Showing papers by "Raymond Bonnett published in 1983"
TL;DR: Nanosecond laser flash photolysis and pulse radiolysis have been used to generate and characterise the triplet state, and semioxidised and semireduced radicals of haematoporphyrin and three 0‐acyl compounds derived from it.
Abstract: — Nanosecond laser flash photolysis and pulse radiolysis have been used to generate and characterise the triplet state, and semioxidised and semireduced radicals of haematoporphyrin, and three 0-acyl compounds derived from it (the monoacetate, the diacetate and the disuccinate).
After 347 nm irradiation in water containing 2% Triton X-100, haematoporphyrin forms the triplet state (φT= 0.92) and photoionises monophotonically (φI= 0.03). For the O-acyl derivatives, φT approaches unity and photoionisation is reduced. In acetone the triplet yield of all four compounds are close to unity. The difference and corrected spectra for the triplet species are presented and decay rates (k1˜104s-1) and oxygen quenching constants (kQ˜1.5times109M-1s-1) for the triplet state have been measured. The difference and corrected spectra for the semi-reduced species in methanol and semi-oxidised species in aqueous Triton X-100 are presented.
The photophysical characteristics in fluid solution of haematoporphyrin and its 0-acyl derivatives are rather similar to those previously recorded for other photosensitising porphyrins.
72 citations
TL;DR: The preparation of the difluoroboron(III) complex (4 ) of octaethyl-21 H,24 H -bilin-1,19-dione is described in this paper.
47 citations
TL;DR: In this paper, 1-Phenylisoindole reacts with toluene-p-diazonium chloride to give the azo derivative formed by electrophilic substitution at the free α position.
25 citations
TL;DR: In this paper, the reaction of octaethylporphyrin with hypofluorous acid and with permaleic acid gives a mono-oxygen adduct formulated as the porphyrin Noxide, a novel chemical system.
Abstract: The reaction of octaethylporphyrin with hypofluorous acid and with permaleic acid gives a mono-oxygen adduct formulated as the porphyrin N-oxide, a novel chemical system. Octaethylporphyrin N-oxide is a sensitive molecule: it is gradually converted into octaethylporphyrin when manipulated under ordinary conditions. Examples of deoxygenation, nucleophilic attack at C-5, and metal complexation are described.
13 citations
TL;DR: In this article, evidence is presented for the occurrence in certain lignites of iron porphyrins, including the iron complex of mesoporphyrin or its isomers.
Abstract: Evidence is presented for the occurrence in certain lignites of iron porphyrins, including the iron complex of mesoporphyrin or its isomers.
12 citations
TL;DR: In this paper, a mixture of bilirubin IXα and octaethyl-10,23-dihydro-21H,24H-bilin-1,19-dione was used to identify the products of the crossed pyrrole exchange reaction.
Abstract: Acid treatment of a mixture of bilirubin IXα (1) and octaethyl-10,23-dihydro-21H,24H-bilin-1,19-dione (7), followed by dehydrogenation and esterification gives biliverdin IXα, biliverdin XIIIα and biliverdin IIIα (as the dimethyl esters, 2, 3, 4, respectively), and octaethylbilindione (8), together with two minor verdins of intermediate polarity. These are identified as the products of the crossed pyrrole exchange reaction, which are 8-carboxyethyl-12,13,17,18-tetraethyl-2, 7-dimethyl-3-vinyl-21H,24H-bilin-1,19-dione methyl ester (9) and 8-carboxyethyl-12,13,17,18-tetra-ethyl-3,7-dimethyl-2-vinyl-21H,24H-bilin-1,19-dione methyl ester (10). An improved preparation of bilirubin XIIIα (5) and bilirubin IIIα (6) is described and the products are crystallised and characterised. The NMR spectra of bilirubin XIIIα and IIIα are recorded in a polar aprotic solvent (DMSO-d6) at 400 MHz, and certain unusual features are discussed.
10 citations
Journal Article•
TL;DR: Identification of porphyrines de fer dans trois lignites including le complexe du fer avec la mesoporphyrine ou avec ses isomeres as discussed by the authors.
Abstract: Identification de porphyrines de fer dans trois lignites incluant le complexe du fer avec la mesoporphyrine ou avec ses isomeres
9 citations