- INVESTIGATION OF THE DIMERIZATION OF ACRIDINE RADICAL ANIONS BY ELECTROCHEMICAL METHODS
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The electrochemical reduction of acridine (dimethylformamide (DMF) and Bu4NClO4) was investigated by differential cyclic voltammetry and controlled-potential electrolysis.The experimental data (dimerization rate constant and yield of the 9,9' dimer) agreed with the theoretically calculated ones.
- Gul'tyai, V. P.,Mendkovich, A. S.,Rubinskaja, T. Ya.,Rusakov, A. I.
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- Stoichiometrically sensitized decarboxylation occurring in the two-component molecular crystals of aza aromatic compounds and aralkyl carboxylic acids
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Highly selective photodecarboxylation could be achieved by utilizing a series of two-component molecular crystals of aralkyl carboxylic acids such as 3-indolepropionic acid (a) and 1-naphthylacetic acid (b) combined with acridine (1) or phenanthridine (2) as an electron acceptor. The 1:1 hydrogen bonded crystals were prepared by recrystallization from the solutions. Irradiation of the crystals at -70°C caused highly selective decarboxylation to give corresponding decarboxylated compounds alone in nearly quantitative yields, due to a smaller thermal motion of the radical species in the crystal lattice. Upon irradiating a crystal, a carboxylate radical and hydroacridine or hydrophenanthridine radical are produced via electron transfer from the acid to 1 or 2 and subsequent proton transfer followed by decarboxylation. Next hydrogen abstraction by an active aralkyl radical occurs in highest priority over the shortest distance of 3.2-3.5 A? resulting in the formation of a corresponding decarboxylated product and the regeneration of 1 or 2. Occurrence of radical coupling is low due to the longer coupling distance of 4.5-6.5 A? estimated from the crystallographic data of the starting two-component molecular crystals. The hydrogen abstraction path in the crystal lattice could be confirmed by the reaction of a deuterated crystal 1 · bD in which the CO2H group was replaced by CO2D, giving a deuterated 1-methyl(CH2D)naphthalene as a product. Regeneration of 1 or 2 means that the acceptor plays the role of a stoichiometrical sensitizer, which can act in only one cycle, retaining the initial crystal structure. Such a stoichiometrical sensitization is a novel photochemical process, which occurs specifically in the solid state.
- Koshima, Hideko,Ding, Kuiling,Chisaka, Yosuke,Matsuura, Teruo,Miyahara, Ikuko,Hirotsu, Ken
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p. 10317 - 10324
(2007/10/03)
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- Novel photochemical coupling of hindered phenols in the presence of acridine mechanistically probed by CIDEP
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Irradiation of hindered phenols in the presence of acridine as a light absorber gives bisphenols and biacridane.CIDEP study establishes the path of hydrogen abstraction by the triplet acridine.The overall mechanism is proposed by the product analysis and the CIDEP studies.
- Okada, Keiji,Okubo, Katsura,Oda, Masaji,Murai, Hisano
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p. 845 - 846
(2007/10/03)
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- PHOTODECARBOXYLATION OF UNMODIFIED CARBOXYLIC ACIDS WITH USE OF AZA AROMATIC COMPOUNDS
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A very simple procedure for photodecarboxylation of intact carboxylic acids leading to alkanes is developed with use of aza aromatic compounds as light absorbers and t-BuSH as a hydrogen donor.
- Okada, Keiji,Okubo, Katsura,Oda, Masaji
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p. 6733 - 6736
(2007/10/02)
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- Synthesis of hexacarbonyl derivatives of group 5 metals and electron-transfer processes. Crystal and molecular structure of tetracarbonyl(1,2-bis(diphenylphosphino)ethane)iodotantalum
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Vanadium, niobium, and tantalum hexacarbonylmetalate(-I) derivatives of several heterocyclic nitrogen bases, RnB[M(CO)6]n (R = H, Me; n = 1, 2), have been synthesized. In some cases an electron transfer from the hexacarbonylmetalate to the protonated or methylated BRnn+ cation has been observed. Pyridinium halides react with Na[M(CO)6] (M = Nb, Ta) in the presence of 1 equiv of 1,2-bis(diphenylphosphino)ethane (diphos) to give high yields of the halo tetracarbonyl derivatives MX(CO)4(diphos). The red-orange TaI(CO)4(diphos) complex has been studied by X-ray diffraction methods. Crystal data: space group P21/n; Mr 818.3; a = 14.864 (10) ?, b = 9.875 (7) ?, c = 19.335 (13) ?; β = 105.61 (2)°; U = 2733 (3) ?3; Z = 4; Dcalcd = 1.988 g cm-3; F(000) = 1568; μ(Mo Kα) = 52.4 cm-1. The geometry of the seven-coordinate tantalum atom is best described as a capped trigonal prism with the iodide ligand in the capping position. By reaction of Na[Ta(CO)6] with 1 equiv of hydrogen chloride and diphos in toluene, the hydride TaH(CO)4(diphos) has been isolated in good yield.
- Calderazzo, Fausto,Pampaloni, Guido,Pelizzi, Giancarlo,Vitali, Francesca
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p. 1083 - 1092
(2008/10/08)
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