94890-19-4Relevant academic research and scientific papers
Chromium(III) and chromium(IV) tetraphenylporphine complexes
Zaitseva,Zdanovich,Golubchikov
, p. 843 - 847 (2008/10/08)
Stable chromium complex (AcO)CrTPP was synthesized through the reaction of meso-tetraphenylporphine with chromium(II) acetate in boiling phenol. Coordination properties of chromium porphyrin in reaction with imidazole and pyridine in o-xylene were studied by electronic absorption spectroscopy and computer modeling. A single-electron oxidation of chromium(III) complex was found to be affected by peroxide compounds. The stability of an extra complex depends on the basic properties of the extra ligand and oxidation number of the central metal atom. The complex stability correlates with the calculated energy of formation of the metal-extra ligand bond. The geometrical structure and energy parameters of hexacoordinated chromium porphyrins were calculated using the quantum-chemical method. The effect of the cis and trans position of ligands in the composition of a macrocyclic compound was established to be significant only in the extra complexes (AcO)CrTPP.
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.
Oxochromium compounds. 1. Synthesis and properties of μ-oxo chromium-iron porphyrin and phthalocyanine compounds
Liston, David J.,Kennedy, Brendan J.,Murray, Keith S.,West, Bruce O.
, p. 1561 - 1567 (2008/10/08)
The reaction between CrIVO(P) and FeII(P′) leads to the formation of μ-oxo heterobinuclear complexes (P)CrOFe(P′) where P and P′ represent dianions of porphyrins that may be the same or different. [Abbreviations for the dianions of 5,10,15,20-tetraarylporphyrins: TPP, tetraphenylporphyrin; TTP, tetra-p-tolylporphyrin; TMP, tetrakis(p-methoxyphenyl)porphyrin; TFP, tetrakis(p-fluorophenyl)porphyrin; TCP, tetrakis(p-chlorophenyl)porphyrin; TXP, tetra-3,5-xylylporphyrin; OEP, the dianion of 2,3,7,8,12,13,17,18-octaethylporphyrin; Pc, the dianion of the phthalocyanine molecule.] The complexes react with heterocyclic Lewis bases, and these coordinate to Cr only. The visible, infrared, 1H NMR, and Mo?ssbauer spectra are reported for the compounds. The variation of magnetic susceptibility with temperature down to 4.2 K is interpreted in terms of strong antiferromagnetic coupling between Cr(III) (S = 3/2) and Fe(III) (S = 5/2) centers with J values in the range -130 to -150 cm-1. Zero field splitting effects are important at low temperatures. The reaction of CrO(TPP) with FeII(Pc) forms an analogous μ-oxo complex having porphyrin and phthalocyanine groups attached to Cr(III) and Fe(III), respectively.
