Nitric oxide (NO) reactivity studies on mononuclear iron(II) complexes supported by a tetradentate Schiff base ligand

作者：Tyagi Nidhi; Singh Ovender; Singh Udai P; Ghosh Kaushik

来源：RSC Advances, 2016, 6(116): 115326-115333.

DOI：10.1039/c6ra21659e

Mononuclear high-spin [Fe-II(Gimpy)(Cl)(2)], (1) and low-spin [FeII(Gimpy)(CN)(2)]center dot 3H(2)O, (2 center dot 3H(2)O) complexes, where; Gimpy: (1,2-bis(2-phenyl-2-(pyridin-2-yl) hydrazono) ethane), were synthesized and characterized by various analytical and spectral techniques. The NO reactivity of complex 2 center dot 3H(2)O via acidified nitrite solution gave rise to a mixture of two different complexes; a ligand nitrated unsymmetrical complex [Fe(Gimpy-NO2)(CN)(2)]center dot CH2Cl2, (3 center dot CH2Cl2) via electrophilic route as well as nitrosylation at the metal centre, formation of unstable complex [Fe(Gimpy)(NO)(CN)](2+), (4). Formation of unstable complex 4 was monitored via visual colour change from purple to brownish-red and evidence of this complex has been established by means of in situ IR, ESI-MS and UV-visible spectral studies. In addition, the structures of complexes 2 center dot 3H(2)O and 3 center dot CH2Cl2 have been established unambiguously through single crystal X-ray diffraction analysis. Interestingly, after nitration of imine proton twisting of one phenyl ring (near to -NO2 group) in complex 3 was obtained, leading to an unsymmetrical complex 3 (nitration of one imine proton only is supported by theoretical studies), possibly due to steric hindrance of -NO2 group and results of electrochemical studies of all complexes (1-3) were also examined.

• 出版日期2016