DOCSLIB.ORG

A Study of Proposed Intermediates in the Deoxofluorination of Carbonyl Groups by Sf4

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Study of Proposed Intermediates in the Deoxofluorination of Carbonyl Groups by Sf4 A STUDY OF PROPOSED INTERMEDIATES IN THE DEOXOFLUORINATION OF CARBONYL GROUPS BY SF4 DANIEL STUART Honours Bachelor of Science, McMaster University, 2015 A Thesis Submitted to the School of Graduate Studies of the University of Lethbridge in Partial Fulfilment of the Requirements for the Degree MASTER OF SCIENCE Department of Chemistry and Biochemistry University of Lethbridge LETHBRIDGE, ALBERTA, CANADA © Daniel Stuart, 2018 A STUDY OF PROPOSED INTERMEDIATES IN THE DEOXOFLUORINATION OF CARBONYL GROUPS BY SF4 DANIEL STUART Date of Defence: May 16th, 2018 Dr. M. Gerken Professor Ph.D. Supervisor Dr. P. W. Dibble Associate Professor Ph.D. Thesis Examination Committee Member Dr. P. Hazendonk Associate Professor Ph.D. Thesis Examination Committee Member Dr. J. Müller Professor Ph.D. External Examiner University of Saskatchewan Saskatoon, Saskatchewan Dr. P. G. Hayes Professor Ph.D. Chair, Thesis Examination Committee Abstract The [SF4·O=C(CH3)2]2 and SF4·[O=C(CH3)2]2 adducts were synthesized and characterized at low temperature (LT) using Raman spectroscopy and, in the case of [SF4·O=C(CH3)2]2, single-crystal X-ray diffraction. The X-ray crystal structure of SF4·(O=C10H14)·(HF) was obtained, showing F4S---F−H---O=C10H14 interactions. + Adducts of [SF3] with acetone, cyclopentanone, and 2-adamantanone were shown by 19F and 1H NMR spectroscopy to exist in solutions below −40 °C. The proposed + [SF3·{O=C(CH3)2}3] cation was observed at LT by reacting [SF3][AsF6] with excess acetone. Above −40 °C SF4 formation was observed. + Protonated ketones, [HO=R] (R = C(CH3)2, C5H8, C10H14), and aldehydes, + + [H(O=CHC6H5)2] and [H(O=CHCH3)x] (x = 1 or 2), were isolated and characterized in the solid state for the first time. NBO analyses were used to quantify the increase in electrophilicity of the oxonium cations. The AsF5·O=R (R = C(CH3)2, C5H8, C10H14) adducts were synthesized and characterized in solution and solid state using LT NMR and Raman spectroscopies, respectively. iii Acknowledgments I would like to thank my supervisor, Dr. Michael Gerken, for his mentorship during my time in his research group. His patience, enthusiasm, and immense knowledge in the field of fluorine chemistry make him an excellent supervisor and inspired me to become a better chemist. Thank you for providing me with the opportunity to work in your lab. I would like to thank my committee members, Dr. Peter Dibble and Dr. Paul Hazendonk, for their encouragement and insightful comments over the course of my graduate studies. I would like to thank Dr. Jens Müller for taking time out of his busy schedule to review my thesis and travel to Lethbridge for my defence. Sincere thank-you goes out to Dr. Stacey D. Wetmore for providing me with the computational resources throughout this thesis, as well as her guidance during the preparation and submission of our published manuscript. I would also like to thank Dr. René T. Boeré for doing an excellent job in teaching me the basics of X-ray crystallography during his course. Thank you to the members of the Gerken group, Nathan Kostiuk and Douglas Turnbull, for their friendship, assistance in the lab, and many entertaining conversations. A special thanks to Nathan for helping settle into Lethbridge and introducing me to many new friends. I am also thankful for my fellow graduate student peers, Connor and Jackson, for all the amazing days skiing in the mountains. A heartfelt thanks to all the friends I made throughout the past few years, especially Kathleen, Katelyn, and Chris who have made my time in Lethbridge extra special. iv Finally, I would like to thank my family for their endless encouragement, constant love, and support. I am especially thankful for my parents, Pat and Mike, who are the reason I am where I am today. You are always there for me and I am eternally grateful. v Table of Contents 1. Introduction .................................................................................................................... 1 1.1 Organofluorine Chemistry ........................................................................................ 1 1.1.1 Deoxofluorination Reactions ............................................................................ 4 1.2 Sulfur Tetrafluoride ................................................................................................ 13 1.2.1 Adducts of SF4 and Organic Nitrogen and Oxygen Bases ............................. 14 + 1.3 The Chemistry of [SF3] ......................................................................................... 17 + 1.3.1 [SF3] ·Nitrogen-Base Adducts ........................................................................ 19 1.4 Goals of Present Research ...................................................................................... 21 2. Experimental ................................................................................................................ 27 2.1 General Methods ..................................................................................................... 27 2.2 Preparation and Purification of Starting Materials ................................................. 31 2.2.1 Sources and Purification of N2 and F2 ............................................................ 31 2.2.2 Solvent Purification; Anhydrous HF (aHF), SO2, CH2Cl2, and CFCl3 ........... 32 2.2.3 Purification of Oxygen-Bases ......................................................................... 34 2.2.4 Synthesis and Purification of SF4, SbF3 and AsF5 .......................................... 34 2.2.5 Synthesis of [SF3][AsF6] ................................................................................. 35 2.3 Reactions of SF4 with Ketones ............................................................................... 35 2.3.1 Reaction of SF4 with 2-Adamantanone ........................................................... 35 2.3.2 Reactions of SF4 with Acetone ....................................................................... 36 2.3.2.1 Reactions of SF4 with One Equivalent of Acetone ............................. 36 2.3.2.2 Reactions of SF4 with Two Equivalents of Acetone ........................... 37 2.4 Reactions of [SF3][AsF6] with Ketones in SO2 ....................................................... 37 2.4.1 Reaction of [SF3][AsF6] with Acetone ........................................................... 38 2.4.1.1 Reaction of [SF3][AsF6] with Excess Acetone .................................... 38 2.4.1.2 Reaction of [SF3][AsF6] with Three Equivalents of Acetone ............. 38 2.4.1.3 Reaction of [SF3][AsF6] with Three Equivalents of Acetone ............. 39 2.4.1.4 Reaction of [SF3][AsF6] with One Equivalent of Acetone .................. 39 2.4.2 Reaction of [SF3][AsF6] with Cyclopentanone ............................................... 40 2.4.2.1 Reaction of [SF3][AsF6] with Two Equivalents of Cyclopentanone ... 40 2.4.2.2 Reaction of [SF3][AsF6] with One Equivalent of Cyclopentanone ..... 41 2.4.3 Reaction of [SF3][AsF6] with 2-Adamantanone ............................................. 41 2.4.3.1 Reaction of [SF3][AsF6] with Two Equivalents of 2-Adamantanone ............................................................................. 41 2.4.3.2 Reaction of [SF3][AsF6] with One Equivalent of 2-Adamantanone ............................................................................. 42 2.5 Synthesis of Protonated Ketones ............................................................................ 43 2.5.1 Synthesis of [HO=C10H14][AsF6] .................................................................... 43 2.5.2 Synthesis of [HO=C10H14][SbF6] .................................................................... 44 vi 2.5.3 Synthesis of [HO=C5H8][AsF6] ...................................................................... 45 2.5.4 Synthesis of [HO=C5H8][SbF6]....................................................................... 45 2.5.5 Synthesis of [HO=C(CH3)2][SbF6] ................................................................. 46 2.5.6 Synthesis of [H{O=C(CH3)2}2]3[HO=C(CH3)2]3[SbF6]5F.............................. 46 2.6 Synthesis of Protonated Aldehydes ........................................................................ 47 2.6.1 Synthesis of [H(O=CHC6H5)2][SbF6] ............................................................. 47 2.6.2 Synthesis of [H(O=CHCH3)2][SbF6] and [HO=CHCH3][SbF6] ..................... 48 2.7 Synthesis of the Adducts of AsF5 with Ketones ..................................................... 49 2.7.1 Synthesis of AsF5·O=C(CH3)2 ........................................................................ 49 2.7.2 Synthesis of AsF5·O=C5H8 ............................................................................. 50 2.7.3 Synthesis of AsF5·O=C10H14........................................................................... 50 2.8 Single-Crystal X-ray Diffraction ............................................................................ 51 2.8.1 Low-Temperature Crystal Mounting .............................................................. 51 2.8.2 Data Collection and Reduction ....................................................................... 52 2.8.3 Structure Solution and Refinement ................................................................. 53 2.9 Raman Spectroscopy ............................................................................................... 54 2.10 NMR Spectroscopy ..............................................................................................
Load more

Recommended publications
  • Noncovalent Bonds Through Sigma and Pi-Hole Located on the Same Molecule. Guiding Principles and Comparisons
    molecules Review Noncovalent Bonds through Sigma and Pi-Hole Located on the Same Molecule. Guiding Principles and Comparisons Wiktor Zierkiewicz 1,* , Mariusz Michalczyk 1,* and Steve Scheiner 2 1 Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeze˙ Wyspia´nskiego27, 50-370 Wrocław, Poland 2 Department of Chemistry and Biochemistry, Utah State University Logan, Logan, UT 84322-0300, USA; [email protected] * Correspondence: [email protected] (W.Z.); [email protected] (M.M.) Abstract: Over the last years, scientific interest in noncovalent interactions based on the presence of electron-depleted regions called σ-holes or π-holes has markedly accelerated. Their high directionality and strength, comparable to hydrogen bonds, has been documented in many fields of modern chemistry. The current review gathers and digests recent results concerning these bonds, with a focus on those systems where both σ and π-holes are present on the same molecule. The underlying principles guiding the bonding in both sorts of interactions are discussed, and the trends that emerge from recent work offer a guide as to how one might design systems that allow multiple noncovalent bonds to occur simultaneously, or that prefer one bond type over another. Keywords: molecular electrostatic potential; halogen bond; pnicogen bond; tetrel bond; chalcogen bond; cooperativity Citation: Zierkiewicz, W.; Michalczyk, M.; Scheiner, S. Noncovalent Bonds through Sigma and Pi-Hole Located on the Same 1. Introduction Molecule. Guiding Principles and The concept of the σ-hole, introduced to a wide audience in 2005 at a conference in Comparisons. Molecules 2021, 26, Prague by Tim Clark [1], influenced a way of thinking about noncovalent interactions 1740.
    [Show full text]
  • The Hydrogen Bond: a Hundred Years and Counting
    J. Indian Inst. Sci. A Multidisciplinary Reviews Journal ISSN: 0970-4140 Coden-JIISAD © Indian Institute of Science 2019. The Hydrogen Bond: A Hundred Years and Counting Steve Scheiner* REVIEW REVIEW ARTICLE Abstract | Since its original inception, a great deal has been learned about the nature, properties, and applications of the H-bond. This review summarizes some of the unexpected paths that inquiry into this phenom- enon has taken researchers. The transfer of the bridging proton from one molecule to another can occur not only in the ground electronic state, but also in various excited states. Study of the latter process has devel- oped insights into the relationships between the nature of the state, the strength of the H-bond, and the height of the transfer barrier. The enormous broadening of the range of atoms that can act as both pro- ton donor and acceptor has led to the concept of the CH O HB, whose ··· properties are of immense importance in biomolecular structure and function. The idea that the central bridging proton can be replaced by any of various electronegative atoms has fostered the rapidly growing exploration of related noncovalent bonds that include halogen, chalco- gen, pnicogen, and tetrel bonds. Keywords: Halogen bond, Chalcogen bond, Pnicogen bond, Tetrel bond, Excited-state proton transfer, CH O H-bond ··· 1 Introduction charge on the proton. The latter can thus attract Over the course of its century of study following the partial negative charge of an approaching its earliest conceptual formulation1,2, the hydro- nucleophile D. Another important factor resides gen bond (HB) has surrendered many of the in the perturbation of the electronic structure mysteries of its source of stability and its myriad of the two species as they approach one another.
    [Show full text]
  • Chemical Physics 524 (2019) 55–62
    Chemical Physics 524 (2019) 55–62 Contents lists available at ScienceDirect Chemical Physics journal homepage: www.elsevier.com/locate/chemphys Structures of clusters surrounding ions stabilized by hydrogen, halogen, T chalcogen, and pnicogen bonds ⁎ ⁎ Steve Scheinera, , Mariusz Michalczykb, Wiktor Zierkiewiczb, a Department of Chemistry and Biochemistry, Utah State University Logan, Utah 84322-0300, United States b Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland ARTICLE INFO ABSTRACT Keywords: Four H-binding HCl and HF molecules position themselves at the vertices of a tetrahedron when surrounding a Tetrahedral central Cl−. Halogen bonding BrF and ClF form a slightly distorted tetrahedron, a tendency that is amplified for QTAIM ClCN which forms a trigonal pyramid. Chalcogen bonding SF2, SeF2, SeFMe, and SeCSe occupy one hemisphere NBO of the central ion, leaving the other hemisphere empty. This pattern is repeated for pnicogen bonding PF3, SeF3 Cl− and AsCF. The clustering of solvent molecules on one side of the Cl− is attributed to weak attractive interactions Na+ between them, including chalcogen, pnicogen, halogen, and hydrogen bonds. Binding energies of four solvent molecules around a central Na+ are considerably reduced relative to chloride, and the geometries are different, with no empty hemisphere. The driving force maximizes the number of electronegative (F or O) atoms close to the Na+, and the presence of noncovalent bonds between solvent molecules. 1. Introduction particular, the S, Se, etc group can engage in chalcogen bonds (YBs) [19–25], and the same is true of the P, As family which forms pnicogen The hydrogen bond (HB) is arguably the most important and in- bonds (ZBs) [26–34].
    [Show full text]
  • Quantitative Analysis of Hydrogen and Chalcogen Bonds in Two Pyrimidine
    Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2020 Quantitative analysis of hydrogen and chalcogen bonds in two pyrimidine-5-carbonitrile derivatives, potential DHFR inhibitors: an integrated crystallographic and theoretical study Al-Wahaibi, Lamya H ; Chakraborty, Kushumita ; Al-Shaalan, Nora H ; Syed Majeed, Mohamed Yehya Annavi ; Blacque, Olivier ; Al-Mutairi, Aamal A ; El-Emam, Ali A ; Percino, M Judith ; Thamotharan, Subbiah Abstract: Two potential bioactive pyrimidine-5-carbonitrile derivatives have been synthesized and char- acterized by spectroscopic techniques (1H and 13C-NMR) and the three dimensional structures were elucidated by single crystal X-ray diffraction at low temperature (160 K). In both structures, the molec- ular conformation is locked by an intramolecular C–H฀C interaction involving the cyano and CH of the thiophene and phenyl rings. The intermolecular interactions were analyzed in a qualitative man- ner based on the Hirshfeld surface and 2D-fingerprint plots. The results suggest that the phenyl and thiophene moieties have an effect on the crystal packing. For instance, the chalcogen bonds areonly preferred in the thiophene derivative. However, both structures uses a common N–H฀O hydrogen bond motif. Moreover, the structures of 1 and 2 display 1D isostructurality and molecular chains stabilize by intermolecular N–H฀O and N–H฀N hydrogen bonds. The nature and extent of different non-covalent interactions were further characterized by the topological parameters derived from the quantum the- ory of atoms-in-molecules approach. This analysis indicates that apart from N–H฀O hydrogen bonds, other non-covalent interactions are closed-shell in nature.
    [Show full text]
  • Frontiers in Halogen and Chalcogen-Bond Donor
    DOI: 10.1002/cctc.201901215 Minireviews 1 2 3 Frontiers in Halogen and Chalcogen-Bond Donor 4 5 Organocatalysis 6 [a] [a] [a] 7 Julia Bamberger, Florian Ostler, and Olga García Mancheño* 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 ChemCatChem 2019, 11, 1–15 1 © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim These are not the final page numbers! �� Wiley VCH Mittwoch, 21.08.2019 1999 / 145245 [S. 1/15] 1 Minireviews 1 Non-covalent molecular interactions on the basis of halogen Being particularly relevant in the binding of “soft” substrates, 2 and chalcogen bonding represent a promising, powerful the similar strength to hydrogen bonding interactions and its 3 catalytic activation mode. However, these “unusual” non- higher directionality allows for solution-phase applications with 4 covalent interactions are typically employed in the solid state halogen and chalcogen bonding as the key interaction. In this 5 and scarcely exploited in catalysis. In recent years, an increased mini-review, the special features, state-of-the-art and key 6 interest in halogen and chalcogen bonding have been awaken, examples of these so-called σ-hole interactions in the field of 7 as they provide profound characteristics that make them an organocatalysis are presented. 8 appealing alternative to the well-explored hydrogen bonding. 9 10 1. Introduction including crystal engineering,[8] supramolecular[9] and medicinal 11 chemistry.[8a,10] Besides the correlation to the electrostatic 12 To achieve an effective catalytic transformation, the structural potential, also charge transfer and dispersion is believed to give 13 design of selective catalyst structures requires the correct rise to σ-hole interactions.[11] Associated with σ* orbitals, the σ- 14 manipulation of the energetic and stereochemical features of hole deepens with heavier atoms (going from the top to the 15 intermolecular forces.
    [Show full text]
  • Theoretical Study on the Noncovalent Interactions Involving Triplet Diphenylcarbene
    Theoretical Study on the Noncovalent Interactions Involving Triplet Diphenylcarbene Chunhong Zhao Hebei Normal University Huihua College Hui Lin Hebei Normal University Aiting Shan Hebei Normal University Shaofu Guo Hebei Normal University Huihua College Xiaoyan Li Hebei Normal University Xueying Zhang ( [email protected] ) Hebei Normal University https://orcid.org/0000-0003-1598-8501 Research Article Keywords: triplet diphenylcarbene, noncovalent interaction, electron density shift, electron spin density Posted Date: May 19th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-445417/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Version of Record: A version of this preprint was published at Journal of Molecular Modeling on July 9th, 2021. See the published version at https://doi.org/10.1007/s00894-021-04838-6. Page 1/21 Abstract The properties of some types of noncovalent interactions formed by triplet diphenylcarbene (DPC3) have been investigated by means of density functional theory (DFT) calculations and quantum theory of 3 atoms in molecules (QTAIM) studies. The DPC ···LA (LA = AlF3, SiF4, PF5, SF2, ClF) complexes have been analyzed from their equilibrium geometries, binding energies, charge transfer and properties of electron 3 density. The triel bond in the DPC ···AlF3 complex exhibits a partially covalent nature, with the binding energy − 65.7kJ/mol. The tetrel bond, pnicogen bond, chalcogen bond and halogen bond in the DPC3···LA (LA = SiF4, PF5, SF2, ClF) complexes show the character of a weak closed-shell noncovalent interaction. Polarization plays an important role in the formation of the studied complexes.
    [Show full text]
  • Differential Binding of Tetrel-Bonding Bipodal Receptors to Monatomic and Polyatomic Anions
    molecules Article Differential Binding of Tetrel-Bonding Bipodal Receptors to Monatomic and Polyatomic Anions Steve Scheiner Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA; [email protected]; Tel.: +435-797-7419 Received: 26 December 2018; Accepted: 5 January 2019; Published: 9 January 2019 Abstract: Previous work has demonstrated that a bidentate receptor containing a pair of Sn atoms can engage in very strong interactions with halide ions via tetrel bonds. The question that is addressed here concerns the possibility that a receptor of this type might be designed that would preferentially bind a polyatomic over a monatomic anion since the former might better span the distance between − − − − the two Sn atoms. The binding of Cl was thus compared to that of HCOO , HSO4 , and H2PO4 with a wide variety of bidentate receptors. A pair of SnFH2 groups, as strong tetrel-binding agents, were first added to a phenyl ring in ortho, meta, and para arrangements. These same groups were also added in 1,3 and 1,4 positions of an aliphatic cyclohexyl ring. The tetrel-bonding groups were placed at the termini of (-C≡C-)n (n = 1,2) extending arms so as to further separate the two Sn atoms. Finally, the Sn atoms were incorporated directly into an eight-membered ring, rather than as − − − − appendages. The ordering of the binding energetics follows the HCO2 > Cl > H2PO4 > HSO4 general pattern, with some variations in selected systems. The tetrel bonding is strong enough that in most cases, it engenders internal deformations within the receptors that allow them to engage in bidentate bonding, even for the monatomic chloride, which mutes any effects of a long Sn···Sn distance within the receptor.
    [Show full text]
  • Molecular Recognition by Chalcogen Bond
    Molecular Recognition by Chalcogen Bond: Selective Chargetransfer Crystal Formation of Dimethylnaphthalene with Selenadiazolotetracyanonaphthoquinodimethane Yusuke Ishigaki, Kota Asai, Henri-Pierre Jacquot de Rouville, Takuya Shimajiri, Valérie Heitz, Hiroshi Fujii-Shinomiya, Takanori Suzuki To cite this version: Yusuke Ishigaki, Kota Asai, Henri-Pierre Jacquot de Rouville, Takuya Shimajiri, Valérie Heitz, et al.. Molecular Recognition by Chalcogen Bond: Selective Chargetransfer Crystal Formation of Dimethyl- naphthalene with Selenadiazolotetracyanonaphthoquinodimethane. European Journal of Organic Chemistry, Wiley-VCH Verlag, In press, 10.1002/ejoc.202001554. hal-03114533 HAL Id: hal-03114533 https://hal.archives-ouvertes.fr/hal-03114533 Submitted on 19 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Molecular Recognition by Chalcogen Bond: Selective Charge- transfer Crystal Formation of Dimethylnaphthalene with Selenadiazolotetracyanonaphthoquinodimethane Yusuke Ishigaki,[a] Kota Asai,[a] Henri-Pierre Jacquot de Rouville,[b] Takuya Shimajiri,[a] Valérie Heitz,[b] Hiroshi Fujii-Shinomiya,[c,d] and Takanori Suzuki*[a] In memory of François Diederich and Tsutomu Miyashi Abstract: The title nonplanar electron acceptor (1) fused with a selenadiazole ring selectively forms a crystalline charge-transfer complex (CT crystal) with 2,6-dimethylnaphthalene (2,6-DMN). On the other hand, the sulfur analogue (2) has less recognition ability and forms CT crystals with both 2,6- and 2,7-DMN.
    [Show full text]
  • Catalysis with Chalcogen Bonds: Neutral Benzodiselenazole Scaffolds with High-Precision Cite This: Chem
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Catalysis with chalcogen bonds: neutral benzodiselenazole scaffolds with high-precision Cite this: Chem. Sci.,2017,8,8164 selenium donors of variable strength† Sebastian Benz, Jiri Mareda, Celine´ Besnard, Naomi Sakai and Stefan Matile * The benzodiselenazoles (BDS) introduced in this report fulfill, for the first time, all the prerequisites for non- covalent high-precision chalcogen-bonding catalysis in the focal point of conformationally immobilized s holes on strong selenium donors in a neutral scaffold. Rational bite-angle adjustment to the long Se–C bonds was the key for BDS design. For the unprecedented BDS motif, synthesis of 12 analogs from Received 4th September 2017 o-xylene, crystal structure, s hole variation strategies, optoelectronic properties, theoretical and Accepted 6th October 2017 experimental anion binding as well as catalytic activity are reported. Chloride binding increases with the DOI: 10.1039/c7sc03866f depth of the s holes down to KD ¼ 11 mM in THF. Catalytic activities follow the same trend and rsc.li/chemical-science culminate in rate enhancements for transfer hydrogenation of quinolines beyond 100 000. Creative Commons Attribution 3.0 Unported Licence. The integration of new interactions into functional systems is attractive to stabilize anionic transition states with high preci- an objective of highest, most fundamental importance.1–7 It sion in the focal point of the two cofacial s holes (Fig. 1),8 expands our ability to create function and promises access to but they are limited to weak sulfur donors. Bis(2- new properties. In organocatalysis, a renewed interest in the selanylbenzimidazolium)s, used in stoichiometric amounts, integration of conventional interactions such as dispersion provide access to more powerful selenium donors but suffer forces,3 ion pairing4 or cation–p interactions5 accounts for from lack of precision due to conformational exibility and much recent progress in the eld.
    [Show full text]
  • Strength of the Pnicogen Bond in Complexes Involving Group Va Elements N, P, and As Dani Setiawan, Elfi Kraka,* and Dieter Cremer*
    Article pubs.acs.org/JPCA Strength of the Pnicogen Bond in Complexes Involving Group Va Elements N, P, and As Dani Setiawan, Elfi Kraka,* and Dieter Cremer* Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave, Dallas, Texas 75275-0314, United States *S Supporting Information ··· ABSTRACT: A set of 36 pnicogen homo- and heterodimers, R3E ER3 and ··· ′ ′ ff R3E E R3, involving di erently substituted group Va elements E = N, P, and As has been investigated at the ωB97X-D/aug-cc-pVTZ level of theory to determine the strength of the pnicogen bond with the help of the local E···E′ stretching force constants ka. The latter are directly related to the amount of charge transferred from an E donor lone pair orbital to an E′ acceptor σ* orbital, in the sense of a through-space anomeric effect. This leads to a buildup of electron density in the intermonomer region and a distinct pnicogen bond strength order quantitatively assessed via ka. However, the complex binding energy ΔE depends only partly on the pnicogen bond strength as H,E- attractions, H-bonding, dipole−dipole, or multipole−multipole attractions also contribute to the stability of pnicogen bonded dimers. A variation from through-space anomeric to second order hyperonjugative, and skewed π,π interactions is observed. Charge transfer into a π* substituent orbital of the acceptor increases the absolute value of ΔE by electrostatic effects but has a smaller impact on the pnicogen bond strength. A set of 10 dimers obtains its stability from covalent pnicogen bonding whereas all other dimers are stabilized by electrostatic interactions.
    [Show full text]
  • Halogen Bonding, Chalcogen Bonding, Pnictogen Bonding, Tetrel Bonding: Origins, Current Status and Discussion
    Faraday Discussions Cite this: Faraday Discuss.,2017,203, 485 View Article Online PAPER View Journal | View Issue Halogen bonding, chalcogen bonding, pnictogen bonding, tetrel bonding: origins, current status and discussion Lee Brammer Received 26th September 2017, Accepted 27th September 2017 DOI: 10.1039/c7fd00199a The role of the closing lecture in a Faraday Discussion is to summarise the contributions made to the Discussion over the course of the meeting and in so doing capture the main themes that have arisen. This article is based upon my Closing Remarks Lecture at Creative Commons Attribution 3.0 Unported Licence. the 203rd Faraday Discussion meeting on Halogen Bonding in Supramolecular and Solid State Chemistry, held in Ottawa, Canada, on 10–12th July, 2017. The Discussion included papers on fundamentals and applications of halogen bonding in the solid state and solution phase. Analogous interactions involving main group elements outside group 17 were also examined. In the closing lecture and in this article these contributions have been grouped into the four themes: (a) fundamentals, (b) beyond the halogen bond, (c) characterisation, and (d) applications. The lecture and paper also include a short reflection on past work that has a bearing on the Discussion. This article is licensed under a 1. Introduction: history and foundations Open Access Article. Published on 05 2017. Downloaded 23/09/2021 8:43:06 . Halogen bonding in its modern incarnation has been the subject of study for approximately 20 years, but is underpinned by many important earlier contri- butions, sometimes noted in historic introductions to the eld and sometimes overlooked. Early papers from the 19th century have more recently been recog- nised as being observations of halogen bonding, the earliest among these being 1,2 the association of iodine (I2) with ammonia.
    [Show full text]
  • Does Oxygen Feature Chalcogen Bonding?
    molecules Article Does Oxygen Feature Chalcogen Bonding? Pradeep R. Varadwaj 1,2 1 Department of Chemical System Engineering, School of Engineering, The University of Tokyo 7-3-1, Tokyo 113-8656, Japan; [email protected] or [email protected] 2 The National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8560, Japan Received: 20 July 2019; Accepted: 28 August 2019; Published: 30 August 2019 Abstract: Using the second-order Møller–Plesset perturbation theory (MP2), together with Dunning’s all-electron correlation consistent basis set aug-cc-pVTZ, we show that the covalently bound oxygen atom present in a series of 21 prototypical monomer molecules examined does conceive a positive (or a negative) σ-hole. A σ-hole, in general, is an electron density-deficient region on a bound atom M along the outer extension of the R–M covalent bond, where R is the reminder part of the molecule, and M is the main group atom covalently bonded to R. We have also examined some exemplar 1:1 binary complexes that are formed between five randomly chosen monomers of the above series and the nitrogen- and oxygen-containing Lewis bases in N2, PN, NH3, and OH2. We show that the O-centered positive σ-hole in the selected monomers has the ability to form the chalcogen bonding interaction, and this is when the σ-hole on O is placed in the close proximity of the negative site in the partner molecule. Although the interaction energy and the various other 12 characteristics revealed from this study indicate the presence of any weakly bound interaction between the monomers in the six complexes, our result is strongly inconsistent with the general view that oxygen does not form a chalcogen-bonded interaction.
    [Show full text]