Syntheses, Structures And Properties Of Coordination Complexes Supported By Derivatives Of Carboxylic Acid

In recent years, the design and construction of coordination complexes by assembly of metal ions with multidentate ligands have attracted considerable attentions. This is due to their intriguing structural topologies and their potentials for use as functional materials in fluorescence, catalysis, adsorption, nonlinear optics and magnetism. We are interested in the construction, chemical and physical properties of coordination polymers derived from hydroxamic acids. In this thesis, based on ligands benzohydroxamic acid (bhaH2), and4-aminophenyl hydroxamic acid (4-AphaH), a series of trasition metal complexes were obtained. The luminescence properties, magnetic properties etc. were investigated on the basis of their corresponding structures. These results were briefly described as follows:1. The reactions of metal salts and bhaH2,4-AphaH gave rise to five coordination complexes:[CoⅢ2(4-APha)4Cl2](1)[NiⅡ2(4-APha)4(H2O)2](2)[CoⅡ2(4-APha)4(H2O)2](3)[NiⅡ3(bhaH)2(bipy)2(Ac)4](4)[CoⅡ3(bhaH)2(phen)2(Ac)2(BA)2](5)Complexes1-3exhibit the similar dinuclear structures, and each metal center displays octahedral coordination environments. In trinuclear complexes3and4, each hydroxamate bridge is in the η2-η1-η2mode.2. The reaction of metal salts, bhaH2and4-AphaH yielded five polymers:[CdⅡ(4-APha)2]n(6){[Zn8Ⅱ(4-APha)8(Ac)8]·2CH3CH2OH}n (7){[ZnⅡCoⅡ(bhaH)2(Ac)2]·2CH3CH2OH}n (8){[MnⅡ(bhaH)2]·2CH3OH}n (9) Polymers6,7,9exhibit one-dimensional chain structures, while complex8displays a three-dimensional network. Strong red fluorescence emissions are observed for complexes6and7at solid state. Variable-temperature solid-state dc magnetic susceptibility studies have been performed in the temperature range of2-300K for complex9and antiferromagnetic exchange interactions were found.3. The reaction of metal salts and bhaH2produced four novel high-nuclear clusters:[CoⅡ16O(OH)2(bha)12(PhCO2)4(Phen)2(MeOH)4]·2MeOH (10)[ZnⅡ13(bha)8(bhaH)6(AC)4]·4H2O (11)[NiⅡ5ZnⅡ8(bha)8(bhaH)6(AC)4]·4CH3CH2OH (12)[CoⅡ5ZnⅡ8(bha)8(bhaH)6(BA)4]·4CH3OH·2H2O (13).The Co16cluster (10) can be thought of as a face-centered cubic with two wings. The hydroximate ligands in10display three distinct binding modes, one of which is novel. In cluster11, the thirteen zinc ions are in octahedral coordination environments, with distorted square pyramidal geometry. In12and13, the five zinc ions have the octahedral coordination environments, and the eight nickel/cobalt ions exhibit the distorted square pyramidal geometry. Variable-temperature solid-state dc magnetic susceptibility studies have been performed in the temperature range2-300K for complex10, and antiferromagnetic exchange interactions were found.