- Electrocatalytic water oxidation by a water-soluble nickel porphyrin complex at neutral ph with low overpotential
-
The water-soluble cationic nickel(II) complex of meso-tetrakis(4-N-methylpyridyl)porphyrin (1) can electrocatalyze water oxidation to O2 in neutral aqueous solution (pH 7.0) with the onset of the catalytic wave appearing at 14;1.0 V (vs NHE). The homogeneous catalysis with 1 was verified. Catalyst 1 exhibited water oxidation activity in a pH range 2.0-8.0 and had a strict linear dependence of catalytic current on its concentration. After 10 h of constant potential electrolysis at 1.32 V (vs NHE), a negligible difference of the solution was observed by UV-vis. In addition, inspection of the working electrode by electrochemistry, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX) showed no sign of deposition of NiOx films. These results strongly argued that 1 is a real molecular electrocatalyst for water oxidation. The turnover frequency (TOF) for this process was 0.67 s-1 at 20 °C. On the basis of results from the kinetic isotope effect (KIE) and inhibition experiments, electrochemical studies in various buffer solutions with different anions and pHs, and DFT calculations, a catalytic cycle of 1 for water oxidation via a formally Ni(IV) species was proposed.
- Han, Yongzhen,Wu, Yizhen,Lai, Wenzhen,Cao, Rui
-
p. 5604 - 5613
(2015/06/16)
-
- Pharmaceutical compositions comprising porphyrins and some novel porphyrin derivatives
-
Tertrapyrrolic macrocycles selected from 5,10,15,20-tetraaryl-porphyrins and 5,10,15-triaryl-corrloes, wherein said aryl radical is a carboaryl, a heteroaryl or a mixed carboaryl-heteroaryl radical and at least two of said aryl radicals are positively charged, inhibit growth factor (e.g. bFGF, VEGF) receptor tyrosine kinase activity, and are useful for inhibition of cell proliferation mediated by growth factor receptor tyrosine kinase activity for example for inhibition of angiogenesis, or vascular smooth muscle cell proliferation in disorders including atherosclerosis, hyperthrophic heart failure and postsurfical restenosis, and of cell proliferation and migration in the treatment of primary tumors and metastasis. Some of the 5,10,15,20-tetraaryl-prophyrins are novel compounds.
- -
-
Page/Page column 20
(2010/02/06)
-
- Pulsed Irradiation of Water-soluble Porphyrins
-
Nanosecond laser flash photolysis and pulse radiolysis have been used to characterise the excited states and radicals of meso-tetraphenylporphyrin tetrasulphonic acid as the tetrasodium salt (Na4TPPS) and of meso-tetra-N-methylpyridylporphyrin as the tetra-p-toluenesulphonate (TMPyrP).After 347 nm irradiation, aqueous Na4TPPS forms triplet states (ΦT=0.76) and photoionises monophotonically (ΦI=0.029), while TMPyrP forms only triplets (ΦT=0.92) and does not photoionise.The difference and corrected spectra of the triplet states and the semi-oxidised and semi-reduced radicals of these molecules have been obtained.
- Bonnet, Raymond,Ridge, R. J.,Land, Edward J.,Sinclair, Roy S.,Tait, David,Truscott, T. George
-
p. 127 - 136
(2007/10/02)
-
