BRADFORD SCHOLARS

    • Sign in
    View Item 
    •   Bradford Scholars
    • Life Sciences
    • Life Sciences Publications
    • View Item
    •   Bradford Scholars
    • Life Sciences
    • Life Sciences Publications
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Bradford ScholarsCommunitiesAuthorsTitlesSubjectsPublication DateThis CollectionAuthorsTitlesSubjectsPublication Date

    My Account

    Sign in

    HELP

    Bradford Scholars FAQsCopyright Fact SheetPolicies Fact SheetDeposit Terms and ConditionsDigital Preservation Policy

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    H-bond acceptor parameters for anions

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    View/Open
    Pike_JACS_Final.pdf (1.331Mb)
    Download
    Publication date
    2017-05
    Author
    Pike, Sarah J.
    Hutchinson, J.J.
    Hunter, C.A.
    Keyword
    H-bonded complexes
    Anionic H-bond acceptors (HBAs)
    Neutral H-bond donors (HBDs)
    Anions
    H-bond parameters
    Rights
    © 2017 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
    Peer-Reviewed
    Yes
    
    Metadata
    Show full item record
    Abstract
    UV/vis absorption titrations have been used to investigate the formation of H-bonded complexes between anionic H-bond acceptors (HBAs) and neutral H-bond donors (HBDs) in organic solvents. Complexes formed by three different HBDs with 15 different anions were studied in chloroform and in acetonitrile. The data were used to determine self-consistent HBA parameters (β) for chloride, bromide, iodide, phosphate diester, acetate, benzoate, perrhenate, nitrate, triflimide, perchlorate, hexafluorophosphate, hydrogen sulfate, methyl sulfonate, triflate, and perfluorobutyl sulfonate. The results demonstrate the transferability of H-bond parameters for anions between different solvents and different HBD partners, allowing reliable prediction of anion recognition properties in other scenarios. Carboxylates are the strongest HBAs studied, with β parameters (≈ 15) that are significantly higher than those of neutral organic HBAs, and the non-coordinating anion hexafluorophosphate is the weakest acceptor, with a β parameter comparable to that of pyridine. The effects of ion pairing with the counter-cation were found to be negligible, provided small polar cations were avoided in the less polar solvent (chloroform). There is no correlation between the H-bonding properties of the anions and the pKa values of the conjugate acids.
    URI
    http://hdl.handle.net/10454/17666
    Version
    Published version
    Citation
    Pike SJ, Hutchinson JJ and Hunter CA (2017) H-bond acceptor parameters for anions. Journal of the American Chemical Society. 139(19): 6700-6706.
    Link to publisher’s version
    https://doi.org/10.1021/jacs.7b02008
    Type
    Article
    Collections
    Life Sciences Publications

    entitlement

     

    Related items

    Showing items related by title, author, creator and subject.

    • Thumbnail

      Nitrofurantoin-melamine monohydrate (cocrystal hydrate): Probing the role of H-bonding on the structure and properties using quantum chemical calculations and vibrational spectroscopy

      Khan, E.; Shukla, A.; Jhariya, Aditya N.; Tandon, P.; Vangala, Venu R. (2019-10-05)
      Cocrystal monohydrate of nitrofurantoin (NF) with melamine (MELA) has been studied as NF is an antibacterial drug used for the treatment of urinary tract infections. The structure of nitrofurantoin-melamine-monohydrate (NF-MELA-H2O) is characterized by FT-IR and FT-Raman spectroscopy. The energies and vibrational frequencies of the optimized structures calculated using quantum chemical calculations. Supported by normal coordinate analyses and potential energy distributions (PEDs), the complete vibrational assignments recommended for the observed fundamentals of cocrystal hydrate. With the aim of inclusion of all the H-bond interactions, dimer of NF-MELA-H2O has been studied as only two molecules of cocrystal hydrate are present in the unit cell. By the study of dimeric model consistent assignment of the FT-IR and FT-Raman spectrum obtained. H-bonds are of essential importance in an extensive range of molecular sciences. The vibrational analyses depict existence of H-bonding (O-H⋯N) between water O-H and pyridyl N atom of MELA in both monomer and dimer. To probe the strength and nature of H-bonding in monomer and dimer, topological parameters such as electron density (ρBCP), Laplacian of electron density (∇2ρBCP), total electron energy density (HBCP) and H-bond energy (EHB) at bond critical points (BCP) are evaluated by quantum theory of atoms in molecules (QTAIM). Natural bond orbitals (NBOs) analyses are carried out to study especially the intra and intermolecular H-bonding and their second order stabilization energy (E(2)). The value of HOMO-LUMO energy band gap for NF-MELA-H2O (monomer and dimer both) is less than NF, showing more chemical reactivity for NF-MELA-H2O. Chemical reactivity has been described with the assistance of electronic descriptors. Global electrophilicity index (ω = 7.3992 eV) shows that NF-MELA-H2O behaves as a strong electrophile than NF. The local reactivity descriptors analyses such as Fukui functions, local softnesses and electrophilicity indices performed to determine the reactive sites within NF-MELA-H2O. In MEP map of NF-MELA (monomer and dimer) electronegative regions are about NO2 and C=O group of NF, although the electropositive regions are around NH2, N-H group and H2O molecule. Molar refractivity (MR) value of NF-MELA-H2O (monomer and dimer) lies within the range set by Lipinski's modified rules. This study could set as an example to study the H-bond interactions in pharmaceutical cocrystals.
    • Thumbnail

      Study of molecular structure, chemical reactivity and H-bonding interactions in the cocrystal of nitrofurantoin with urea

      Khan, E.; Shukla, A.; Jadav, Niten B.; Telford, Richard; Ayala, A.P.; Tandon, P.; Vangala, Venu R. (2017)
      The cocrystal of nitrofurantoin with urea (C8H6N4O5)·(CH4N2O), a non-ionic supramolecular complex, has been studied. Nitrofurantoin (NF) is a widely used antibacterial drug for the oral treatment of infections of the urinary tract. Characterization of the cocrystal of nitrofurantoin with urea (NF–urea) was performed spectroscopically by employing FT-IR, FT- and dispersive-Raman, and CP-MAS solid-state 13C NMR techniques, along with quantum chemical calculations. With the purpose of having a better understanding of H-bonding (inter- and intra-molecular), two different models (monomer and monomer + 3urea) of the NF–urea cocrystal were prepared. The fundamental vibrational modes were characterized depending on their potential energy distribution (PED). A combined experimental and theoretical wavenumber study proved the existence of the cocrystal. The presence and nature of H-bonds present in the molecules were ascertained using quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis. As the HOMO–LUMO gap defines the reactivity of a molecule, and this gap is more for the API than the cocrystal, this implies that the cocrystal is more reactive. Global descriptors were calculated to understand the chemical reactivity of the cocrystal and NF. Local reactivity descriptors such as Fukui functions, local softness and electrophilicity indices were analysed to determine the reactive sites within the molecule. The comparison between NF–urea (monomer) and NF showed that the cocrystal has improved overall reactivity, which is affected by the increased intermolecular hydrogen bond strength. The docking studies revealed that the active sites (C[double bond, length as m-dash]O, N–H, NO2, N–N) of NF showed best binding energies of −4.89 kcal mol−1 and −5.56 kcal mol−1 for MUL and 1EGO toxin, respectively, which are bacterial proteins of Escherichia coli. This cocrystal could potentially work as an exemplar system to understand H-bond interactions in biomolecules.
    • Thumbnail

      H-bond donor parameters for cations

      Pike, Sarah J.; Lavagnini, E.; Varley, L.M.; Cook, J.L.; Hunter, C.A. (2019)
      UV/Vis absorption and NMR spectroscopy titrations have been used to investigate the formation of complexes between cations and neutral H-bond acceptors in organic solvents. Complexes formed by two different H-bond acceptors with fifteen different cations were studied in acetone and in acetonitrile. The effects of water and ion pairing with the counter-anion were found to be negligible in the two polar solvents employed for this study. The data were used to determine self-consistent H-bond donor parameters (α) for a series of organic and inorganic cations; guanidinium, primary, tertiary and quaternary ammonium, imidazolium, methylpyridinium, lithium, sodium, potassium, rubidium and caesium. The results demonstrate the transferability of α parameters for cations between different solvents and different H-bond acceptor partners, allowing reliable prediction of cation recognition properties in different environments. Lithium and protonated nitrogen cations form the most stable complexes, but the α parameter is only 5.0, which is similar to the neutral H-bond donor 3-trifluoromethyl, 4-nitrophenol (α = 5.1). Quaternary ammonium is the weakest H-bond donor investigated with an α value of 2.7, which is comparable to an alcohol. The α parameters for alkali metal cations decrease down the group from 5.0 (Li+) to 3.5 (Cs+).
    DSpace software (copyright © 2002 - 2023)  DuraSpace
    Quick Guide | Contact Us
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.