84151-95-1Relevant 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 (1997)
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.
Oxochromium compounds. 2. Reaction of oxygen with chromium(II) and chromium(III) porphyrins and synthesis of a μ-oxo chromium porphyrin derivative
Liston, David J.,West, Bruce O.
, p. 1568 - 1576 (2008/10/08)
The reaction of oxygen with Cr(II) porphyrin complexes in solution has been found to result in the formation of CrIVO(P) compounds when oxygen is in excess. Solid CrII(P) also react irreversibly with oxygen, and the products dissolve in toluene to form CrIVO(P). The complex (TPP)CrOCr(TPP) has been isolated from the reaction of CrO(TPP) and CrII(TPP) and shown to undergo further reaction with oxygen to give CrO(TPP). The complex shows an IR absorption at 860 cm-1, considered to indicate the presence of the CrOCr linkage, and has μeff = 1.61 μB per Cr at 300 K, indicating substantial antiferromagnetic coupling. Similar μ-oxo complex formation has been demonstrated spectroscopically between other CrO(P)/Cr(P′) combinations where P and P′ may be the same or different. (P)CrOCr(P) complexes can be detected as intermediates in the reaction of CrII(P) with oxygen when the amount of oxygen is restricted. CrIII(P)Cl also reacts with oxygen in chloroform in the presence of HCl to give intermediates that are converted to CrIVO(P) in the presence of basic alumina. A Cr-porphyrin π-cation radical is proposed as the intermediate.
