Structures and Properties of Dinitrosyl Iron and Cobalt Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane

Abstract

Two dinitrosyl iron and cobalt complexes [Fe(NO)2(L1”)](BF4) and [Co(NO)2(L1”)](BF4) are synthesized and characterized, supported by a less hindered bidentate nitrogen ligand bis(3,5-diisopropyl-1-pyrazolyl)methane (denoted as L1”), are surprisingly stable under argon atmosphere. X-ray structural analysis shows a distorted tetrahedral geometry. Spectroscopic and structural parameters of the dinitrosyl iron and cobalt complexes are consistent with the previous reported {Fe(NO)2}9 and {Co(NO)2}10. Two N–O and M–N(O) stretching frequencies and their magnetic properties are also consistent with the above electronic structural assignments. We explored the dioxygen reactivities of the obtained dinitrosyl complexes. Moreover, the related [FeCl2(L1”)], [Co(NO3)2(L1”)], and [Co(NO2)2(L1”)] complexes are also characterized in detail.

Coordinatively Unsaturated Nickel Nitroxyl Complex: Structure, Physicochemical Properties, and Reactivity toward Dioxygen

“…The ν(N- 16 O/ 18 O) shift is in agreement with half of the value (19 cm −1 = 1201-1182) of the shift (32 cm −1 ) calculated using the reduced mass, assuming two 18 O are incorporated in the NO 2 − group. This is consistent with the solution state reactivity, which shows one oxygen atom from O 2 being incorporated into the NO 2 − group [20,21,36,40]. The exact assignment of the 1201 cm −1 feature is further discussed in the computational section below.…”

“…However, we thought that simple nickel-NO complexes such as [Ni(NO)(I)] n could also be used for the synthesis [35]. In fact, [Fe(NO) 2 (I)] 2 and [Co(NO) 2 (I)] n were used to synthesize M-NO complexes such as [Fe(NO)(L3)] [20], [Fe(NO) 2 (L1 )](BF 4 ), and [Co(NO) 2 (L1 )](BF 4 ) [36] previously. Moreover, we succeeded in the synthesis of [Ni(NO)(L0f)] by using both [Ni(NO)(Br)(PPh 3 ) 2 ] and [Ni(NO)(I)] n [27].…”

Investigating the Structural, Electronic, and Topological Properties of [BMIm][Fe(NO)2Cl2] Magnetic Ionic Liquid: Density Functional Theory Approaches

“…Here, n is the sum of the metal-d electrons and NO-π* orbitals, and x is the number of NO ligands. 33 A theoretical study by methods of quantum mechanics is obligatory to gain a more accurate insight into the structure and electronic properties as well as to predict the behavior of this MIL, which is essential for the different chemical processes. Among different molecular theories, DFT is a modified contribution by various approaches for improving computation precision.…”

“…Among the paramagnetic ILs, an analogous MIL is [BMIm]­[Fe­(NO) 2 Cl 2 ] which has been synthesized by Gual and co-workers in 2018 for the first time, possessing unique potential for various applications as a magnetic material . Nitric oxide (NO) plays a pivotal role as a messenger radical in various physiological processes such as regulating the vascular tone, neuromodulation, myocardial metabolism, and nerve signal transduction, , to name a few. The NO molecule was named the molecule of the year in 1992 because of its vital importance in biological systems as a chemical messenger. , Due to the very short lifetime of NO in vivo, NO is established in two forms: dinitrosyl iron complexes (DNICs) and S-nitrosothiols (RSNO).…”

“…Moreover, the bond between transition metals and nitric oxide is not necessarily unique, thus the distribution of electrons cannot be determined without theoretical or spectroscopic studies. Here, n is the sum of the metal-d electrons and NO-π* orbitals, and x is the number of NO ligands …”