Influence of ligand backbones and counter ions on stuctures of helical silver(I) complexes with di-Schiff bases derived from phthalaldehydes and diamine

摘要

Five silver(I) complexes of Schiff bases, [Ag_2L_2][ClO_4]_2 1, [Ag_2L_2][PF_6]_2·H_2O 2, [Ag_2L_2][NO_3]_2 3, _(propor. to)~1[(AgL')(dnb)(H_2O)_(0.25)] (dnb = 3, 5-dinitrobenzoate) 4 and _(propor. to)~1[(AgL')(NO_3)] 5 were synthesized, where L and L' are derived from the [1 + 2] condensation of 2-9aminoethylamino)ethanol with isophthalaldehyde or terephthalaldehyde. Complexes 1, 2, 4 and 5 have been structurally characterised by X-ray crystallography, which shows that the cations in 1 and 2 have similar double helical structures, and 4 has a single-stranded helical structure. However, complex 5 exhibits a one-dimensional staircase-like structure. Each Ag atom in 1, 2 and 4 adopts a highly distorted tetrahedral geometry, while that in 5 features a T-shaped geometry. In solution, 1-3 have virtually identical ~1H NMR spectra, similar FAB mass spectra and electrochemical properties.