525 research outputs found
Synthesis and Characterization of Nitroxide-Linked Ruthenium Complexes as Molecular Probes for Microheterogeneous Environments
No full textNitroxide-Labeled Ru(II) Polypyridyl Complexes as EPR Probes of Organized Systems. 3. Characterization of Starburst Dendrimers and Comparison to Photophysical Measurements
No full textInfrared spectroscopy of endohedral HD and D2 in C60
No full textWe report on the dynamics of two hydrogen isotopomers, D-2 and HD, trapped in the molecular cages of a fullerene C-60 molecule. We measured the infrared spectra and analyzed them using a spherical potential for a vibrating rotor. The potential, vibration-rotation Hamiltonian, and dipole moment parameters are compared with previously studied H-2@C-60 parameters [M. Ge, U. Nagel, D. Hiivonen, T. Room, S. Mamone, M. H. Levitt, M. Carravetta, Y. Murata, K. Komatsu, J. Y.-C. Chen, and N. J. Turro, J. Chem. Phys. 134, 054507 (2011)]. The isotropic part of the potential is similar for all three isotopomers. In HD@C-60, we observe mixing of the rotational states and an interference effect of the dipole moment terms due to the displacement of the HD rotation center from the fullerene cage cente
Infrared spectroscopy of endohedral HD and D2 in C60
No full textWe report on the dynamics of two hydrogen isotopomers, D2 and HD, trapped in the molecular cages of a fullerene C60 molecule. We measured the infrared spectra and analyzed them using a spherical potential for a vibrating rotor. The potential, vibration-rotation Hamiltonian, and dipole moment parameters are compared with previously studied H2@C 60 parameters [M. Ge, U. Nagel, D. Hvonen, T. Rm, S. Mamone, M. H. Levitt, M. Carravetta, Y. Murata, K. Komatsu, J. Y.-C. Chen, and N. J. Turro, J. Chem. Phys. 134, 054507 (2011)10.1063/1.3535598]. The isotropic part of the potential is similar for all three isotopomers. In HD@C60, we observe mixing of the rotational states and an interference effect of the dipole moment terms due to the displacement of the HD rotation center from the fullerene cage center. © 2011 American Institute of Physics
Pyridine ylide formation by capture of phenylchlorocarbene and tert-butylchlorocarbene. Reaction rates of an alkylchlorocarbene by laser flash photolysis
No full textPT: J; CR: BARCUS RL, 1986, J AM CHEM SOC, V108, P3928 CHATGILIALOGLU C, 1982, J AM CHEM SOC, V104, P5124 GOULD IR, 1985, TETRAHEDRON, V41, P1587 GRILLER D, 1984, J AM CHEM SOC, V106, P2227 LIU MTH, 1985, TETRAHEDRON LETT, V26, P3071 MOSS RA, 1981, TETRAHEDRON LETT, V38, P3749 SOUNDARARAJAN N, IN PRESS J AM CHEM S SOUNDARARAJAN N, IN PRESS TETRAHEDRON SOUNDARARAJAN N, UNPUB TURRO NJ, 1985, J ORG CHEM, V50, P4417 TURRO NJ, 1987, J AM CHEM SOC, V109, P2101 ZUGRAVESCU I, 1976, N YLID CHEM; NR: 12; TC: 144; J9: J AMER CHEM SOC; PG: 2; GA: P5279Source type: Electronic(1
Metalistería y numismática del Turro (Cacín) en los siglos VIII al XI
No full textThe author examines archeological pieces which form part of a prívate collection, that of the "Turro" hacienda in Cacín, Granada, situated near sorne ruins wher sigilleta· and other materials have been found. The pieces studied (a total of 7) come from the Higuerillas path: two copper rings, a fragment of a lamp-snuff or spatula, an arrow-tip, a broach, a lid and a shapeless ítem. A collection of andalusi coin s from the 8th to the 1 1t h century is also described. The study is of interest, since it provides data which help to illuminate aspects of the Late Middle Ages in the Granada area.El trabajo está confeccionado con materiales arqueológicos de una colección particular. Son de la cortijada del Turro (Cacín, Granada) cerca de unas ruinas donde se localizó sigillata y otros materiales. Los materiales que estudiamos son del pasaje de las Higuerillas con un total de 7 piezas: dos anillos de cobre, un fragmento de despabiladera de candil y espátula, una punta de flecha, un broche, una tapadera y un resto amorfo. Además se aporta un lote de monedas andalusíes de los siglos VIII al XI. El trabajo es interesante por las noticias que aportan y por completar otros aspectos de la alta Edad Media en las tierras granadinas
Photolysis of diazirines in the presence of C-60: A chemical probe for carbene
No full textPT: J; CR: AKASAKA T, 1999, J ORG CHEM, V64, P566 AKASAKA T, 1999, ORG LETT, V1, P1509 AN YZ, 1994, J ORG CHEM, V59, P2927 ANDERSON HL, 1994, ANGEW CHEM INT EDIT, V33, P1366 BINKLEY JS, 1980, J AM CHEM SOC, V102, P939 BONNEAU R, 1996, J AM CHEM SOC, V118, P7229 DIEDERICH F, 1994, CHEM SOC REV, P243 DIEDERICH F, 1994, NATURE, V369, P199 FRISCH MJ, 1988, PHYS REV A, V38, P3098 GANZER GA, 1986, J AM CHEM SOC, V108, P1517 GONZALEZ R, 1995, J ORG CHEM, V60, P2618 GRILLER D, 1982, J AM CHEM SOC, V104, P5549 GRILLER D, 1983, J ORG CHEM, V48, P1359 HIRSCH A, 1993, ANGEW CHEM INT EDIT, V32, P1138 HIRSCH A, 1993, CHEM BER, V126, P1061 HIRSCH A, 1994, CHEM FULLERENES HIRSCH A, 1999, FULLERENES RELATED S ISAACS L, 1993, HELV CHIM ACTA, V76, P2454 JANSSEN RAJ, 1995, J AM CHEM SOC, V117, P544 KOMATSU K, 1993, CHEM LETT, P2163 LEE C, 1988, PHYS REV B, V37, P785 LIU MTH, 1987, CHEM DIAZIRINES, V1 MARTIN N, 1998, CHEM REV, V98, P2527 SMITH AB, 1993, J AM CHEM SOC, V115, P5829 STEVENS IDR, 1990, J CHEM SOC P2, P661 SUZUKI T, 1991, SCIENCE, V254, P1186 SUZUKI T, 1992, J AM CHEM SOC, V114, P7301 SUZUKI T, 1994, J AM CHEM SOC, V116, P1359 TAYLOR R, 1993, NATURE, V363, P685 TAYLOR R, 1995, CHEM FULLERENES TOKUYAMA H, 1993, TETRAHEDRON LETT, V34, P7429 TSUDA M, 1993, TETRAHEDRON LETT, V34, P6911 TURRO NJ, 1980, J AM CHEM SOC, V102, P7576 TURRO NJ, 1982, J AM CHEM SOC, V104, P1754 VASELLA A, 1992, ANGEW CHEM INT EDIT, V31, P1388; NR: 35; TC: 8; J9: J AM CHEM SOC; PG: 2; GA: 340FPSource type: Electronic(1
Photolysis of 3-chlorodiazirine in the presence of alkenes. Kinetic evidence for intervention of a carbene-alkene intermediate in addition of chlorocarbene to alkene
No full textPT: J; CR: MOSS RA, 1978, J AM CHEM SOC, V100, P6788 MOSS RA, 1978, J CHEM SOC CHEM COMM, P755 MOSS RA, 1979, TETRAHEDRON LETT, P1277 MOSS RA, 1980, TETRAHEDRON LETT, V21, P2037 MOSS RA, 1981, TETRAHEDRON LETT, V22, P997 MOSS RA, 1983, TETRAHEDRON LETT, V24, P685 SU DTT, 1978, J AM CHEM SOC, V100, P1872 TOMIOKA H, 1980, J AM CHEM SOC, V102, P7123 TURRO NJ, 1980, J AM CHEM SOC, V102, P7576 TURRO NJ, 1982, J AM CHEM SOC, V104, P1754; NR: 10; TC: 48; J9: J AMER CHEM SOC; PG: 3; GA: SA583Source type: Electronic(1
Can H-2 inside C-60 communicate with the outside world?
No full textThe quenching rate constants of singlet oxygen by C-60, H-2@C-60, D-2@C-60, H-2, and D-2 in solution were measured. The presence of a hydrogen (H-2@C-60) or deuterium (D-2@C-60) molecule inside the fullerene did not produce any observable effect based on triplet lifetime or EPR measurements. However, a remarkable effect was found for the O-1(2) quenching by C-60, H-2@C-60, D-2@C-60, H-2, and D-2. Singlet oxygen was generated by photosensitization or by thermal decomposition of naphthalene endoperoxide derivatives. Comparison of the rate constants for quenching Of O-1(2) by H-2@C-60 and D-2@C-60 demonstrates a significant vibrational interaction between oxygen and H-2 inside the fullerene. The quenching rate constant for H-2 is 1 order of magnitude higher than that of D2, in agreement with the results observed for the quenching Of O-1(2) with H-2@C-60 or D-2@C-60
Demonstration of a chemical transformation inside a fullerene. The reversible conversion of the allotropes of H-2@C-60
No full textThe interconversion of the two allotropes of the hydrogen molecule (para-H(2) and ortho-H(2)) incarcerated inside the fullerene C(60) is reported (oH(2)@C(60), respectively). For conversion, oH(2)@C(60) was adsorbed at the external surface of the zeolite NaY and immersed into liquid oxygen at 77 K. Equilibrium was reached in less than 0.5 h. Rapid removal of oxygen provides a sample of enriched pH(2)@C(60) that is stable for many days in the absence of paramagnetic catalysts (half-life similar to 15 days). Enriched pH(2)@C(60) is nonvolatile and soluble in organic solvents. At room temperature in the presence of a paramagnetic catalyst (dissolved 02 or the nitroxide Tempo) a slow back conversion into oH2@C60 was observed by (1)H NMR. A bimolecular rate constant for conversion of pH2@C60 to oH(2)@C(60) using Tempo of k(Tempo) similar to 4 x 10(-5) M(-1) s(-1) was observed, which is approximately 3 orders of magnitudes slower than that for dissolved pH(2) in organic solvents which is not protected by the C(60) shell
- …
