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Syntheses, Structures And Characterizations Of Polynuclear Copper(II) Complexes

Posted on:2009-10-23Degree:MasterType:Thesis
Country:ChinaCandidate:D Y ChengFull Text:PDF
GTID:2131360302462990Subject:Inorganic Chemistry
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Polynuclear copper(II) complexes are of continuous interest due to their potential applications in molecule-based magnets, novel catalytic materials as well as in modeling multimetallic active sites of metalloenzymes. This thesis reviewed more than 170 papers about polynuclear copper complexes according to the nuclearity. The Hamiltonian and the van Vleck magnetic equations of those polynuclear copper clusters have been summarized. The applications of polynuclear copper complexes in electrochemistry, catalysis and biological activities and the synthetic strategies of multinuclear copper(II) clusters have also been reviewed. Then 13 copper(II) complexes based on different polynuclear copper(II) skeletons afforded from self-assembly strategies, {[Cu4(bpy)4(OH)4(H2O)2]}(NO3)2(C5H6O4)·8H2O (1),{[Cu4(bpy)4(OH)4(H2O)2]}-(C5H6O4)2·16H2O (2),{[Cu4(bpy)4(OH)4(H2O)2]}(C8H4O4)2·6H2O (3),{[Cu4(bpy)4(OH)4(H2O)2]}(NO3)2(C7H5O2)2·6H2O (4),{[Cu6(bpy)6(OH)6(H2O)2]}-(C6H8O4)3·23H2O (5),{[Cu6(bpy)6(OH)4(NO3)2]}(NO3)4·5H2O (6),{[Cu(phen)2]2(C6H8O4)}-(ClO4)2 (7),{[Cu(phen)2]2(C6H8O4)}(ClO4)2·1.33H2O (8),{[Cu2(phen)2(H2O)]2(C6H8O4)2}-(ClO4)4 (9),{[Cu2(bpy)2- (H2O)]2(C6H8O4)2}(ClO4)4·2H2O (10),[Cu4(H2O)2(phen)4(μ4-PO4)2(μ2-O)]·11H2O (11),[Cu4(bpy)4(μ4-PO4)2(μ2-Cl)2]·10H2O (12),[Cu2(bpp)4(H2PO4)2]-(HPO4)·H2O (13) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, bpp = 1,3-bis(4-pyridyl)propane, C5H6O4 = glutarate anion, C8H4O4 = terephthalate anion, C7H5O2 = benzoate anion,C6H8O4 = adipate anion) were presented and their X-ray single crystal diffraction, X-ray powder diffraction, IR spectra, TG-DTA analyses, magnetic analyses and electrochemistry were also demonstrated.The self-assembly of Cu2+, 2,2'-bipyridine and carboxylate/dicarboxylate ligands in alkaline solutions afforded a series of hydroxo-bridged tetra- and hexanuclear copper complexes. The complex cations of 1-4 and complex 5 exhibit stepped-like tetranuclear copper(II) clusters [Cu4(bpy)4(μ2-OH)2(μ3-OH)2(H2O)2]4+ and hexanuclear cluster [Cu6(bpy)6(μ2-OH)2(μ3-OH)4(H2O)2]6+, respectively. Each Cu(II) ion is located in a pentacoordinated square pyramidal environment and the apical position of the Cu(II) ion in the out side is occupied by an aqua O atom. Complex 6 displays a hexanuclear cluster [Cu6(bpy)6(μ2- OH)2(μ3-OH)4(NO3)2]4+, in which theμ2-bridging NO3– coordinate to the two out side Cu(II) ions to make them locate in pentacoordinated square pyramidal and hexacoordinated octahedral environments, respectively. Intra- and intercationicπ-πstacking interactions between bipyridine ligands in 1-6 contribute to the stabilization of the polynuclear copper clusters and the formation of 2D supramolecular layers with channel structures. The lattice water molecules are hydrogen bonded to the counter-anions and interpenetrated with the supramolecular cationic layers to afford 3D hydrogen bonded networks. Magnetic analyses indicated ferromagnetic coupling interactions within the tetranuclear clusters while dominant antiferromagnetic interactions for the hexanuclear skeleton.Complexes of 7–10 were obtained from reactions of Cu(ClO4)2·6H2O, adipic acid and 2,2-bpy or 1,10-phenantroline by adjusting the pH of the solution as well as the molar ratio of the materials. Complexes 7 and 8 are characteristic of adipato-bridged dumbbell-like dinuclear copper(II) cations, which forms 2-fold interpenetrating (4,4) net like supramolecular structures with the perchlorate anions and lattice water molecules filling in the cavities. Complexes 9 and 10 contains the double–semi–paddle–wheel (DSPW) tetranuclear {[Cu2(phen)2(H2O)]2(COO)4} and {[Cu2(bpy)2(H2O)]2(COO)4} clusters, which could be demonstrated as the dimmer of semi-paddle-wheel dinuclear clusters. The 4-connected tetranuclear clusters are interlinked each other to form (4,4) covalent networks with perchlorate anions and lattice water molecules locating in the channels. magnetic analyses indicated that the copper ions within the SPW-like dinuclear units shows antiferromagnetic coupling interactions while the copper ions in the middle Cu2O2 rings display weak ferromagnetic interactions. Between -1.2–0.8 V, complexes 9 and 10 display two quasi-reversible redox couples, indicating the copper ions are redoxed as CuIICuII ? CuIICuI ? CuICuI.The reactions of CuCl2·2H2O, phosphoric acid and 1,10-phenathroline/2,2'-bpy result in the formation of complexes 11 and 12. They contains phosphate-bridged tetranuclear copper(II) complex molecules [Cu4(H2O)2(phen)4(μ4-PO4)2(μ2-O)] and [Cu4(bpy)4(μ4-PO4)2(μ2-Cl)2], respectively. They lattice water molecules are filling between the supramolecular layers formed by the complex molecules throughπ-πstacking interactions. The reaction of Cu(OH)2, bpp and phosphoric acid afforded complex 13, in which the Cu(II) atoms are bridged by the bpp ligands to form 2D layers parallel to (011) and (101). The layers are interpenetrating to form inclined (4,4) topology with channel structrues. The H2PO4– and HPO4– anions are hydrogen bonded to the lattice water molecules and reside in the channels.
Keywords/Search Tags:polynuclear copper(II) clusters, hydroxo-bridged, dicarboxylic acid, phosphoric acid, crystal structures
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