conjugate ring.The results of variable temperature susceptibility indicate complex 1 and 3 possess antiferromagnetic property in temperature from 2 to 300 K, follow the Curie–Weiss law with a Weiss constantθ-11.25 K, -84.15 K in temperature from 50 to 300 K respectively, whereas 2 behaves antiferromagnetic property in temperature from 20 to 300 K, which follows the Curie–Weiss law with a Weiss constantθof -12.13 K, ferimagnetic property in low temperature from 2 to 20 K, TN is 6 K. Under 2K, 2 shows the magnetization versus field hysteresis loops and frequency dependence of these transitions is observed, which indicate complex 2 is single molecule magnets (SMMS). The blue-green light of complex 4, 6¹0 caused by photoluminescence has been observed in the solid state. The one-dimensional zigzag chain in complex 6 can enhance its intensity of photoluminescent,λ_em=477nm.