Showing papers by "Raymond Bonnett published in 1987"
TL;DR: In this paper, the authors examined lignites of widely different origins and geological ages for the presence of iron porphyrins and found that they were detected in most but not all of the samples.
22 citations
TL;DR: In this paper, a correlation was found between the natural metal content and botanical origin, and the metal uptake by humic acid derived from each peat sample was also determined.
17 citations
14 citations
TL;DR: In this paper, the valley adducts of tetraethylpropentdyopent are formulated as the valley of the zinc-II complex, and the water and methanol derivatives are derived from the valley.
Abstract: The history of the propentdyopent problem is briefly summarised. Tetraethyl(methanol)propentdyopent and tetraethyl (water) propentdyopent are prepared from octaethylhaemin and from 3,3′,4,4′-tetraethyl-2,2′-methylenedipyrrole-5,5′-dicarboxylic acid under specified oxidative conditions, are interconverted under appropriate acidic conditions, and readily form the orange zinc(II) complex of tetraethylpropentdyopent. Arguments are advanced to show that the water and methanol derivatives are to be formulated as the valley adducts (18a, b) of tetraethylpropentdyopent.
11 citations
TL;DR: In this paper, the Z⇄E photoisomerisation of four α-unsubstituted pyrromethenones which are potential precursors of alkanol-propentdyopent adducts is studied using a direct n.m. spectroscopic approach in CD3OD-CDCl3.
Abstract: The Z⇄E photoisomerisation of four α-unsubstituted pyrromethenones which are potential precursors of alkanol–propentdyopent adducts is studied using a direct n.m.r. spectroscopic approach in CD3OD–CDCl3. Chemical-shift assignments are made with the help of n.O.e. and decoupling experiments. For the polyalkylpyrromethenones the photostationary state contains ca. 25% of the E isomer: a system with a β-ethoxycarbonyl group leads to 43%E isomer at photoequilibrium. The E isomers can be manipulated in solution without appreciable change, but thermodynamic equilibration to the Z isomer (ca. 99%) occurs on dry silica. A similar photoisomerisation of (4Z,15Z)-bilirubin IIIα in ND3–CD3OD leads to a photoequilibrated mixture containing 16% of (4E,15Z)-bilirubin IIIα.
9 citations
Patent•
26 Mar 1987
TL;DR: In this article, a meso-porphyrin compound is used to locate a porphyrin in the tumor and then illumination with light of a wavelength absorbed by the compound is provided.
Abstract: This invention provides for therapy of tumours susceptible to necrosis by a porphyrin when an appropriate porphyrin compound is administered to locate in the tumor followed by illumination with light of a wavelength absorbed by the compound, making use of meso-porphyrins of the formula: ##STR1## where n=1 to 3 and each substitutent R, the same or different and at the same or different position in its respective substituent phenyl ring or other aromatic group replacing that ring, is an hydroxy, amino or sulphydryl group, by association of said meso-porphyrins with a suitable pharmaceutical diluent or carrier.
9 citations
TL;DR: In this article, the photo-oxygenation of octaethyloxophlorin has been investigated under basic and under neutral conditions, and unstable intermediate stages are observed spectroscopically.
Abstract: The photo-oxygenation of octaethyloxophlorin has been investigated under basic and under neutral conditions. In both cases unstable intermediate stages are observed spectroscopically. In methanolic sodium methoxide the solution becomes bleached and tetraethyl(methanol)propentdyopent is a significant product. In neutral solutions (e.g. benzene–methanol) the major products are octaethyl-l5,15-dioxo-5,15-dihydroporphyrin (4) and octaethyl-19-formyl-21H,24H-bilin-1,15-dione (7), the formation of octaethyl-21H,24H-bilin-1,19-dione (6) being a minor pathway. A mechanistic rationalisation is proposed.
8 citations
TL;DR: In this paper, the distribution of metalloporphyrins in some petrographic components of a subbituminous coal (Janina, East High Silesian coal basin, Poland) were determined.
8 citations
TL;DR: In this paper, MNDO/3 calculations on substituted Z-propentdyopents, their anions and cations, and some propentdyopent adducts are reported.
Abstract: MINDO/3 (and in some cases MNDO) calculations on substituted Z-propentdyopents, their anions and cations, and some propentdyopent adducts are reported. Using the frontier orbital model, predictions of reactivity are made for the various systems, and are related to known experimental results.
1 citations
TL;DR: In this paper, the valley adducts of tetraethylpropentdyopent are formulated as the valley of the zinc-II complex, and the water and methanol derivatives are derived from the valley.
Abstract: The history of the propentdyopent problem is briefly summarised. Tetraethyl(methanol)propentdyopent and tetraethyl (water) propentdyopent are prepared from octaethylhaemin and from 3,3′,4,4′-tetraethyl-2,2′-methylenedipyrrole-5,5′-dicarboxylic acid under specified oxidative conditions, are interconverted under appropriate acidic conditions, and readily form the orange zinc(II) complex of tetraethylpropentdyopent. Arguments are advanced to show that the water and methanol derivatives are to be formulated as the valley adducts (18a, b) of tetraethylpropentdyopent.