Mononitrosyl Iron Complexes Supported by Sterically Hindered Carboxylate Ligands

Abstract

Complexes that feature a single NO bound to Fe, as postulated in various carboxylate-rich metalloproteins, were prepared by mixing Fe(II) salts, NO, and the sterically encumbered 2,6-dimesitylbenzoate (Mes2ArCO2-). Among the compounds isolated are the potentially useful heterobimetallic synthon Tl(mu-Mes2ArCO2)3Fe(NO) and a novel cubane Fe4(Mes2ArCO2)4(NO)4(mu3-OH)4 that forms in the presence of added H2O and features syn-[FeNO]2 units.

Synthesis, Structures, and Magnetic Properties of Three 3D Coordination Polymers Based on M4O4 Cubanes (M = MnII, FeII, CoII)

“…In each cubane structure of 1 – 3 , there exist four μ 3 ‐O bridges and four syn – syn bridging carboxylato ligands (Scheme e). Such a bridging mode of ligands is also observed for cubanes of Co II 4 O 4 ,14d Co III 4 O 4 ,14g Fe II 4 O 4 ,14i and Fe II 3 Fe III O 4 14j but has not been found for Mn II 4 O 4 cubane. Thus, complex 1 is the first example of an Mn II 4 O 4 cubane that has four μ 3 ‐O bridges and four syn – syn bridging carboxylato ligands.…”

Understanding the Unusually Straight: A Search For MO Insights into Linear {FeNO}7 Units

“…10,11 Key examples of structurally characterized, S ) 3/2 species with linear FeNO groups include anionic, pseudotetrahedral tristhiolato- 12,13 and triscarboxylato-{FeNO} 7 complexes. 14 To this list must be added the well-known S ) 0 Roussin's black salt anion, [Fe 4 (µ-S) 3 (NO) 7 ] -, [15][16][17][18][19] whose unique linear FeNO unit is believed to be (locally) an S ) 3/2, {FeNO} 7 center. Now, although some of these systems have been studied by quantum chemical methods, 9,11,18 no comprehensive theoretical study has been reported so far, which provided the key motivation for this study.…”

“…Against this broad context, a handful of nonheme {FeNO} 7 complexes, both S = 1/2 and 3/2, stand out, which are characterized by essentially linear {FeNO} 7 groups. Thus, the two S = 1/2 complexes [Fe(CN) 4 (NO)] 2− and Fe(dtc-Me 2 ) 2 (NO) (dtc-Me 2 = N , N ′ -dimethyldithiocarbamate) feature strictly linear FeNO units. , Key examples of structurally characterized, S = 3/2 species with linear FeNO groups include anionic, pseudotetrahedral tristhiolato- , and triscarboxylato-{FeNO} 7 complexes . To this list must be added the well-known S = 0 Roussin’s black salt anion, [Fe 4 (μ-S) 3 (NO) 7 ] − , − whose unique linear FeNO unit is believed to be (locally) an S = 3/2, {FeNO} 7 center.…”

Self-Assembly of the 2-His-1-carboxylate Facial Triad in Mononuclear Iron(II) and Zinc(II) Models of Metalloenzyme Active Sites

“…Initial synthetic efforts focused on the treatment of CH 2 Cl 2 solutions of [(Me 4 eda)MCl 2 ] n (Me 4 eda = N , N , N ‘, N ‘-tetramethylethylenediamine; M = Fe, n = 2; M = Zn, n = 1) with either 1 or 2 equiv (per metal) of MesCO 2 X (X = Li or Tl; Scheme ). Chloride metathesis was facile for M = Fe and X = Li, but thallium carboxylate was required for M = Zn.…”