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Martins FA, de Azevedo Santos L, Rodrigues Silva D, Fonseca Guerra C, Bickelhaupt FM, Freitas MP. Iodine Gauche Effect Induced by an Intramolecular Hydrogen Bond. J Org Chem 2022; 87:11625-11633. [PMID: 35984736 DOI: 10.1021/acs.joc.2c01258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The gauche conformer in 1-X,2-Y-disubstituted ethanes, that is, the staggered orientation in which X and Y are in closer contact, is only favored for relatively small substituents that do not give rise to large X···Y steric repulsion. For more diffuse substituents, weakly attractive orbital interactions between antiperiplanar bonds (i.e., hyperconjugation) cannot overrule the repulsive forces between X and Y. Our quantum chemical analyses of the rotational isomerism of XCH2CH2Y (X = F, OH; Y = I) at ZORA-BP86-D3(BJ)/QZ4P reveal that indeed the anti conformer is generally favored due to a less destabilizing I···F and I···O-H steric repulsion. The only case when the gauche conformer is preferred is when the hydroxyl hydrogen is oriented toward the iodine atom in the 2-iodoethanol. This is because of the significantly stabilizing covalent component of the I···H-O intramolecular hydrogen bond. Therefore, we show that strong intramolecular interactions can overcome the steric repulsion between bulky substituents in 1,2-disubstituted ethanes and cause the gauche effect. Our quantum chemical computations have guided nuclear magnetic resonance experiments that confirm the increase in the gauche population as X goes from F to OH.
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Affiliation(s)
- Francisco A Martins
- Department of Chemistry, Institute of Natural Sciences, Federal University of Lavras, 37200-900 Lavras, Minas Gerais, Brazil
| | - Lucas de Azevedo Santos
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Daniela Rodrigues Silva
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Célia Fonseca Guerra
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - F Matthias Bickelhaupt
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.,Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Matheus P Freitas
- Department of Chemistry, Institute of Natural Sciences, Federal University of Lavras, 37200-900 Lavras, Minas Gerais, Brazil
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Moloto BP, Vermeeren P, Dalla Tiezza M, Esterhuysen C, Bickelhaupt FM, Hamlin TA. Palladium‐Catalyzed Activation of Carbon–Halogen Bonds: Electrostatics‐Controlled Reactivity. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | | | | | | | - Trevor A. Hamlin
- Vrije Universiteit Amsterdam Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling De Boelelaan 1083 1081 HV Amsterdam NETHERLANDS
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Martins FA, Chagas P, Thomasi SS, Oliveira LCA, Diniz R, Freitas MP. Theoretical and X-ray evidence of electrostatic phosphonium anti and gauche effects. Chemphyschem 2022; 23:e202100856. [PMID: 34995018 DOI: 10.1002/cphc.202100856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/21/2021] [Indexed: 11/12/2022]
Abstract
Sulfur, not phosphorus, is the only known third-row element capable of experiencing an electrostatic gauche effect with fluorine. Some six-membered rings containing an endocyclic phosphorus atom and a β-fluorine substituent that can interconvert to axial ( gauche relative to phosphorus) and equatorial positions were then analysed. While phosphines do not establish an electrostatic attraction between fluorine and phosphorus, some oxidised forms exhibit surprising stability for the sterically disfavoured axial orientation. Because the nature of this behaviour was not obvious, since an intramolecular hydrogen bond can appear, a phosphonium derivative was further studied and its axial conformation was found to be highly stable. A preference for the gauche arrangement appears even for the acyclic and sterically hindered (2-fluoroethyl)triphenylphosphonium cation. On the other hand, (ethane-1,2-diyl)bis(phosphonium) cations are exclusively in anti conformation due to an (+/+)-electrostatic repulsion between the positively charged phosphonium groups.
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Affiliation(s)
- Francisco A Martins
- Federal University of Lavras: Universidade Federal de Lavras, Chemistry, Av. Lagoa Azul, Casa, Lavras, 37200-900, Lavras, BRAZIL
| | | | - Sérgio S Thomasi
- Federal University of Lavras: Universidade Federal de Lavras, Chemistry, BRAZIL
| | | | - Renata Diniz
- Universidade Federal de Minas Gerais, Chemistry, BRAZIL
| | - Matheus P Freitas
- Federal University of Lavras, Department of Chemsitry, Campus UFLA, CP 3037, 37200-000, Lavras, BRAZIL
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de Azevedo Santos L, Cesario D, Vermeeren P, van der Lubbe SCC, Nunzi F, Fonseca Guerra C. σ-Electrons Responsible for Cooperativity and Ring Equalization in Hydrogen-Bonded Supramolecular Polymers. Chempluschem 2021; 87:e202100436. [PMID: 34709769 DOI: 10.1002/cplu.202100436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/18/2021] [Indexed: 11/08/2022]
Abstract
We have quantum chemically analyzed the cooperative effects and structural deformations of hydrogen-bonded urea, deltamide, and squaramide linear chains using dispersion-corrected density functional theory at BLYP-D3(BJ)/TZ2P level of theory. Our purpose is twofold: (i) reveal the bonding mechanism of the studied systems that lead to their self-assembly in linear chains; and (ii) rationalize the C-C bond equalization in the ring moieties of deltamide and squaramide upon polymerization. Our energy decomposition and Kohn-Sham molecular orbital analyses reveal cooperativity in all studied systems, stemming from the charge separation within the σ-electronic system by charge transfer from the carbonyl oxygen lone pair donor orbital of one monomer towards the σ* N-H antibonding acceptor orbital of the neighboring monomer. This key orbital interaction causes the C=O bonds to elongate, which, in turn, results in the contraction of the adjacent C-C single bonds that, ultimately, makes the ring moieties of deltamide and squaramide to become more regular. Notably, the π-electron delocalization plays a much smaller role in the total interaction between the monomers in the chain.
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Affiliation(s)
- Lucas de Azevedo Santos
- Department of Theoretical Chemistry, Amsterdam Institute for Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081, HV Amsterdam, The Netherlands
| | - Diego Cesario
- Department of Theoretical Chemistry, Amsterdam Institute for Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081, HV Amsterdam, The Netherlands
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, I-06123, Perugia, Italy
| | - Pascal Vermeeren
- Department of Theoretical Chemistry, Amsterdam Institute for Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081, HV Amsterdam, The Netherlands
| | - Stephanie C C van der Lubbe
- Department of Theoretical Chemistry, Amsterdam Institute for Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081, HV Amsterdam, The Netherlands
| | - Francesca Nunzi
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, I-06123, Perugia, Italy
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), Via Elce di Sotto 8, 06123, Perugia, Italy
| | - Célia Fonseca Guerra
- Department of Theoretical Chemistry, Amsterdam Institute for Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081, HV Amsterdam, The Netherlands
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333, CC Leiden, The Netherlands
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