155559-83-4Relevant academic research and scientific papers
Control of the Stereochemistry of Four-co-ordinate Copper(II) Complexes by Pyridinecarboxamide Ligands: Crystal Structure, Spectral and Redox Properties
Ray, Manabendra,Mukherjee, Rabindranath,Richardson, John F.,Mashuta, Mark S.,Buchanan, Robert M.
, p. 965 - 970 (2007/10/02)
Three copper(II) complexes 1>*H2O 1, 22> 2 and 32> 3 1 = N,N'-o-phenylenebis(pyridine-2-carboxamide); HL2 = N-phenylpyridine-2-carboxamide; HL3 = N-2,4,5-trichlorophenylpyridine-2-carboxamide> have beenn prepared and their stereochemical properties investigated.Complex 2 has been characterized by X-ray crystallography: space group P21/n, a = 10.853(4), b = 19.015(6), c = 10.293(3) Angstroem, β = 105.22(3) deg, Z = 4, R = 0.030, R' = 0.034 for 2938 observed reflections.Compared to the known square-pyramidal structure of 1 it is revealed that the deprotonated bidentate ligand L2 exerts a measureable degree of geometric control over the co-ordination sphere of 2 (distorted towards tetrahedral).Similar effects are also observed from absorption and EPR spectral results.The Cu(II)-Cu(I) redox potentials in dimethylformamide solution have been determined by cyclic voltammetry.Upon replacement of the tetradentate L1 ligand by two uninegative bidentate L2 or L3 ligands, of similar donor set, a marked positive shift (ca. 0.6-0.7 V) was observed, implying the predominance of structural effects.
