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Hydrogen bond
About: Hydrogen bond is a research topic. Over the lifetime, 57701 publications have been published within this topic receiving 1306326 citations.
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TL;DR: A Friedel-Crafts benzylation of arenes with benzyl fluorides has been developed and produces 1,1-diaryl alkanes in good yield under mild conditions without the need for a transition metal or a strong Lewis acid.
Abstract: A Friedel–Crafts benzylation of arenes with benzyl fluorides has been developed. The reaction produces 1,1-diaryl alkanes in good yield under mild conditions without the need for a transition metal or a strong Lewis acid. A mechanism involving activation of the CF bond through hydrogen bonding is proposed. This mode of activation enables the selective reaction of benzylic CF bonds in the presence of other benzylic leaving groups.
175 citations
TL;DR: In this paper, neutral linear centrosymmetric XeHXe+H, HXeD, and DXeD were assigned as the new species responsible for these absorptions.
Abstract: Photolysis of hydrogen halides (and some other hydrogen containing small molecules) in solid Xe yields in a two step process charged centers, one of them being XeHXe+. Annealing of the irradiated doped solids produces, in addition to H–Xe–Y (Y=Cl, Br, or I) species characterized by us previously, a fairly strong doublet at 1181 and 1166 cm−1 and a weak absorption at 701 cm−1. Deuterated precursors yield a doublet at 846 and 856 cm−1. Also peaks belonging to mixed H/D form are found, indicating that the absorbing species contains two H/D atoms. The new species responsible for these absorptions are assigned as neutral linear centrosymmetric HXeH, HXeD, and DXeD. The nature of the bonding can be understood in terms of the resonance between the two ionic forms HXe+H− and H−Xe+H, analogously to the valence bond description of the well known XeF2. The pseudopotential (LANL1DZ) ab initio calculations at the MP2 level are in good agreement with the observed spectra.
175 citations
TL;DR: In this article, the authors used an independently tunable picosecond infrared pulse to study the growth and decay of the hydrogen-bonded HO groups of ethanol oligomers (solvent CCl4).
Abstract: Internal, hydrogen bonded OH groups of ethanol oligomers (solvent CCl4) are vibrationally excited by intense picosecond pulses at 3320 cm−1. The transient band shape observed in the OH stretching region (3000 to 3700 cm−1) is monitored by an independently tunable picosecond infrared pulse. The bands in this region are direct probes of hydrogen bridges. The time dependent growth and decay of these bands provides strong evidence for rapid bond breaking with a vibrational predissociation time of ≊5 ps, and for partial reassociation with a time constant of ≊20 ps.
174 citations
174 citations
TL;DR: The observed hydrogen bonding pattern provides experimental evidence for the previously proposed proton exit pathway involving the heme propionate and a chain of water molecules.
174 citations