48,198 research outputs found
Silver-Mediated Direct sp(3) C-H Bond Functionalization
No full textDirect sp(3) C-H bond functionalization is an efficient, straightforward, and powerful method to construct new C-X (X = C, N, F, S) bonds from nonfunctionalized aliphatic motif of organic molecules, which has been used in late-stage modification of complex molecules. In this chapter, the recent developments of silver-mediated direct sp(3) C-H functionalizations are reviewed, categorized by C-C bond formation (C-H insertion), C-N bond formation (intramolecular and intermolecular amination/amidation), C-F bond formation, and C-S bond formation.SCI(E)[email protected]
Letter from C. H. Gensler, Havasupai Agency to Carl Hayden
No full textLetter from C. H. Gensler expressing concern on behalf of the Havasupai Tribe regarding the proposed park boundaries
Letter from Carl Hayden to C. H. Gensler
No full textLetter from Carl Hayden to C. H. Gensler informing him of the proposed Grand Canyon National Park bill
Letter from C. H. Gensler, Havasupai Agency to Carl Hayden
No full textLetter from C. H. Gensler to Carl Hayden asking for a meeting in regards to the Havasupai pasture land in light of the national park bill
Letter from Carl T. Hayden to C. H. Gensler, Havasupai Reservation
No full textLetter from Carl T. Hayden to C. H. Gensler, Havasupai Indian Reservation, regarding Hualapai and Cataract Canyons geography
Citations of the author H C Rajpoot
No full textThe list of the articles, research papers, theses, and book chapters globally citing the author H. C. Rajpoot</p
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
VIBRATIONALLY EXCITED CH
No full textAuthor Institution: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138; Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138.Following the detection of the linear carbon chain radical CH in space, many rotational lines in the electronic ground state have been observed in a low pressure discharge at millimeter wavelengths} \underline{\textbf{197}}, 1 (1999).} and in a supersonic molecular beam at centimeter wavelengths} \underline{\textbf{122}}, 174308 (2005).}. In the course of a laboratory search for new reactive hydrocarbon molecules with 6 carbon atoms, several series of harmonically related lines with rotational constants near that of CH in the ground vibrational state were observed in the millimeter-wave band. On the basis of the close agreement in rotational constants and intensities, two of the series were assigned to and states of a low-lying excited bending vibrational level of CH. The standard Hamiltonian with five spectroscopic constants reproduces the observed rotational spectrum of the state, but several high-order distortion terms in the spin-rotation interaction are needed to reproduce the spectrum of the state of CH and CD. From the measured intensities of the rotational lines it appears that the state lies very close to ground but the state lies much higher in energy. A brief summary of the laboratory spectrum and applications to the astronomical observations will be presented
MICROWAVE SPECTROSCOPY OF TWO ISOELECTRONIC RADICALS: 2,4,6-HEPTATRIYNYL, , AND 2,4-HEXADIYNYLNITRILE,
No full textAuthor Institution: Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138; Division of Engineering and Applied Sciences, Harvard, Cambridge, MA; Department of Chemistry, Wesleyan University, Middletown, CTThe isoelectronic pair of radicals 2,4,6-heptatriynyl, , and 2,4-hexadiynylnitrile, , were produced in a pulsed discharge supersonic jet and detected by Fourier transform microwave spectroscopy. Seven rotational transitions of the heptatriynyl radical from to 10 and six rotational transitions of the hexadiynyl-nitrile radical from to 9 in the ladder were observed between 6 and 17 GHz. For each species, over 50 hyperline components were measured and assigned with an uncertainty of 5 kHz. Precise rotational, centrifugal distortion, spin-rotation, and various hyperfine coupling constants were determined for both and
AN EXHAUSTIVE ISOTOPIC STUDY OF THE ABUNDANT ASTRONOMICAL MOLECULE CYCLOPROPENYLIDENE, c-CH
No full textAuthor Institution: Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, and School of Engineering \& Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138Cyclopropenylidene, c-CH, is the most widely distributed ring in our galaxy; it has been detected in more than 50 astronomical sources, and its isotopic species c-CHD has been observed towards several dense cores in cold dark clouds. Because of the high observed abundance and large deuterium fractionation for this small hydrocarbon ring, other isotopic species of c-CH may be good candidates for astronomical detection. For these reasons, an exhaustive isotopic study of c-CH has now been undertaken in which rotational spectra of c-CD, c-CHD, and the carbon--13 isotopic species of c-CHD and c-CH have been detected in the centimeter-wave band by Fourier transform microwave (FTM) spectroscopy between 10 and 40~GHz. For c-CD, millimeter- and submillimeter-wave spectra were subsequently measured between 140 and 400~GHz. Rotational and centrifugal distortion constants derived either from previous measurements or those predicted from theory are compared with the precise constants determined here. % ######################################################################
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