1
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Jin PB, Luo QC, Gransbury GK, Vitorica-Yrezabal IJ, Hajdu T, Strashnov I, McInnes EJL, Winpenny REP, Chilton NF, Mills DP, Zheng YZ. Thermally Stable Terbium(II) and Dysprosium(II) Bis-amidinate Complexes. J Am Chem Soc 2023; 145:27993-28009. [PMID: 37997752 PMCID: PMC10755703 DOI: 10.1021/jacs.3c07978] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023]
Abstract
The thermostable four-coordinate divalent lanthanide (Ln) bis-amidinate complexes [Ln(Piso)2] (Ln = Tb, Dy; Piso = {(NDipp)2CtBu}, Dipp = C6H3iPr2-2,6) were prepared by the reduction of parent five-coordinate Ln(III) precursors [Ln(Piso)2I] (Ln = Tb, Dy) with KC8; halide abstraction of [Ln(Piso)2I] with [H(SiEt3)2][B(C6F5)] gave the respective Ln(III) complexes [Ln(Piso)2][B(C6F5)]. All complexes were characterized by X-ray diffraction, ICP-MS, elemental analysis, SQUID magnetometry, UV-vis-NIR, ATR-IR, NMR, and EPR spectroscopy and ab initio CASSCF-SO calculations. These data consistently show that [Ln(Piso)2] formally exhibit Ln(II) centers with 4fn5dz21 (Ln = Tb, n = 8; Dy, n = 9) valence electron configurations. We show that simple assignments of the f-d coupling to either L-S or J-s schemes are an oversimplification, especially in the presence of significant crystal field splitting. The coordination geometry of [Ln(Piso)2] is intermediate between square planar and tetrahedral. Projecting from the quaternary carbon atoms of the CN2 ligand backbones shows near-linear C···Ln···C arrangements. This results in strong axial ligand fields to give effective energy barriers to magnetic reversal of 1920(91) K for the Tb(II) analogue and 1964(48) K for Dy(II), the highest values observed for mononuclear Ln(II) single-molecule magnets, eclipsing 1738 K for [Tb(C5iPr5)2]. We tentatively attribute the fast zero-field magnetic relaxation for these complexes at low temperatures to transverse fields, resulting in considerable mixing of mJ states.
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Affiliation(s)
- Peng-Bo Jin
- Frontier
Institute of Science and Technology (FIST), State Key Laboratory of
Electrical Insulation and Power Equipment, MOE Key Laboratory for
Nonequilibrium Synthesis of Condensed Matter, Xi’an Key Laboratory
of Electronic Devices and Materials Chemistry and School of Chemistry, Xi’an Jiaotong University, 99 Yanxiang Road, Xi’an, Shaanxi 710054, P. R. China
| | - Qian-Cheng Luo
- Frontier
Institute of Science and Technology (FIST), State Key Laboratory of
Electrical Insulation and Power Equipment, MOE Key Laboratory for
Nonequilibrium Synthesis of Condensed Matter, Xi’an Key Laboratory
of Electronic Devices and Materials Chemistry and School of Chemistry, Xi’an Jiaotong University, 99 Yanxiang Road, Xi’an, Shaanxi 710054, P. R. China
| | - Gemma K. Gransbury
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | | | - Tomáš Hajdu
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Photon
Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Ilya Strashnov
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Eric J. L. McInnes
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Photon
Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Richard E. P. Winpenny
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Nicholas F. Chilton
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - David P. Mills
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Yan-Zhen Zheng
- Frontier
Institute of Science and Technology (FIST), State Key Laboratory of
Electrical Insulation and Power Equipment, MOE Key Laboratory for
Nonequilibrium Synthesis of Condensed Matter, Xi’an Key Laboratory
of Electronic Devices and Materials Chemistry and School of Chemistry, Xi’an Jiaotong University, 99 Yanxiang Road, Xi’an, Shaanxi 710054, P. R. China
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2
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Collins BK, Bhuvanesh N, Gladysz JA. A new supramolecular bonding motif involving NH bonds of ammonium salts and macrocycles derived from platinum corners and butadiynediyl linkers. Dalton Trans 2022; 51:16795-16799. [DOI: 10.1039/d2dt02680e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The title Pt4C16 species can give roughly planar geometries in crystals, but afford folded forms with ammonium cations, which are captured like unsuspecting prey and potentially fossilized as with the ancient creatures who once roamed the galaxy.
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Affiliation(s)
- Brenna K. Collins
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, USA
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, USA
| | - John A. Gladysz
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, USA
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3
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Kabadi EM, Khire SS, Pingale SS, Gadre SR, Chiba T, Fujji A. Theoretical and experimental study of IR spectra of large phenol-acetylene clusters, Ph(Ac)n for 8 ≤ n ≤ 12. J INDIAN CHEM SOC 2021. [DOI: 10.1016/j.jics.2021.100100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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4
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Tiwari N, Rai R, Sinha N. Water-lipid interactions in native bone by high-resolution solid-state NMR spectroscopy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 107:101666. [PMID: 32371298 DOI: 10.1016/j.ssnmr.2020.101666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
The study of structural and dynamical properties of lipid and its associated interaction with different components of bone is essential to understand its role at a different level of bone homeostasis such as bone mineralization and bone metabolism. In this article, we present water-dependent dynamical changes observed in lipids (triglycerides) in its absolute native environment inside bone by high-resolution 1H solid-state nuclear magnetic resonance spectroscopy (ssNMR). Relaxation measurement (T2 measurement) ssNMR experiments were performed at different levels of water network induced by dehydration and H/D exchange in native bone. Our measurements reflect the changes in the local environment and dynamical properties of triglyceride due to different hydration levels. The present study explains the role of water in stabilizing the structural properties of triglycerides in bone hence will help understand its pathological role associated with bone physiology and bone disorders.
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Affiliation(s)
- Nidhi Tiwari
- Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow, 226014, India; Department of Chemistry, Institute of Sciences, Banaras Hindu University, Varanasi, 221005, India
| | - RamaNand Rai
- Department of Chemistry, Institute of Sciences, Banaras Hindu University, Varanasi, 221005, India
| | - Neeraj Sinha
- Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow, 226014, India.
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5
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Nicholas HM, Vonci M, Goodwin CAP, Loo SW, Murphy SR, Cassim D, Winpenny REP, McInnes EJL, Chilton NF, Mills DP. Electronic structures of bent lanthanide(III) complexes with two N-donor ligands. Chem Sci 2019; 10:10493-10502. [PMID: 32110338 PMCID: PMC7020784 DOI: 10.1039/c9sc03431e] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/17/2019] [Indexed: 01/19/2023] Open
Abstract
Low coordinate metal complexes can exhibit superlative physicochemical properties, but this chemistry is challenging for the lanthanides (Ln) due to their tendency to maximize electrostatic contacts in predominantly ionic bonding regimes. Although a handful of Ln2+ complexes with only two monodentate ligands have been isolated, examples in the most common +3 oxidation state have remained elusive due to the greater electrostatic forces of Ln3+ ions. Here, we report bent Ln3+ complexes with two bis(silyl)amide ligands; in the solid state the Yb3+ analogue exhibits a crystal field similar to its three coordinate precursor rather than that expected for an axial system. This unanticipated finding is in opposition to the predicted electronic structure for two-coordinate systems, indicating that geometries can be more important than the Ln ion identity for dictating the magnetic ground states of low coordinate complexes; this is crucial transferable information for the construction of systems with enhanced magnetic properties.
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Affiliation(s)
- Hannah M Nicholas
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Michele Vonci
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Conrad A P Goodwin
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Song Wei Loo
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Siobhan R Murphy
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Daniel Cassim
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Richard E P Winpenny
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Eric J L McInnes
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Nicholas F Chilton
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - David P Mills
- Department of Chemistry , School of Natural Sciences , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
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6
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Carr PJJ, Warneke J, Featherstone J, Jenne C, Loire E, Hopkins WS. The structure of proton-bound Triethylammonia (X = F, Cl) Clusters. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1595203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
| | - Jonas Warneke
- Department of Chemistry, Purdue University, West Lafayette, USA
| | | | - Carsten Jenne
- Fakultät für Mathematik und Naturwissenschaften, Anorganische Chemie, Bergische Universität Wuppertal, Wuppertal, Germany
| | - Estelle Loire
- CLIO/LCP Bat. 201, Porte 2, Université Paris-Sud 11, Orsay, France
| | - W. Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo Canada
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7
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Liu J, Reta D, Cleghorn JA, Yeoh YX, Ortu F, Goodwin CAP, Chilton NF, Mills DP. Light Lanthanide Metallocenium Cations Exhibiting Weak Equatorial Anion Interactions. Chemistry 2019; 25:7749-7758. [PMID: 30994214 PMCID: PMC6637382 DOI: 10.1002/chem.201901167] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Indexed: 11/20/2022]
Abstract
As the dysprosocenium complex [Dy(Cpttt)2][B(C6F5)4] (Cpttt=C5H2tBu3‐1,2,4, 1‐Dy) exhibits magnetic hysteresis at 60 K, similar lanthanide (Ln) complexes have been targeted to provide insights into this remarkable property. We recently reported homologous [Ln(Cpttt)2][B(C6F5)4] (1‐Ln) for all the heavier Ln from Gd–Lu; herein, we extend this motif to the early Ln. We find, for the largest LnIII cations, that contact ion pairs [Ln(Cpttt)2{(C6F5‐κ1‐F)B(C6F5)3}] (1‐Ln; La–Nd) are isolated from reactions of parent [Ln(Cpttt)2(Cl)] (2‐Ln) with [H(SiEt3)2][B(C6F5)4], where the anion binds weakly to the equatorial sites of [Ln(Cpttt)2]+ through a single fluorine atom in the solid state. For smaller SmIII, [Sm(Cpttt)2][B(C6F5)4] (1‐Sm) is isolated, which like heavier 1‐Ln does not exhibit equatorial anion interactions, but the EuIII analogue 1‐Eu could not be synthesised due to the facile reduction of EuIII precursors to EuII products. Thus with the exception of Eu and radioactive Pm this work constitutes a structurally similar family of Ln metallocenium complexes, over 50 years after the [M(Cp)2]+ series was isolated for the 3d metals.
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Affiliation(s)
- Jingjing Liu
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Daniel Reta
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Jake A Cleghorn
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Yu Xuan Yeoh
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Fabrizio Ortu
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Conrad A P Goodwin
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Nicholas F Chilton
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - David P Mills
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
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8
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Carvalho LC, Bueno MA, de Oliveira BG. The interplay and strength of the π⋯HF, C⋯HF, F⋯HF and F⋯HC hydrogen bonds upon the formation of multimolecular complexes based on C 2H 2⋯HF and C 2H 4⋯HF small dimers. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 213:438-455. [PMID: 30738351 DOI: 10.1016/j.saa.2019.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/20/2018] [Accepted: 01/01/2019] [Indexed: 06/09/2023]
Abstract
The conception of this theoretical research was idealized aiming to unveil the intermolecular structures of complexes formed by acetylene or ethylene and hydrofluoric acid. At light of computational calculations by using the B3LYP/6-311++G(d,p) method, the geometries of the C2H2⋯(HF), C2H2⋯2(HF), C2H2⋯4(HF), C2H4⋯(HF), C2H4⋯2(HF) and C2H4⋯4(HF) hydrogen-bonded complexes were fully optimized. Moreover, the Post-Hartree-Fock calculations MP2/6-311++G(d,p), MP2/aug-cc-pVTZ, MP4(SDQ)/6-311++G(d,p) and CCSD/6-311++G(d,p) also were also used. The infrared spectra were analyzed in order to identify the new vibrational modes and frequencies of the proton donors shifted to red region. Through the modeling of charge-fluxes on the basis of the Quantum Theory of Atoms In Molecules (QTAIM) and, by contradicting the expectation of the hydrofluorination mechanisms of acetylene or ethylene, C⋯HF was recognized as a new type of hydrogen bond instead of the already well known π⋯H. The calculations of the Natural Bonding Orbital (NBO) and Charges derived from the Electrostatic Potential Grid-based (ChElPG) were also applied to interpret the shifting frequencies as well as measuring of the punctual charge-transfer after the formation of the complexes. Finally, the determination of the stabilization energy was carried out through the arguments of the Fock matrix in NBO basis and through the supermolecule approach. Also it is worthwhile to notice that some algebraic formulations were used for determining the electronic cooperative effect (CE).
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9
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Galabov B, Koleva G, Hadjieva B, Schaefer HF. π-Hydrogen Bonding Probes the Reactivity of Aromatic Compounds: Nitration of Substituted Benzenes. J Phys Chem A 2019; 123:1069-1076. [PMID: 30624929 DOI: 10.1021/acs.jpca.8b12508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The shifts of phenol O-H stretching vibration frequencies [Δν(OH)exp] upon π-hydrogen bonding with aromatic compounds is proposed as a spectroscopic probe of the reactivity of aromatic substrates toward electrophiles. A single infrared spectrum reflecting the Δν(OH)exp shift for an aromatic species in a reference solvent (CCl4 in this study) provides a good estimate of reactivity. The methodology is applied in rationalizing reactivity trends for the BF3 catalyzed nitration by methylnitrate in nitromethane of 20 aromatic reactants, including benzene, 11 methylbenzenes, several monoalkyl benzenes, the four halobenzenes, and anisole. Literature kinetic data are employed in the analysis. Very good correlations between relative rates of nitration and Δν(OH)exp are obtained. The approach is best applied to reactions, where the initial interactions between the reactants controls the rates. A new theoretical quantity, the shifts (with respect to benzene) of the molecular electrostatic potential at 1.5 Å over the centroid of the aromatic ring [Δ V(1.5)] is defined and shown to provide a good description of substituent effects on properties of the aromatic species. B3LYP density functional and MP2 ab initio methods combined with the 6-311++G(3df,2pd) basis set are employed in evaluating the Δ V(1.5) values.
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Affiliation(s)
- Boris Galabov
- Department of Chemistry and Pharmacy , University of Sofia , Sofia 1164 , Bulgaria
| | - Gergana Koleva
- Department of Chemistry and Pharmacy , University of Sofia , Sofia 1164 , Bulgaria
| | - Boriana Hadjieva
- Department of Chemistry and Pharmacy , University of Sofia , Sofia 1164 , Bulgaria
| | - Henry F Schaefer
- Center for Computational Quantum Chemistry , University of Georgia , Athens , Georgia 30602 , United States
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10
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Goodwin CAP, Reta D, Ortu F, Chilton NF, Mills DP. Synthesis and Electronic Structures of Heavy Lanthanide Metallocenium Cations. J Am Chem Soc 2017; 139:18714-18724. [DOI: 10.1021/jacs.7b11535] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Conrad A. P. Goodwin
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Daniel Reta
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Fabrizio Ortu
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Nicholas F. Chilton
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - David P. Mills
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
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11
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Goodwin CAP, Ortu F, Reta D, Chilton NF, Mills DP. Molecular magnetic hysteresis at 60 kelvin in dysprosocenium. Nature 2017; 548:439-442. [DOI: 10.1038/nature23447] [Citation(s) in RCA: 1161] [Impact Index Per Article: 165.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/27/2017] [Indexed: 01/20/2023]
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12
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Bolli C, Derendorf J, Jenne C, Keßler M. Halogenatedcloso-Dodecaborate Anions Stabilize Weakly Bound [(Me3NH)3X]2+(X = Cl, Br) Dications in the Solid State. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700620] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Christoph Bolli
- Fakultät für Mathematik und Naturwissenschaften; Anorganische Chemie; Bergische Universität Wuppertal; Gaussstr. 20 42119 Wuppertal Germany
| | - Janis Derendorf
- Fakultät für Mathematik und Naturwissenschaften; Anorganische Chemie; Bergische Universität Wuppertal; Gaussstr. 20 42119 Wuppertal Germany
| | - Carsten Jenne
- Fakultät für Mathematik und Naturwissenschaften; Anorganische Chemie; Bergische Universität Wuppertal; Gaussstr. 20 42119 Wuppertal Germany
| | - Mathias Keßler
- Fakultät für Mathematik und Naturwissenschaften; Anorganische Chemie; Bergische Universität Wuppertal; Gaussstr. 20 42119 Wuppertal Germany
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13
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Hasani M, Yarger JL, Angell CA. On the Use of a Protic Ionic Liquid with a Novel Cation To Study Anion Basicity. Chemistry 2016; 22:13312-9. [DOI: 10.1002/chem.201601428] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Mohammad Hasani
- School of Molecular Sciences; Arizona State University; Tempe Arizona 85287 USA
| | - Jeffery L. Yarger
- School of Molecular Sciences; Arizona State University; Tempe Arizona 85287 USA
| | - C. Austen Angell
- School of Molecular Sciences; Arizona State University; Tempe Arizona 85287 USA
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14
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Stoyanov ES, Gomes GDP. tert-Butyl Carbocation in Condensed Phases: Stabilization via Hyperconjugation, Polarization, and Hydrogen Bonding. J Phys Chem A 2015; 119:8619-29. [DOI: 10.1021/acs.jpca.5b04657] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Evgenii S. Stoyanov
- N. N. Vorozhtsov
Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of the Sciences (SB RAS), Novosibirsk 630090, Russia
- Department
of Natural Science, National Research University - Novosibirsk State University, Novosibirsk 630090, Russia
| | - Gabriel dos Passos Gomes
- Department
of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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15
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Jenne C, Keßler M, Warneke J. Protic anions [H(B12X12)]- (X = F, Cl, Br, I) that act as Brønsted acids in the gas phase. Chemistry 2015; 21:5887-91. [PMID: 25735766 DOI: 10.1002/chem.201500034] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Indexed: 11/07/2022]
Abstract
The acidity of protic cations and neutral molecules has been studied extensively in the gas phase, and the gas-phase acidity has been established previously as a very useful measure of the intrinsic acidity of neutral and cationic compounds. However, no data for any anionic acids were available prior to this study. The protic anions [H(B12X12)](-) (X = F, Cl, Br, I) are expected to be the most acidic anions known to date. Therefore, they were investigated in this study with respect to their ability to protonate neutral molecules in the gas phase by using a combination of mass spectrometry and quantum-chemical calculations. For the first time it was shown that in the gas phase protic anions are also able to protonate neutral molecules and thus act as Brønsted acids. According to theoretical calculations, [H(B12I12)](-) is the most acidic gas-phase anion, whereas in actual protonation experiments [H(B12Cl12)](-) is the most potent gas-phase acidic anion for the protonation of neutral molecules. This discrepancy is explained by ion pairing and kinetic effects.
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Affiliation(s)
- Carsten Jenne
- Fachbereich C, Anorganische Chemie, Bergische Universität Wuppertal, Gaussstrasse 20, 42119 Wuppertal (Germany).
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16
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Reed CA, Stoyanov ES, Tham FS. Hydrogen bonding versus hyperconjugation in condensed-phase carbocations. Org Biomol Chem 2014; 11:3797-802. [PMID: 23632995 DOI: 10.1039/c3ob40737c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hyperconjugative stabilization of positive charge in tertiary carbocations is the textbook explanation for their stability and low frequency νCH bands in their IR spectra have long been taken as confirming evidence. While this is substantiated in the gas phase by the very close match of the IR spectrum of argon-tagged t-butyl cation with that calculated under C(s) symmetry, the situation in condensed phases is much less clear. The congruence of νCH(max) of t-Bu(+) in superacid media (2830 cm(-1)) with that in the gas phase (2834 cm(-1)) has recently been shown to be accidental. Rather, νCH(max) varies considerably as a function of counterion in a manner that reveals the presence of significant C-H···anion hydrogen bonding. This paper addresses the question of the relative importance of hyperconjugation versus H-bonding. We show by assigning IR spectra in the νCH region to specific C-H bonds in t-butyl cation that the low frequency νCH(max) band in the IR spectrum of t-butyl cation, long taken as direct evidence for hyperconjugation, appears to be due mostly to H-bonding. The appearance of similar low frequency νCH bands in the IR spectra of secondary alkyl carboranes such as i-Pr(CHB11Cl11), which have predominant sp(3) centres rather than sp(2) centres (and are therefore less supportive of hyperconjugation), also suggests the dominance of H-bonding over hyperconjugation.
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Affiliation(s)
- Christopher A Reed
- Department of Chemistry, University of California, Riverside, California 92651, USA.
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17
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Mercadal N, Day SP, Jarmyn A, Pitak MB, Coles SJ, Wilson C, Rees GJ, Hanna JV, Wallis JD. O- vs. N-protonation of 1-dimethylaminonaphthalene-8-ketones: formation of a peri N–C bond or a hydrogen bond to the pi-electron density of a carbonyl group. CrystEngComm 2014. [DOI: 10.1039/c4ce00981a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Peri-amino-naphthylketones protonate on O or N forming a long peri-N–C bond or a hydrogen bond to the ketone's π-density.
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Affiliation(s)
- Nerea Mercadal
- School of Science and Technology
- Nottingham Trent University
- Clifton Lane
- Nottingham NG11 8NS, UK
| | - Stephen P. Day
- Department of Physics
- University of Warwick
- Coventry CV4 7AL, UK
| | - Andrew Jarmyn
- School of Science and Technology
- Nottingham Trent University
- Clifton Lane
- Nottingham NG11 8NS, UK
| | - Mateusz B. Pitak
- UK National Crystallography Service, Chemistry
- University of Southampton
- Highfield Campus
- Southampton, UK
| | - Simon J. Coles
- UK National Crystallography Service, Chemistry
- University of Southampton
- Highfield Campus
- Southampton, UK
| | - Claire Wilson
- Diamond Light Source Ltd
- Harwell Science and Innovation Campus
- Didcot, UK
| | - Gregory J. Rees
- Department of Physics
- University of Warwick
- Coventry CV4 7AL, UK
| | - John V. Hanna
- Department of Physics
- University of Warwick
- Coventry CV4 7AL, UK
| | - John D. Wallis
- School of Science and Technology
- Nottingham Trent University
- Clifton Lane
- Nottingham NG11 8NS, UK
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18
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Oliveira BGD. Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H−δ⋯H+δdihydrogen bonds. Phys Chem Chem Phys 2013; 15:37-79. [DOI: 10.1039/c2cp41749a] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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19
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Siu PW, Gates DP. HL2[P(1,2-O2C6H4)3] (L = DMSO or DMF): A Convenient Proton Source with a Weakly Basic Phosphorus(V) Anion. Organometallics 2009. [DOI: 10.1021/om9003187] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul W. Siu
- Department of Chemistry, University of British Columbia, Vancouver, 2036 Main Mall, British Columbia, Canada V6T 1Z1
| | - Derek P. Gates
- Department of Chemistry, University of British Columbia, Vancouver, 2036 Main Mall, British Columbia, Canada V6T 1Z1
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