77944-60-6Relevant academic research and scientific papers
Use of chemical kinetics for the description of metal porphyrin reactivity
Lomova, Tatyana N.,Klyueva, Mariya E.,Tyulyaeva, Elena Yu.,Bichan, Nataliya G.
, p. 1040 - 1054 (2013/01/15)
The results of use of chemical kinetics receptions, approaches and methods for the study of porphyrins and their metal complexes reactivity are discussed on an example of oxidation, acid-basic, and catalytic reactions of rhodium, palladium, and rhenium complexes of porphyrin in liquid solutions. The peculiarity of the porphyrin reaction rates is analyzed in a brief context of general provisions of the chemical kinetics. The opportunity to use the quasistationarity principle at the definition of the kinetic equation of the reactions with participation of metal porphyrins is shown. The transition from the process kinetic description to consideration of its mechanism is explored.
Comparison of molecular conductance between planar and twisted 4-phenylpyridines by means of two-dimensional phase separation of tetraphenylporphyrin templates at a liquid-HOPG interface
Sakano, Takeshi,Higashiguchi, Kenji,Matsuda, Kenji
supporting information; experimental part, p. 8427 - 8429 (2011/09/16)
Tetraphenylporphyrin (TPP) rhodium chlorides coordinated by planar and twisted 4-phenylpyridine derivatives were synthesized. An STM image was taken by a 2-D phase separation technique and the conductance was evaluated. Difference in apparent height betwe
Effects of p-substituents on electrochemical CO oxidation by Rh porphyrin-based catalysts
Yamazaki, Shin-Ichi,Yamada, Yusuke,Takeda, Sahori,Goto, Midori,Ioroi, Tsutomu,Siroma, Zyun,Yasuda, Kazuaki
experimental part, p. 8968 - 8976 (2011/04/25)
Electrochemical CO oxidation by several carbon-supported rhodium tetraphenylporphyrins with systematically varied meso-substituents was investigated. A quantitative analysis revealed that the p-substituents on the meso-phenyl groups significantly affected CO oxidation activity. The electrocatalytic reaction was characterized in detail based on the spectroscopic and X-ray structural results as well as electrochemical analyses. The difference in the activity among Rh pophyrins is discussed in terms of the properties of p-substituents along with a proposed reaction mechanism. Rhodium tetrakis(4-carboxyphenyl)porphyrin (Rh(TCPP)), which exhibited the highest activity among the porphyrins tested, oxidized CO at a high rate at much lower potentials (2 oxidation activity, in contrast to Pt-based catalysts.
Electronic and steric effects on the stereoselectivity of cyclopropanation reactions catalysed by rhodium meso-tetraphenylporphyrins
Tagliatesta, Pietro,Pastorini, Alessandra
, p. 127 - 133 (2008/10/08)
The rhodium meso-tetraphenylporphyrins catalysed cyclopropanation reactions of styrene, cyclohexene and norbornene by ethyldiazoacetate (EDA), have been investigated. The electronic effects of the bromine groups in the β-positions of the porphyrins can be correlated to the syn/anti ratio obtained for the reaction products in the case of styrene, showing a good linear correlation between the sum of the Hammett's σp and the logarithm of the obtained selectivity. A decrease in the stereochemical ratio on increasing the number of halogen atoms was observed. This is not the case for cyclohexene and norbornene which show a different behavior and do not give good linear correlation. Furthermore, when the rhodium porphyrins have bulky methoxy substituents in the ortho-positions of the phenyl rings, comparing with the simple rhodium meso-tetraphenylporphyrin, the isomeric ratios decrease dramatically for styrene whilst for the other substrates remain almost in the same range. On the contrary, using a rhodium porphyrin bearing chlorine groups in the ortho-positions of the phenyl rings, the ratios increase, reaching higher values. These observations suggest the presence of different factors involved in determining the isomeric ratios. The electron-withdrawing effects of the substituents in the β-positions seem to influence the stereoselectivity giving the less hindered isomer while the chlorine bulky substituents in the ortho-phenyl positions can compensate this trend.
A facile synthesis of rhodium(III) porphyrin-silyls
Tse, Andy K.-S.,Wu, Bo-Mu,Mak, Thomas C.W.,Chan, Kin Shing
, p. 257 - 261 (2007/10/03)
Rhodium(III) porphyrin-silyls [Me3SiRhT(p-X)PP (X=H, Me)] were synthesized from the reactions of the rhodium(I) porphyrin anions, generated from the reduction of the rhodium(III) porphyrin chlorides with the sodium amalgam in toluene, with degassed Me3SiCl at room temperature. A single crystal structure of (5,10,15,20-tetraphenylporphyrinato)(trimethylsilyl)rhodium(III) (1) showed that the Rh-Si bond length is equal to 2.305 ?.
Photochemistry of (μ-tetraphenylporphyrinato)bis[dicarbonylrhodium(I)] in benzene - carbon tetrachloride mixture. Formation of chloro(tetraphenylporphyrinato)carbonylrhodium(III)
Hoshino, Mikio,Yasufuku, Katsutoshi
, p. 4408 - 4410 (2008/10/08)
Photolysis of (μ-tetraphenylporphyrinato)bis[dicarbonylrhodium(I)] (TPP[RhI(CO)2]2) in a 5:1 mixture of benzene and carbon tetrachloride gives rise to the formation of chloro(tetraphenylporphyrinato)carbonylrhodium(III) (Cl(TPP)RhIII(CO)). The quantum yield (Φ) for the photodecomposition of TPP[RhI(CO)2]2 is markedly dependent on the excitation wavelength (λ): Φ = 0.075 ± 0.04, λ -4, λ > 420 nm. The laser photolysis studies of TPP[RhICO)2]2 using the second (532 nm) and the third (355 nm) harmonic of a Nd-YAG laser reveal that neither the lowest singlet nor the triplet state is responsible for the photodecomposition of TPP[RhI(CO)2]2. The homolysis of the Rh(I)-N bond in the higher excited singlet states of TPP[RhI(CO)2]2 is considered to result in the formation of a transient species, TPP-[RhII(CO)2]. The assumption that TPP[RhII(CO)2]2 abstracts a chlorine atom from carbon tetrachloride gives an interpretation for the formation of Cl(TPP)RhIII(CO): (TPP)RhII(CO)2 + CCl4 → Cl(TPP)RhIII(CO) + CO + CCl3.
