1
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Saha A, Ganguly B. Exploiting the (-C-H···C-) Interaction to Design Cage-Functionalized Organic Superbases and Hyperbases: A Computational Study. ACS OMEGA 2023; 8:38546-38556. [PMID: 37867725 PMCID: PMC10586256 DOI: 10.1021/acsomega.3c05401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 09/22/2023] [Indexed: 10/24/2023]
Abstract
A set of carbon center-based P-ylidesubstituting bases have been exploited computationally with pentacyclo[5.4.0.02,6.03,10.05.9]undecane (PCU) and pentacyclo [6.4.0.02,7.03,11.06,10] dodecane (PCD) scaffolds using the B3LYP-D3/6-311+G(d,p) level of theory. The proton affinities calculated in the gas phase are in the range of superbases and hyperbases. The Atomsin-Molecules and Natural Bond Orbital calculations reveal that the -C-H···C- interaction plays a substantial role in improving the basicity, and tuning the -C-H···C- interaction can enhance the basicity of such systems. The free activation energy for proton exchange for PCD and PCU scaffolds substituted with P-ylide is substantially low. The computed results reveal the strength and nature of such - C-H···C- interactions compared to the -N-H···N- hydrogen bonds. The isodesmic reactions suggest that the superbasicity achieved using these frameworks arises from a combination of several factors, such as the ring strain of the bases in their unprotonated form, steric repulsion, and the intramolecular -C-H···C- interaction.
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Affiliation(s)
- Anusuya Saha
- Computation
and Simulation Unit, Analytical and Environmental Science Division
and Centralized Instrument Facility, CSIR-Central
Salt & Marine Chemicals Research Institute, Bhavnagar, Gujarat 364002, India
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Bishwajit Ganguly
- Computation
and Simulation Unit, Analytical and Environmental Science Division
and Centralized Instrument Facility, CSIR-Central
Salt & Marine Chemicals Research Institute, Bhavnagar, Gujarat 364002, India
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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2
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Aptekarev T, Furman G, Sokolovsky V, Panich A, Xia Y. Multicomponents of spin-spin relaxation, anisotropy of the echo decay, and nanoporous sample structure. RESEARCH SQUARE 2023:rs.3.rs-2893081. [PMID: 37214947 PMCID: PMC10197777 DOI: 10.21203/rs.3.rs-2893081/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have experimentally and theoretically investigated multicomponent 1H nuclear magnetic resonance (NMR) echo decays in a-Si:H films containing anisotropic nanopores, in which randomly moving hydrogen molecules are entrapped. The experimental results are interpreted within the framework of the previously developed theory, in which a nanoporous material is represented as a set of nanopores containing liquid or gas, and the relaxation rate is determined by the dipole-dipole spin interaction, considering the restricted motion of molecules inside the pores. Previously, such characteristics of a nanostructure as the average volume of pores and their orientation distribution were determined from the angular dependences of the spin-spin and spin-lattice relaxation times. We propose a new approach to the analysis of the NMR signal, the main advantage of which is the possibility of obtaining nanostructure parameters from a single decay of the echo signal. In this case, there is no need to analyze the anisotropy of the relaxation time T 2 , the determination of which is a rather complicated problem in multicomponent decays. Despite multicomponent signals, the fitting parameter associated with the size and shape of nanopores is determined quite accurately. This made it possible to determine the size and shape of nanopores in a-Si:H films, herewith our estimates are in good agreement with the results obtained by other methods. The fitting of the decays also provides information about the nanostructure of the sample, such as the standard deviations of the angular distribution of pores and the polar and azimuthal angles of the average direction of the pore axes relative to the sample axis, with reasonable accuracy. The approach makes it possible to quantitatively determine the parameters of the non-spherical nanoporous structure from NMR data in a non-destructive manner.
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Affiliation(s)
- Theodore Aptekarev
- Physics Department, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Gregory Furman
- Physics Department, Ben Gurion University of the Negev, Beer Sheva, Israel
| | | | - Alexander Panich
- Physics Department, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Yang Xia
- Physics Department, Oakland University, Rochester, MI, US
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3
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Stene RE, Graubner T, Ivlev SI, Karttunen AJ, Kraus F. A Symmetric F−H−F Hydrogen Bond in Strontium Bifluoride, Sr[HF
2
]
2. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202100374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Riane E. Stene
- Anorganische Chemie Fluorchemie Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Str.4 35032 Marburg Germany
| | - Tim Graubner
- Anorganische Chemie Fluorchemie Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Str.4 35032 Marburg Germany
| | - Sergei I. Ivlev
- Anorganische Chemie Fluorchemie Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Str.4 35032 Marburg Germany
| | - Antti J. Karttunen
- Department of Chemistry and Materials Science Aalto University Kemistintie 1 FI-02150 Espoo Finland
| | - Florian Kraus
- Anorganische Chemie Fluorchemie Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Str.4 35032 Marburg Germany
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4
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Gorinchoy N, Balan I, Polinger V, Bersuker I. Pseudo Jahn-Teller Origin of the Proton-transfer Energy Barrier in the Hydrogen-bonded [FHF]-System. CHEMISTRY JOURNAL OF MOLDOVA 2021. [DOI: 10.19261/cjm.2021.834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The results of ab initio calculations of the adiabatic potential energy surfaces for the proton-bound [FHF]- system at different F-F distances have been rationalized in the framework of the vibronic theory. It is shown that the instability of the symmetric D∞h structure at increased F∙∙∙F distances and the proton displacement to one of the fluorine atoms is due to the pseudo Jahn–Teller mixing of the ground 1Σg electronic state with the lowest excited state of 1Σu symmetry through the asymmetric σu vibrational mode.
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5
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Actual Symmetry of Symmetric Molecular Adducts in the Gas Phase, Solution and in the Solid State. Symmetry (Basel) 2021. [DOI: 10.3390/sym13050756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
This review discusses molecular adducts, whose composition allows a symmetric structure. Such adducts are popular model systems, as they are useful for analyzing the effect of structure on the property selected for study since they allow one to reduce the number of parameters. The main objectives of this discussion are to evaluate the influence of the surroundings on the symmetry of these adducts, steric hindrances within the adducts, competition between different noncovalent interactions responsible for stabilizing the adducts, and experimental methods that can be used to study the symmetry at different time scales. This review considers the following central binding units: hydrogen (proton), halogen (anion), metal (cation), water (hydrogen peroxide).
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6
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Tupikina EY, Denisov GS, Tolstoy PM. Anticooperativity of FH···Cl
−
hydrogen bonds in [FH)
n
Cl]
−
clusters (
n
= 1…6). J Comput Chem 2019; 40:2858-2867. [DOI: 10.1002/jcc.26066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/19/2019] [Accepted: 08/22/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Elena Yu. Tupikina
- Institute of ChemistrySt. Petersburg State University, Universitetsky pr. 26, 198504 Russia
- Department of PhysicsSt. Petersburg State University Uljanovskaja 1 St. Petersburg 198504 Russia
| | - Gleb S. Denisov
- Department of PhysicsSt. Petersburg State University Uljanovskaja 1 St. Petersburg 198504 Russia
| | - Peter M. Tolstoy
- Institute of ChemistrySt. Petersburg State University, Universitetsky pr. 26, 198504 Russia
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7
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Ivlev SI, Soltner T, Karttunen AJ, Mühlbauer MJ, Kornath AJ, Kraus F. Syntheses and Crystal Structures of Sodium Hydrogen Fluorides NaF·nHF (n= 2, 3, 4). Z Anorg Allg Chem 2017. [DOI: 10.1002/zaac.201700228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sergei I. Ivlev
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Straße 35032 Marburg Germany
| | - Theresa Soltner
- Department Chemie; Ludwig-Maximilians-Universität München; 81377 München Germany
| | - Antti J. Karttunen
- Department of Chemistry and Materials Science; Aalto University; 00076 Aalto Finland
| | - Martin J. Mühlbauer
- Heinz Maier-Leibnitz Zentrum (MLZ); Technische Universität München; Lichtenbergstraße 1 85747 Garching Germany
| | - Andreas J. Kornath
- Department Chemie; Ludwig-Maximilians-Universität München; 81377 München Germany
| | - Florian Kraus
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Straße 35032 Marburg Germany
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8
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Pylaeva SA, Elgabarty H, Sebastiani D, Tolstoy PM. Symmetry and dynamics of FHF− anion in vacuum, in CD2Cl2 and in CCl4. Ab initio MD study of fluctuating solvent–solute hydrogen and halogen bonds. Phys Chem Chem Phys 2017; 19:26107-26120. [DOI: 10.1039/c7cp04493c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Asymmetric solvation of FHF− by halogen- and hydrogen-bonding solvents breaks the symmetry of the anion.
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Affiliation(s)
- S. A. Pylaeva
- Institute of Chemistry, Martin-Luther Universität Halle-Wittenberg
- Germany
| | - H. Elgabarty
- Institute of Chemistry, Martin-Luther Universität Halle-Wittenberg
- Germany
| | - D. Sebastiani
- Institute of Chemistry, Martin-Luther Universität Halle-Wittenberg
- Germany
| | - P. M. Tolstoy
- Center for Magnetic Resonance, St. Petersburg State University
- Russia
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9
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Shimizu K, Driver GW, Lucas M, Sparrman T, Shchukarev A, Boily JF. Bifluoride ([HF2]−) formation at the fluoridated aluminium hydroxide/water interface. Dalton Trans 2016; 45:9045-50. [DOI: 10.1039/c5dt04425a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Bifluoride-type species are formed at fluoride-exchanged aluminium hydroxide surfaces contacted with aqueous solutions. First layer surface species are anchors for growth of multi-layered species towards the solution.
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Affiliation(s)
- Kenichi Shimizu
- Department of Chemistry
- Umeå University
- SE-901 87 Umeå, Sweden
- Physical and Theoretical Chemistry Laboratory
- Department of Chemistry
| | | | - Marie Lucas
- Department of Chemistry
- Umeå University
- SE-901 87 Umeå, Sweden
| | - Tobias Sparrman
- Department of Chemistry
- Umeå University
- SE-901 87 Umeå, Sweden
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10
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[FHF]−—The Strongest Hydrogen Bond under the Influence of External Interactions. CRYSTALS 2015. [DOI: 10.3390/cryst6010003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Gonzalo EC, Sanjuán ML, Hoelzel M, Azcondo MT, Amador U, Sobrados I, Sanz J, García-Alvarado F, Kuhn A. Synthesis and characterization of NaNiF3·3H2O: an unusual ordered variant of the ReO3 type. Inorg Chem 2015; 54:3172-82. [PMID: 25790238 DOI: 10.1021/ic5026262] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new hydrated sodium nickel fluoride with nominal composition NaNiF3·3H2O was synthesized using an aqueous solution route. Its structure was solved by means of ab initio methods from powder X-ray diffraction and neutron diffraction data. NaNiF3·3H2O crystallizes in the cubic crystal system, space group Pn3̅ with a = 7.91968(4) Å. The framework, derived from the ReO3 structure type, is built from NaX6 and NiX6 (X = O, F) corner-shared octahedra, in which F and O atoms are randomly distributed on a single anion site. The 2a × 2a × 2a superstructure arises from the strict alternate three-dimensional linking of NaX6 and NiX6 octahedra together with the simultaneous tilts of the octahedra from the cube axis (φ = 31.1°), with a significant participation of hydrogen bonding. NaNiF3·3H2O corresponds to a fully cation-ordered variant of the In(OH)3 structure, easily recognizable when formulated as NaNi(XH)6 (X = O, F). It constitutes one of the rare examples for the a(+)a(+)a(+) tilting scheme with 1:1 cation ordering in perovskite-related compounds. The Curie-like magnetic behavior well-reflects the isolated paramagnetic Ni(2+) centers without worth mentioning interactions. While X-ray and neutron diffraction data evidence Na/Ni order in combination with O/F disorder as a main feature of this fluoride, results from Raman and magic-angle spinning NMR spectroscopies support the existence of specific anion arrangements in isolated square windows identified in structural refinements. In particular, formation of water molecules derives from unfavorable FH bond formation.
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Affiliation(s)
- Elena C Gonzalo
- †Facultad de Farmacia, Departamento de Química y Bioquímica, Universidad CEU San Pablo, Urbanización Montepríncipe, 28668 Boadilla del Monte, Madrid, Spain
| | - María Luisa Sanjuán
- ‡Facultad de Ciencias, Instituto de Ciencia de Materiales de Aragón (Universidad de Zaragoza-CSIC), 50009 Zaragoza, Spain
| | - Markus Hoelzel
- §Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, D-85747 Garching, Germany
| | - M Teresa Azcondo
- †Facultad de Farmacia, Departamento de Química y Bioquímica, Universidad CEU San Pablo, Urbanización Montepríncipe, 28668 Boadilla del Monte, Madrid, Spain
| | - Ulises Amador
- †Facultad de Farmacia, Departamento de Química y Bioquímica, Universidad CEU San Pablo, Urbanización Montepríncipe, 28668 Boadilla del Monte, Madrid, Spain
| | - Isabel Sobrados
- ∥Instituto de Ciencia de Materiales de Madrid, CSIC, 28006 Madrid, Spain
| | - Jesús Sanz
- ∥Instituto de Ciencia de Materiales de Madrid, CSIC, 28006 Madrid, Spain
| | - Flaviano García-Alvarado
- †Facultad de Farmacia, Departamento de Química y Bioquímica, Universidad CEU San Pablo, Urbanización Montepríncipe, 28668 Boadilla del Monte, Madrid, Spain
| | - Alois Kuhn
- †Facultad de Farmacia, Departamento de Química y Bioquímica, Universidad CEU San Pablo, Urbanización Montepríncipe, 28668 Boadilla del Monte, Madrid, Spain
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12
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Shvartsev B, Gelman D, Komissarov I, Epshtein A, Starosvetsky D, Ein-Eli Y. Influence of Solution Volume on the Dissolution Rate of Silicon Dioxide in Hydrofluoric Acid. Chemphyschem 2014; 16:370-6. [DOI: 10.1002/cphc.201402627] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Indexed: 11/06/2022]
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13
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Pérez-Hernández G, González-Vázquez J, González L. IR Spectrum of FHF– and FDF– Revisited Using a Spectral Method in Four Dimensions. J Phys Chem A 2012; 116:11361-9. [DOI: 10.1021/jp3058383] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Leticia González
- Institute of Theoretical Chemistry, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
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14
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Kong S, Borissova AO, Lesnichin SB, Hartl M, Daemen LL, Eckert J, Antipin MY, Shenderovich IG. Geometry and spectral properties of the protonated homodimer of pyridine in the liquid and solid states. A combined NMR, X-ray diffraction and inelastic neutron scattering study. J Phys Chem A 2011; 115:8041-8. [PMID: 21644583 DOI: 10.1021/jp203543g] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structure and spectral signatures of the protonated homodimer of pyridine in its complex with a poorly coordinating anion have been studied in solution in CDF(3)/CDClF(2) down to 120 K and in a single crystal. In both phases, the hydrogen bond is asymmetric. In the solution, the proton is involved in a fast reversible transfer that determines the multiplicity of NMR signals and the sign of the primary H/D isotope effect of --0.95 ppm. The proton resonates at 21.73 ppm that is above any value reported in the past and is indicative of a very short hydrogen bond. By combining X-ray diffraction analysis with model computations, the position of the proton in the crystal has been defined as d(N-H) = 1.123 Å and d(H···N) = 1.532 Å. The same distances have been estimated using a (15)N NMR correlation. The frequency of the protonic out-of-plane bending mode is 822 cm(-1) in agreement with Novak's correlation.
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Affiliation(s)
- S Kong
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
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15
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Affiliation(s)
- Sławomir Janusz Grabowski
- Kimika Fakultatea, Euskal Herriko Unibertsitatea and Donostia International Physics Center (DIPC) P.K. 1072, 20080 Donostia, Euskadi, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
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16
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Shenderovich IG, Smirnov SN, Denisov GS, Gindin VA, Golubev NS, Dunger A, Reibke R, Kirpekar S, Malkina OL, Limbach HH. Nuclear magnetic resonance of hydrogen bonded clusters between F− and (HF)n: Experiment and theory. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19981020322] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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18
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Becker C, Kieltsch I, Broggini D, Mezzetti A. Bridging Fluorides and Hard/Soft Mismatch in d6 and d8 Complexes: The Case of [Tl(μ-F)3Ru(PPh3)3]. Inorg Chem 2003; 42:8417-29. [PMID: 14658895 DOI: 10.1021/ic034888e] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[RuCl2(PPh3)3] reacts with thallium(I) fluoride to give either [Tl(mu-F)3Ru(PPh3)3] (1) or [Tl(mu3-F)(mu2-Cl)2Ru2(mu2-Cl)(mu2-F)(PPh3)4] (2) depending on the excess of TlF used. Both 1 and 2 were fully characterized, including X-ray structure determinations. Complex 1 reacts with dihydrogen to form the known ruthenium hydride complex [Ru(H)2(H2)(PPh3)3] upon hydrogenolysis of the Ru-F bond. The reaction of 1 with activated alkyl bromides (R-Br) gives the corresponding alkyl fluorides and the trinuclear complex [Tl(mu3-F)(mu2-F)(mu2-X)Ru2(mu2-Br)(mu2-F)(PPh3)4] (X=Br, F) (3), whose structure closely resembles that of 2. However, 1 is not active as catalyst for the nucleophilic fluorination of R-Br in the presence of thallium fluoride. The effect of the bridging coordination mode of fluoride on the Ru-F bond is discussed in terms of the HSAB principle, which suggests a more general model for predicting the stability of d6 and d8 complexes containing hard ligands (such as fluoro, oxo, and amido).
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Affiliation(s)
- Claus Becker
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, ETH Hönggerberg, CH-8093 Zürich, Switzerland
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19
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Khaikin L, Grikina O, Vilkov L, Golubinskii A, Atavin E, Asfin R, Denisov G. Gas-phase electron diffraction study of cyclic dimer of dimethylphosphinic acid (Me2P(O)OH)2 using quantum chemical data and a priori force field. J Mol Struct 2003. [DOI: 10.1016/s0022-2860(03)00289-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Dutta SK, Samanta S, Ghosh D, Butcher RJ, Chaudhury M. Oxovanadium(V) and cobalt(III) complexes of dithiocarbazate-based Schiff base ligands: formation of a thiadiazole ring by vanadium-induced cyclization of the coordinated ligand. Inorg Chem 2002; 41:5555-60. [PMID: 12377053 DOI: 10.1021/ic0200895] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
S-Methyl 3-((2-hydroxyphenyl)methyl)dithiocarbazate (H(2)L(1)) and its bromo derivative (H(2)L(2)), which are traditionally biprotic tridentate (ONS) ligands, behave in an unprecedented manner when allowed to react with [VO(acac)(2)] under an oxidative environment in acetonitrile-water medium containing a catalytic amount of alkali metal ion. The products obtained are oxovanadium(V) compounds [VOL(L(cyclic))] (L = L(1), 1a, and L(2), 1b) that contain one molecule of ligand which undergoes metal-induced cyclization to form a thiadiazole ring. Compound 1a crystallizes in the triclinic space group P(-)1 with a = 9.1830(9) A, b = 9.4165(12) A, c = 12.700(2) A, alpha = 100.988(8)(o), beta = 100.195(7)(o), gamma = 78.774(8)(o), V = 1046.3(2) A(3), and Z = 2. With cobalt(III), however, the products [CoL(HL)].H(2)O (L = L(1), 2a, and L(2), 2b) have hydrogen-bonded dimeric structures with each ligand virtually carrying 1.5 units of negative charge as confirmed by X-ray crystal structure analysis of 2a. It also crystallizes in triclinic space group P(-)1 with a = 12.0842(8) A, b = 13.5251(9) A, c = 14.1960(10) A, alpha = 78.122(6)(o), beta = 73.888(6)(o), gamma = 78.255(6)(o), V = 2154.7(3) A(3), and Z = 4. In solution, 2a is a symmetric molecule as indicated by (1)H NMR, involving a characteristic hydrogen-bonded O-H-O broad feature in the downfield (at 14.5 ppm) connecting both monoprotonated (LH(-)) and deprotonated (L(2-)) forms of the ligand--a situation somewhat analogous to the classic H-F-H case as observed in bifluoride ion.
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Affiliation(s)
- Subodh Kanti Dutta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
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