Electron-gain and -loss centres in irradiated di-imidazolesilver(I) nitrate

Abstract

Exposure of powder and single-crystal samples of di-imidazolesilver(I) nitrate to ⁶⁰Co γ-rays at 77 K gives paramagnetic centres whose e.s.r. spectra are characteristic of NO₂ radicals formed by electron gain and silver(II) centres formed by electron loss. There is no evidence for electron capture at silver(II), nor for any significant damage to the imidazole ligands. The e.s.r. spectra for the silver(II) centre show hyperfine coupling to ¹⁰⁹Ag and ¹⁰⁷Ag, and also to two equivalent ¹⁴N nuclei. The results suggest a major silver contribution from the 4d_x²–y² orbital, where x is the N–Ag–N direction. This establishes the presence of co-ordinated nitrate ligands in addition to the two imidazole ligands.