84174-79-8Relevant academic research and scientific papers
Stereoelectronic Aspects of Inter-Metal Nitrogen Atom Transfer Reactions between Nitridomanganese(V) and Chromium(III) Porphyrins
Bottomley, Lawrence A.,Neely, Frank L.
, p. 5435 - 5439 (2008/10/09)
Reactions of nitridomanganese(V) porphyrins with chromium(III) porphyrins resulted in the irreversible formation of nitridochromium(V) porphyrins and manganese(III) porphyrins. The progress of these reactions has been followed spectrophotometrically, electrochemically, and spectroscopically by EPR. Kinetic analysis of the spectrophotometric data obtained during these reactions for a variety of substituted porphyrins showed the reactions to be first order in each of the reactants. Rate constants were dependent upon the electronic and steric effects of the porphyrin substituent, upon the identity of the anion bound to the chromium(III) reactant, and upon the solvent dielectric constant. We propose that the mechanism of these nitrogen atom transfer reactions involves the nucleophilic attack of the nitridomanganese porphyrin donor on the cationic chromium(III) porphyrin acceptor facilitating a net, two-electron redox process mediated by a heterobimetallic μ-nitrido intermediate. This report represents the first systematic study of the stereoelectronic effects involved in the complete, inter-metal nitrogen atom transfer between two metalloporphyrins.
Inter-Metal Nitrogen Atom Transfer Reactions between Nitridochromium(V) and Chromium (III) Porphyrins
Neely, Frank L.,Bottomley, Lawrence A.
, p. 5432 - 5434 (2008/10/09)
Reactions of nitridochromium(V) porphyrins with chromium(III) porphyrins resulted in reversible, inter-metal nitrogen atom transfer between the two chromium porphyrin complexes. The progress of these reactions was followed spectrophotometrically. Kinetic analysis of the spectral data obtained over time for a variety of substituted porphyrins showed the reactions to be first order in each of the reactants and second order overall. Equilibrium constants were computed from the spectral data and ranged from 0.56 to 2.1 for the reactions between nitridochromium(V) octaethylporphyrin and a series of chlorochromium(III) tetraphenylporphyrins possessing phenyl ring substituents. Forward rate constants were determined for this reaction series and ranged from 6.8 to 1420 M-11 s-1. Electron-withdrawing substituents enhanced the forward rates but diminished the equilibrium constants. It is proposed that the reactions proceed by nucleophilic attack of the nitridochromium porphyrin donor on the cationic chromium(III) porphyrin nitrogen atom acceptor facilitating a net, two-electron redox process mediated by a homobimetallic μ-nitrido intermediate.
Pyrolysis of Azidomanganese(III) Porphyrin Affording Nitridomanganese(V) Porphyrin
Yamamoto, Yuichi,Imamura, Taira,Suzuki, Toru,Fujimoto, Masatoshi
, p. 261 - 262 (2007/10/02)
Azidomanganese(III) meso-tetraphenylporphyrin, MnIII(tpp)N3, in the solid state was pyrolyzed around 236 deg C to yield nitridomanganese(V) meso-tetraphenylporphyrin, MnV(tpp)N.
Photoirradiated and γ-ray-irradiated reactions of manganese(III, IV, V) tetraphenylporphyrins in 2-methyltetrahydrofuran. Reactions of azidomanganese(III) porphyrin
Jin, Takashi,Suzuki, Toru,Imamura, Taira,Fujimoto, Masatoshi
, p. 1280 - 1285 (2008/10/08)
Manganese(III, IV) tetraphenylporphyrins MnIII(TPP)X (TPP = 5,10,15,20-tetraphenylporphinato; X = I, Br, Cl, N3, NCS, OAc) and MnIV(TPP)(OCH3)2 in 2-methyltetrahydrofuran (MeTHF) at room temperature were reduced to yield MnII(TPP) by photoirradiation with visible light (440-750 nm) or by γ-ray irradiation. The photoirradiation of MnIII(TPP)N3 in the rigid matrix at 77 K affords MnV(TPP)N. Photochemically stable MnV(TPP)N was reduced to MnII(TPP) by γ-irradiation at room temperature. γ-Irradiation of MeTHF solutions of MnIII(TPP)X at 77 K causes one-electron reduction to form the constrained complexes [MnII(TPP)X]-. Warming the matrices after γ-irradiation formed MnII(TPP), liberating ligand X-. The near-infrared bands of MnIII(TPP)X red shift along with the shifts of the bands in the visible region by varying the ligand X. The characteristic bands of the constrained complex [MnII(TPP)X]- in the near-infrared region red shift in the order X = Cl > Br > I. The photoirradiation of CrIII(TPP)N3 with visible light affords CrV(TPP)N at room temperature and at 77 K.
Synthesis and molecular structure of a nitrido(porphyrinato)chromiuin(V) complex
Groves, John T.,Takahashi, Tadashi,Butler, William M.
, p. 884 - 887 (2008/10/08)
Irradiation of solutions of azido(5,10,15,20-tetra-p-tolylporphyrinato)chromium(III) in methylene chloride or benzene gave nitrido(5,10,15,20-tetra-p-tolylporphyrinato)chromium(V) (1) in yields of 59% and 82%, respectively. Solutions of 1 showed well-resolved EPR spectra at room temperature (g = 1.985, A53Cr = 2.85 mT, AN = 0.279 mT). The IR spectra of nitrido(5,10,15,20-tetra-p-tolylporphyrinato)chromium(V) (1) and 1-15N showed bands at 1017 and 991 cm-1, which were assigned to vCr≡14N and vCr≡15N, respectively. The molecular structure of 1·C6H6 indicated a chromium-nitrogen distance of 1.565 A?, with the chromium 0.42 A? above the mean plane of the pyrrole nitrogens. The periphery of the porphyrin ring was saddle-shaped with excursions 0.56 A? below and 0.29 A? above the plane of the pyrrole nitrogens.
