title: Hydrogen Atomic Positions of O-H···O Hydrogen Bonds in Solution and in the Solid State: The Synergy of Quantum Chemical Calculations with ¹H-NMR Chemical Shifts and X-ray Diffraction Methods.
abstract: The exact knowledge of hydrogen atomic positions of O-H···O hydrogen bonds in solution and in the solid state has been a major challenge in structural and physical organic chemistry. The objective of this review article is to summarize recent developments in the refinement of labile hydrogen positions with the use of: (i) density functional theory (DFT) calculations after a structure has been determined by X-ray from single crystals or from powders; (ii) ¹H-NMR chemical shifts as constraints in DFT calculations, and (iii) use of root-mean-square deviation between experimentally determined and DFT calculated ¹H-NMR chemical shifts considering the great sensitivity of ¹H-NMR shielding to hydrogen bonding properties.
authors.affiliation: Section of Organic Chemistry & Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-45110, Greece. msiskos@cc.uoi.gr.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Siskos
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Biological and Chemical Sciences, University of Karachi, Karachi 75270, Pakistan. iqbalhej@yahoo.com.
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
authors.affiliation: Section of Organic Chemistry & Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-45110, Greece. igeroth@uoi.gr.|H.E.J. Research Institute of Chemistry, International Center for Biological and Chemical Sciences, University of Karachi, Karachi 75270, Pakistan. igeroth@uoi.gr.
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Gerothanassis
mesh_terms: D006859:Hydrogen; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D066244:Proton Magnetic Resonance Spectroscopy; D011789:Quantum Theory; D012996:Solutions; D014961:X-Ray Diffraction
chemical_list: D012996:Solutions; D006859:Hydrogen
keywords: DFT; NMR; X-ray diffraction; chemical shifts; hydrogen bonding