Abstract:
In biological systems, different types of nitrite reductase (NiRs) and nitric oxide synthase (NOS) isozymes are present to generate NO for physiological activities. To mimic this function, we choose the acid-induced path to reduced nitrite for nickel-nitrite metal complexes. In this study, we utilized the (BimH)3 ligand framework and synthesized three different complexes, namely [(BimH)3NiII(μ-Cl)2NiII(BimH)3]Cl2 (1), [(BimH)3NiII(L1)(L2)][NO3]2 (2), and [(BimH)3NiII(κ2O2NO)](NO3) (3). These complexes are characterized by different methods such as 1H, ESI-MS, SCXRD, UV-Vis, FT-IR. 2 and 3 are used to synthesis a main precursor [(BimH)3NiII(κ2-ONO)][NO3] (4) complex. Acid induced reduction of 4 leads to detachment of nitrite from the nickel sites as evident from the disappearance of the nitrite band in the FTIR. ESI-MS spectra reveals the formation of 2,5-di-tert-butylcatechol which is an indirect evidence of the homolytic N-O bond cleavage upon protonation.
