Copper(II) coordination chemistry of potentially octadentate (N8) tetrapyridyl and tetrapyrazolyl-pyridazine ligands. X-ray crystal structures of [Cu2(PTAPY)Br4]·2DMF and [Cu2(PTAPY)(NO3)2(N3)(H2O)]2(NO3)2·1.2CH3OH
| Autor: | Sean Connors, Laurence K. Thompson, S. S. Tandon, Liqin Chen, John N. Bridson |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
chemistry.chemical_classification
Ligand Stereochemistry chemistry.chemical_element Crystal structure Triclinic crystal system Copper Coordination complex Inorganic Chemistry Pyridazine chemistry.chemical_compound Crystallography chemistry X-ray crystallography Materials Chemistry Azide Physical and Theoretical Chemistry |
| Zdroj: | Inorganica Chimica Acta. 213:289-300 |
| ISSN: | 0020-1693 |
| DOI: | 10.1016/s0020-1693(00)83839-6 |
| Popis: | The structural, electrochemical, ESR and magnetic properties of a series of dinuclear copper(II) complexes of two new polyfunctional pyridazine ligands, 3,6-bis( N,N,N′,N′ -tetrakis(pyridine-2-ylmethyl)-aminoethanethiolato pyridazine (PTAPY), and 3,6-bis( N,N,N′,N′ -tetrakis(pyrazol-1-ylmethyl)-aminoethanethiolato pyridazine (PTAPZ) are discussed. PTAPY and PTAPZ are potentially octadentate (N 8 ) ligands and on reaction with copper(II) salts form dinuclear complexes, [Cu 2 (PTAPY)X 4 ]·yH 2 O (X=NO 3 , y=1 ( I ); X=Br, y=2 ( II )), [Cu 2 (PTAPY)(CH 3 CN) 2 ](ClO 4 ) 4 ·0.5C 2 H 5 OH ( III ), [Cu 2 (PTAPZ)Cl 4 ]·5H 2 O ( V ), and a tetranuclear complex [Cu 2 (PTAPY)(NO 3 ) 2 (N 3 )(H 2 O)] 2 (NO 3 ) 2 ·1.2CH 3 OH ( IV ). The single crystal X-ray structures of compounds II and IV have been determined, and in each case the ligand is hexadentate. II ([Cu 2 (PTAPY)Br 4 ]·2DMF) crystallized in the triclinic system, space group P 1 , with a =14.037(3), b =14.941(4), c =11.782(6) A, α=103.77(3), β=106.08(3), γ=84.59(2)°, V =2305(2) A 3 and Z =2 ( R =0.036 and R w =0.032). Two different five-coordinate (CuN 3 Br 2 ) geometries exist within the same molecule. IV crystallized in the triclinic system, space group P 1 , with a =14.876(5), b =16.172(4), c =10.068(2) A, α=95.45(2), β=108.40(2), γ=64.74(2)° and Z =2 ( R =0.058 and R w =0.051). The two copper atoms are quite different with six- (axially elongated, distorted tetragonal) and five- (distorted square- pyramidal) coordinate arrangements, and dimerization through azido nitrogens results in the formation of a tetranuclear azide bridged molecule. The pyridazine nitrogens remain uncoordinated in all complexes and there is no magnetic interaction between the distant copper centers. Cyclic voltammograms are characterized by the presence of either one ‘two-electron’ or two ‘one-electron’ (overlapping) reversible or quasi-reversible redox processes, associated with the reduction of the dinuclear copper(II) species to dinuclear copper(I) species. |
| Databáze: | OpenAIRE |
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