Synthesis of the 17-electron cations [FeL(L′)(NO)₂]⁺(L, L′= PPh₃, OPPh₃): structure and bonding in four-co-ordinate metal dinitrosyls, and implications for the identity of paramagnetic iron dinitrosyl complex catalysts

The Preparation, Structural Characteristics, and Physical Chemical Properties of Metal-Nitrosyl Complexes

“…In turn, the nitrosyl stretching frequencies observed for both 11 and 12 appear at even lower wavenumbers. The macrocyclic DPPM-supported complex, 11 , exhibits four distinct IR absorptions (1733, 1721, 1687, and 1668 cm −1 ) in the solid state and in solution, possibly arising from the interaction of the Fe(NO) 2 centers, as has been observed in other cyclic systems [37, 38]. This phenomenon appears to depend on ring size, as the related ten-membered ring compound, 12 , displays only two nitrosyl stretching signals (1723 and 1679 cm −1 ) in both the solid and liquid states.…”

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

“…In the reported mononuclear DNICs, both the {Fe(NO) 2 } 9 and {Fe(NO) 2 } 10 oxidation states are commonly encountered [20][21][22][23][24][25][26][27][28][29][30][31]. Regarding the electronic structure of the {Fe(NO) 2 } core in DNICs, the reported stable mononuclear DNICs can be classified into two groups: paramagnetic {Fe(NO) 2 } 9 core (S t = 1/2) and diamagnetic {Fe(NO) 2 } 10 core (S t = 0).…”

“…Regarding the electronic structure of the {Fe(NO) 2 } core in DNICs, the reported stable mononuclear DNICs can be classified into two groups: paramagnetic {Fe(NO) 2 } 9 core (S t = 1/2) and diamagnetic {Fe(NO) 2 } 10 core (S t = 0). From other experimental and calculation studies, both states have also been identified by their stretching frequencies (ν(N-O) (>1700 cm −1 in {Fe(NO) 2 } 9 versus <1700 cm −1 in {Fe(NO) 2 } 10 ) as well as ν(Fe-NO) (~550 cm −1 in {Fe(NO) 2 } 9 versus~600 cm −1 in {Fe(NO) 2 } 10 ) as listed in Table 1 [20][21][22][23][24][25][26][27][28][29][30][31]. The well-characterized {Fe(NO) 2 } 9/10 cores are [Fe(NO) 2 (dmp)] 0/− where dmp = 2,9-dimethyl-1,10-phenanthroline [20] and Table 1.…”

A theoretical study on single-electron reduction of a thiolate-bridged diiron diazene complex

“…As the result of reduction of 1 + to 2, the lengths of both Fe-N bonds in 2 are 1.882 Å and are apparently longer in comparison with that in 1 + (1.844 Å and 1.824 Å for the two Fe−N bonds, respectively), while N-N bond is slightly shortened upon the reduction (1.317 Å in 1 + vs. 1.316 Å in 2). This process is best viewed as a metal-based reduction because the Fe-d orbital can act as the electron acceptor[39,40]. This is understandable in view of the SOMO of 1 + , featuring N−N π-bonding and Fe−N π*-bonding (Figure 2a).…”