Picosecond study of the luminescence and transient absorption of methylene blue–polynucleotide complexes

Abstract

Transient absorption signals observed after picosecond laser excitation of Methylene Blue (MB+) bound to double-stranded polydeoxyguanylic-deoxycytidylic acid { poly[d(G-C)].poly [d(G-C)]} are assigned to the dye's singlet excited state reacting with a lifetime of 4 ps to form the electron-transfer product (MB'.G'+) which itself decays with a lifetime of 130 ps.

Interaction of the Antitumoral Drug Pazelliptine with Polynucleotides: A Subpicosecond Transient Absorption Study

“…Among these few examples one notes the complexes of phenotiazinium dyes, methylene blue and thionine, formed with mono- and polynucleotides. Initially, the fast component detected in the decay of differential absorption of complexed methylene blue has been attributed to an electron or a hydrogen atom transfer from guanine to the excited dye. However, the systematic investigation of the transient differential absorption between 400 and 850 nm has shown no traces of semireduced methylene blue, the radical which would be formed by the proposed electron transfer .…”

Novel photochemistry of leuco-Methylene Blue

“…The above method of analysis is just one example of many photochemical processes that have been studied in which Methylene Blue has been used as the photosensitiser. Most of the photochemistry associated with Methylene Blue is not due to its first excited singlet state, which has a very short lifetime (358 ps), 11,12 but instead due to its long lived (4.5 ms), 13 low energy (138 kJ mol 21 ), 14 triplet state which is formed with a high quantum yield (0.52). 14 In contrast to the highly coloured, oxidized form of Methylene Blue, MB + , the photochemistry of its colourless reduced form, LMB, has not been the subject of much, if any, study.…”

Structure and absolute stereochemistry of the four N-phenylprotoporphyrin IX regioisomers isolated from phenylhydrazine-treated myoglobin

“…1982, 257, 4404-4411. (15) Delaforge, M.; Battioni, P.; Mahy, J. P.; Mansuy, D. Chem.-Biol. Interact.…”