Design, Synthesis, Structure And Properties Of Heterometallic Polynuclear Oxamido-bridged Complexes

Rational design and construction of novel oxamido-bridged coordination polymers, and investigation of their properties are the current interest in the field of crystal engineering and superamolecular chemistry, stemming from their various intriguing molecular topologies and potential applications as functional materials. A successful strategy to construct high-nuclearity and high-dimensionality oxamido-bridged coordination compounds is the introduction of additional functional groups into the oxamido-bridged ligands, because these groups not only can effectively improve these conditions to a certain extent, but also can form many new complexes with novel functionalities.In this paper, we investigated the synthesis, characterization, single-crystal structures and properties of three kinds of oxamido-bridged ligands, copper(â…¡) mononuclear complexes and their polynuclear complexes. The main contents are described as following:(1) Through condensing N-(2- benzaldehyde)oxamic acid ethyl ester, methyl carbazate and ethanolamine, two new oxamidate schiff base ligand EtH₂oxce (EtH₂OXce = N-(2-imino methyl carbazate benzaldehyde) oxamic acid ethyl ester) and H₃Oxba(H₃Oxba = N-(2-benzaldehyde methyl carbazate)-N'-(2- hydroxyethyl) oxalamide have been synthesized. Using their CuL precursor Na[Cu(oxae)H₂O]·H₂O and Na[Cu(oxba)]·2H₂O as buiding block we have obtained Cu(â…¡)-M(â…¡)( M=Mn, Co) heterotrinuclear complexes. Their crystal structure have been determined by X-ray analysis. Complexes show strong fluorescence emission as well as their free ligands. The magnetic coupling are strongly antiferromagnetic.(2) The Thiosemicarbazone ligand EtH₂obte (EtH₂obte = N-(2-benzaldehyde thiosemicarbazone) oxamic acid ethyl ester, DMF = dimethylformamide)was synthesized from N-(2-benzaldehyde) oxamic acid ethyl ester and thiosemicarbazide. Using its mononuclear complex Na[Cu(obte)]·2H₂O with transitional metal ions Mn(â…¡), Cd(â…¡) respectively, we have gotten two complexes: [Cu(obte)]₂M(DMF)₂ (M=Mn(â…¡), Cd (â…¡)), we reported the crystal structure, thermal decomposition mechanism and antitumor studies. The ligand and its complexes show strong fluorescent emission.(3) Using condensing 2-Aminotherephthalic acid, oxalyl chloride and Cu(CH₃COO)₂·H₂O, We prepared mononuclear complex Na₄[Cu(atox)]·2H₂O, Under the conditions of hydrothermal sysnthesis, through the self-assembly of mononuclear complex with the mixture of mental salt (Zn(CH₃COO)₂·2H₂O, Mn(CH₃COO)₂·4H₂O, NaNO₃), four polynuclear complexes with one-, two-dimensional (1D, 2D) structures were obtained. We studied their spectacular structures and properties.