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[en] Geminate pair (anthracene...oxygen) was prepared by anthracene epoxide photolisys at 266 nm at 77 K in squalane and alcohol matrices. Anthracene fluorescence is quenched by oxygen via exchange mechanism. The quenching rate constant depends on the distance between partners in geminate pair and therefore the luminescence intensity can give the information about the distance distribution in geminate pairs (anthracene...oxygen) and its transformation in time. Main results: (1) Luminescence quenching method can follow the changing the distance distribution in time in geminate pairs (anthracene...oxygen) in a range of distances 4-10 A. (2) The approximation of continual diffusion has been shown to be adequate in describing of the kinetic curves for separation kinetics in geminate pairs. (3) The method proposed for determining of the diffusion coefficient of oxygen by the separation of geminate pairs allows one to measure the values of mobility up to D-1023 cm2 /s. (4) Oxygen diffusion coefficient in squalane at 77 K is equal 0.9*1023 cm2/s
[en] Highlights: • As-produced samples of SWNTs are metallic and semiconducting mixtures. • Metallic and semiconducting SWNTs can be separated via selective interactions. • Planar aromatic species selectively interact with metallic and semiconducting SWNTs. • Molecular tweezers of paired aromatic species are highly effective separation agents. • An appropriate molecular tweezers-solvent combination enables bulk separation. As-produced single-walled carbon nanotubes (SWNTs) are metallic and semiconducting mixtures. An anthracene mono-derivative with a long alkyl tail and a molecule with a tethered pair of anthracene species (bis-anthracene) in a “molecular tweezers”-like configuration were synthesized and evaluated for the separation of SWNTs. While the mono-derivative was incapable of the noncovalent functionalization–solubilization, the bis-anthracene was found to be very effective. The results suggest that molecular tweezers of a tethered pair of planar aromatic species can be coupled with the selection of a suitable solvent or solvent mixture for effective and efficient post-production separation of metallic and semiconducting SWNTs.
[en] Na/D2O/THF is highly effective in perdeuteration of anthracene-d10 and 9, 10-dibromoanthracene at the 9, 10-positions to give 9, 10-dihydro-9, 10-d2-anthracene-d10 and 9, 10-dihydro-9,9,10,10-d4-anthracene respectively. (author)
[en] The conductivity of alkali anthracene addition compounds of the general formula Mx (atc) with x=2.0 and = 1.5 was measured in dependence on pressure up to 400 MPa, shoving values in the range of 10-8 S/cm. A suitable apparatus is described. (authors)
[en] We have developed a new fluorescent sensor for Fe3+ based on anthracene moiety of hydroxyalkylamine. Fluorescent sensor 1 displayed highly selective and sensitive fluorescent 'turn-on' toward Fe3+ in acetonitrile solution. The 1:1 stoichiometry of sensor complex 1+Fe3+ was confirmed by Job's plots based on fluorescence emission titration. Furthermore, the binding sites of sensor complex 1+Fe3+ was properly identified from 1H NMR study
[en] The binding mode of anthryl derivatives to synthetic polynucleotides were investigated by various spectroscopic methods. The spectroscopic properties of anthracence with methylamine and methylethylenediamine side chains, complexed with poly(d(A-T)2) and poly(d(G-C)2), can be summarized as a red-shift, with a strong hypochromism in the absorption spectrum induced CD spectra, and a strong negative LD spectrum with an LDr magnitude comparable to the DNA absorption region. These observation indicate that anthracene moiety is inter calated between the nucleo-bases of poly(d(A-T)2) and poly(d(G-C)2). The side chains did not alter the spectroscopic properties, demonstrating that the binding mode was not affected by them. A strong energy transfer was observed from poly(d(A-T)2) and poly(d(I-C)2) but not from poly(d(G-C)2), as reported by Kumar et al. (J. Am. Chem. Soc. (1993) 115, 8547). Since the binding mode is the same for all the polynucleotides, the amine group of the guanine base, which protrudes into the minor groove of poly(d(G-C)2), is concluded to disrupt the energy transfer
[en] Present article is devoted to quantitative analysis of solvate chromic shift of electron absorption bands of average intensity. The quantitative assessment of solvate chromic shift of electron absorption bands of average intensity on the example of "1L_a absorption bands of anthracene solutions in the solvents of various physicochemical nature was conducted.
[en] It was well known that CT (Charge Transfer band) excitation of EDA (Electron Donor Acceptor) complex of Aromatic compound and Tetranitromethane (TNM) produces covalent adduct as the final product; however, it was not until the picosecond study on the Anthracene EDA complexes with Tetranitromethane that the dynamics associated with the covalent adduct formation and other related processes became quantitatively evaluated. According to the current understanding of the subject, picosecond excitation of EDA complex produces Contact Ion Pair (CIP) instantaneously, and this CIP is subject to two main competing processes; Ion-Pair collapse to form a covalent adduct and separation by solvent to form solvent separated Ion Pair (SSIP). In addition to these processes, Ion-pair exchange is possible with the added salt such as Tetra-n-butylammoniumperchlorate (TBA+P-) or Tetra-n-butyl-ammonium trinitromethide (TBA+T-). Previous picosecond study on the Anthracene EDA complexes with TNM employed a series of 9-X-anthracenes, where the substituents (X) of varying electrophilic character were used to modulate the ion-pair dynamics in various solvent with or without the added salts. Their work on the solvent effect and salt effect has revealed the importance of the ionic character of CIP in its solution dynamics.