Nitrosoalkane complexes of iron-porphyrins: analogy between the bonding properties of nitrosoalkanes and dioxygen

Formation of Iron(II)–Nitrosoalkane Complexes: A New Activity of Microperoxidase 8

“…Third, when complex 7 was analyzed by 1 H NMR spectroscopy in CD 3 OD, a spectrum characteristic of a diamagnetic species was obtained (data not shown) and two signals corresponding to the protons of the iPrN ϭ O ligand of the iron atom were observed at Ϫ0.80 ppm (m, 1H, C-H) and Ϫ2.05 ppm (d, 6H, -CH 3 ). Those signals were identical to those already reported for the protons of the iPrN ϭ O ligand of the iron atom in diamagnetic iron(II) (iPrNO) (tetraarylporphyrin) complexes (18).…”

“…This MP8-Fe(II)-N(O)R structure was completely confirmed for the iPrNHOH-derived complex by the following: (i) the direct formation of complex 7 by coordination of 2-nitrosopropane on the iron(II) of MP8 previously reduced by sodium dithionite (Fig. 3), (ii) the 1 H NMR spectrum of complex 7 which is characteristic of an iron(II) diamagnetic species with signals due to the protons of the nitroso-2-propane ligand almost identical to those already reported for the diamagnetic iron(II) (iPrNO) (tetraarylporphyrin) complexes (18).…”

Synthesis and molecular structures of N,N-dialkyl-4-nitrosoaniline adducts of formally d6 metalloporphyrins of ruthenium and cobalt

“…The reaction of Co(TPP)Cl with AgSbF 6 in THF resulted in the formation of [Co(TPP)(THF) 2 ]SbF 6 (equation (2) 4 suitable for single-crystal X-ray diffraction studies were grown. The crystal structure of this compound (Fig.…”

“…Indeed, structural information on the binding of C-nitroso compounds to heme centers has so far been mostly obtained as a result of work with synthetic metalloporphyrins. For example, Mansuy and coworkers showed that the nitrosoalkane in Fe(TPP) (i-PrNO)(i-PrNH 2 ) (TPP 2À = 5,10,15,20-tetraphenylporphyrinato dianion) binds to the metal center via its N-atom [4]. Mononitrosoarene complexes of the form Fe(TPP)(Ar-NO)L (Ar = Ph, ONC 6 H 4 NMe 2 ; L = pyridine, 1-methylimidazole) have also recently been structurally characterized and reveal N-binding of the nitrosoarene ligands [5].…”

Simple Heme Dimers with Strongly Cooperative Ligand Binding

“…The isocyanide and nitrosoaryls were chosen as analogues of CO and O 2 , respectively. [10] Spectrophotometric titrations proceeded with well-defined isosbestic points, [8] a result indicative of interconversion between only two chromophores: the five-coordinate and six-coordinate hemes. The binding constants and allosteric interaction energies are independent of the solvent and the dimer concentration, a fact that rules out competition between dimerization and ligand binding as the origin of the cooperativity.…”