1
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Del Angel Cruz D, Galvez Vallejo JL, Gordon MS. Analysis of the bonding in tetrahedrane and phosphorus-substituted tetrahedranes. Phys Chem Chem Phys 2023; 25:27276-27292. [PMID: 37791459 DOI: 10.1039/d3cp03619g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The bonding structures of tetrahedrane, phosphatetrahedrane, diphosphatetrahedrane and triphosphatetrahedrane are studied by employing an intrinsic quasi-atomic orbital analysis. Ethane, cyclopropane and tetrahedral P4 are employed as reference systems. The orbital analysis is paired with the computation of strain energies via isodesmic reactions. The results show that the increase in geometric strain upon transition from ethane to cyclopropane to tetrahedrane weakens the CC bonds, despite leading to shorter C-C interatomic distances. With the increase in strain, the orbitals centered on C and involved in the bonding of the cage structure are observed to have elevated p-character, and the orbital structure of C deviates from sp3 hybridization. The systematic substitution of CH groups by P atoms in the cage structure of tetrahedrane leads to stronger CC bonds, larger angles in the cage structures of the resulting phosphatetrahedranes, lower p-character in the orbitals involved in the bonding of the cages, and lower strain energies. It is found that P is more amenable to strained molecular arrangements than is C, and that the propensity of a given atom to hybridize s and p functions, or the lack thereof, has implications in the stability of molecules with strained geometries. The combination of the calculations presented here with the existing literature provides insight into the apparent propensity of tetrahedrane and P4 to 'break' their tetrahedral structures. Trends in the bonding interactions, such as bond strengths, s- and p-orbital characters and charge transfer are identified and related to the strain energy observed in each of the analyzed systems.
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Affiliation(s)
| | - Jorge L Galvez Vallejo
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
- School of Computing, Australian National University, Canberra, ACT 2601, Australia
| | - Mark S Gordon
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
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2
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Zheng X, Crumpton AE, Protchenko AV, Ellwanger MA, Heilmann A, Aldridge S. Synthesis of Homo-Metallic Heavier Analogues of Cyclobutene and the Cyclobutadiene Dianion. Chemistry 2023; 29:e202300006. [PMID: 36594576 PMCID: PMC10947146 DOI: 10.1002/chem.202300006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/04/2023]
Abstract
The reduction of the boryl-substituted SnII bromide {(HCDippN)2 B}Sn(IPrMe)Br with 1.5 equivalents of potassium graphite leads to the generation of the cyclic tetratin tetraboryl system K2 [Sn4 {B(NDippCH)2 }4 ], a homo-metallic heavier analogue of the cyclobutadiene dianion. This system is non-aromatic as determined by Nucleus Independent Chemical Shift Calculations (NICS(0)=-0.28, NICS(1)=-3.17), with the primary contributing resonance structures shown by Natural Resonance Theory (NRT) to involve a Sn=Sn double bond and 1,2-localized negative charges. Abstraction of the K+ cations or oxidation leads to contraction or cleavage of the Sn4 unit, respectively, while protonation generates the neutral dihydride 1,2-Sn4 {B(NDippCH)2 }4 H2 (a heavier homologue of cyclobutene) in a manner consistent with the predicted charge distribution in the [Sn4 {B(NDippCH)2 }4 ]2- dianion.
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Affiliation(s)
- Xiongfei Zheng
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOX1 3QROxfordUK
| | - Agamemnon E. Crumpton
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOX1 3QROxfordUK
| | - Andrey V. Protchenko
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOX1 3QROxfordUK
| | - Mathias A. Ellwanger
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOX1 3QROxfordUK
| | - Andreas Heilmann
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOX1 3QROxfordUK
| | - Simon Aldridge
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOX1 3QROxfordUK
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3
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Rosenberg M, Brinker UH. Carbene Routes to Cyclopropatetrahedrane. J Org Chem 2022; 87:16902-16906. [PMID: 36446051 PMCID: PMC9764353 DOI: 10.1021/acs.joc.2c02217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Indexed: 11/30/2022]
Abstract
The formation of cyclopropatetrahedrane (tetracyclo[2.1.0.01,3.02,4]pentane) via four different carbene reactions is computed using the (U)CCSD(T)(full)/cc-pVTZ//(U)ωB97X-D/cc-pVTZ + 1.3686(EZPVE) theoretical model. Intrinsic reaction coordinate plots confirm that each carbene is directly linked to cyclopropatetrahedrane via a unique cyclopropanation step. Each elementary step is assessed according to the structure and energy of its transition state.
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Affiliation(s)
- Murray
G. Rosenberg
- Department
of Chemistry, The State University of New
York at Binghamton, P.O. Box 6000, Binghamton, New York 13902-6000, United States
| | - Udo H. Brinker
- Institute
of Organic Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria
- Department
of Chemistry, The State University of New
York at Binghamton, P.O. Box 6000, Binghamton, New York 13902-6000, United States
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4
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Körner L, Ho LP, Puchta R, Stanger A, Tamm M. Dimorpholinoacetylene and Its Use for the Synthesis of Tetraaminocyclobutadiene Species. Chemistry 2022; 28:e202202737. [PMID: 36148808 PMCID: PMC9828195 DOI: 10.1002/chem.202202737] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Indexed: 01/12/2023]
Abstract
The new diaminoacetylene (DAA) dimorpholinoacetylene (3) was prepared from 1,1-dimorpholinoethene (1) by bromination to form the dibromoketene aminal 2, which upon lithiation afforded 3 through a Fritsch-Buttenberg-Wiechell rearrangement. Heating 3 at elevated temperatures resulted in a complete conversion into the dimer 1,1,2,4-tetramorpholino-1-buten-3-yne (4), which was used for the synthesis of four-membered cyclic bent allene (CBA) transition-metal complexes of the type [(CBA)MLn ] (5-7; MLn =AuCl, RhCl(COD), RhCl(CO)2 ; CBA=1,3,4,4-tetramorpholino-1,2-cyclobutadiene; COD=1,5-cyclooctadiene). The reaction of 3 with tetraethylammonium bromide gave 1,2,3,4-tetramorpholinocyclobutenylium bromide (8), which reacted with bromine to form 1,2,3,4-tetra(morpholino)cyclobutenediylium bis(tribromide) (9). Compound 9 represents the first fully characterized compound containing a tetraaminocyclobutadiene dication and displays a nearly planar C4 N4 core as shown by X-ray diffraction analysis. Detailed quantum chemical calculations were performed to assess the aromaticity of tetraaminocyclubutadiene dications by employing the Nucleus Independent Chemical Shift (NICS) method and current density analysis.
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Affiliation(s)
- Lukas Körner
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Luong Phong Ho
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Ralph Puchta
- Department Chemie und PharmazieFriedrich-Alexander Universität Erlangen-NürnbergEgerlandstr. 191058ErlangenGermany
| | - Amnon Stanger
- Schulich Department of Chemistry, TechnionHaifa32000Israel
| | - Matthias Tamm
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
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5
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Riu MLY, Eckhardt AK, Cummins CC. Reactions of Tri- tert-Butylphosphatetrahedrane as a Spring-Loaded Phosphinidene Synthon Featuring Nickel-Catalyzed Transfer to Unactivated Alkenes. J Am Chem Soc 2022; 144:7578-7582. [PMID: 35437987 DOI: 10.1021/jacs.2c02236] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cage-opening reactions of the highly strained tri-tert-butylphosphatetrahedrane (1), shown here to function as a synthon of (tri-tert-butylcyclopropenyl)phosphinidene, are described. Treatment of 1 with a base-stabilized silylene led to the corresponding phosphasilene, which was isolated in 72% yield as a red crystalline solid. Phosphinidene transfer was also observed when 1 (2 equiv) was combined with the Wittig reagent Ph3PCH2 to form a diphosphirane (50% isolated yield). The reaction is proposed to proceed through a generated phosphaalkene intermediate, which was characterized by NMR spectroscopy. In addition, we report on nickel-catalyzed phosphinidene transfer to styrene, ethylene, neohexene, and 1,3-cyclohexadiene; the corresponding phosphiranes were isolated in 51-64% yield. Computational studies suggest the intermediacy of a nickel phosphinidene species. Treatment of the ethylene-derived phosphirane product with triflic acid delivered elimination of [tBu3C3]OTf and formation of a P-H bond, illustrating the ability of the tri-tert-butyl cyclopropenyl group to serve as a protecting group that is removable following phosphinidene transfer.
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Affiliation(s)
- Martin-Louis Y Riu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - André K Eckhardt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Christopher C Cummins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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6
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Ghorai S, Meena R, Joseph AP, Jemmis ED. Comparison of RNC Coupling and CO Coupling Mediated by Cr-Cr Quintuple Bond and B-B Multiple Bonds: Main Group Metallomimetics. J Phys Chem A 2021; 125:7207-7216. [PMID: 34402622 DOI: 10.1021/acs.jpca.1c05185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A theoretical analysis of reductive coupling of isocyanide and CO mediated by a Cr-Cr quintuple bonded complex and B-B multiple bonded complexes shows how the difference in donor-acceptor capability of isocyanide and CO ligands controls the product distributions. In the case of CO, the Cr-Cr quintuple bonded complex is unable to show C-C coupling due to the high π- back bonding possibility of CO and the reaction follows the singlet potential energy surface throughout, whereas, in the case of isocyanide, less π- back bonding possibility allows the reactions to undergo a spin transition and gives a series of products with different spin multiplicities. Similarly, reactions of B-B multiple bonded complexes with CO and isocyanides are also controlled by donor-acceptor capabilities of ligands, and the C-C coupling takes place by changing the oxidation state of the boron centers from +I to +II, in contrast to the classical main group mediated reactions where stable oxidation states are always preserved. This part of the main group chemistry which is dominated by donor-acceptor bonding interaction is more likely to follow transition metal behavior.
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Affiliation(s)
- Sagar Ghorai
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore-560012, India
| | - Raghavendra Meena
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore-560012, India
| | - Anju P Joseph
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore-560012, India
| | - Eluvathingal D Jemmis
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore-560012, India
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7
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Riu MLY, Bistoni G, Cummins CC. Understanding the Nature and Properties of Hydrogen-Hydrogen Bonds: The Stability of a Bulky Phosphatetrahedrane as a Case Study. J Phys Chem A 2021; 125:6151-6157. [PMID: 34236879 DOI: 10.1021/acs.jpca.1c04046] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recently, the first mixed C/P phosphatetrahedranes (tBuC)3P and (tBuCP)2 were reported. Unlike (tBuCP)2, (tBuC)3P exhibits remarkable thermal stability, which can be partially attributed to a network of nine hydrogen-hydrogen bonds (HHBs) localized between the tert-butyl substituents. The stabilizing contribution arising from this network of HHBs was obtained from local energy decomposition (LED) analysis calculated at the domain-based local pair natural orbital CCSD(T) (DLPNO-CCSD(T)) level of theory. These calculations suggest that each HHB contributes approximately -0.7 kcal/mol of stabilization; however, the net stabilization energy likely lies between -0.25 and -0.5 kcal/mol because of steric repulsion. Spatial analysis of the London dispersion energy via a dispersion interaction density (DID) plot reveals that the DID surface is localized at key C-H groups involved in HHBs, consistent with London dispersion interactions predominantly arising from HHBs. In addition, we present a computed mechanism that supports a phosphinidenoid species as a key reaction intermediate in the synthesis of (tBuC)3P.
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Affiliation(s)
- Martin-Louis Y Riu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Christopher C Cummins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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8
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Wolf ME, Doty EA, Turney JM, Schaefer Iii HF. Highly Strained Pn(CH) 3 (Pn = N, P, As, Sb, Bi) Tetrahedranes: Theoretical Characterization. J Phys Chem A 2021; 125:2612-2621. [PMID: 33730491 DOI: 10.1021/acs.jpca.1c01022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent experimental research by Cummins and co-workers has established the existence of a tetrahedrane molecule with one CH moiety replaced by phosphorus. We present here the first theoretical studies of the entire Pn(CH)3 (Pn = N, P, As, Sb, Bi) class of molecules. Geometries are obtained at the highly reliable CCSD(T)/aug-cc-pwCVTZ(-PP) level of theory. Harmonic vibrational frequencies are determined and analyzed to confirm the nature of each stationary point and provide helpful findings that may aid in the detection of each species. Most notable is the result that the geometric parameters associated with the (CH)3 moiety in the tetrahedranes exhibit little change under pnictogen substitution, while the Pn-C bonds and C-Pn-C bond angles greatly increase and decrease, respectively. Strain energies are predicted and range from 122.3 kcal mol-1 (N(CH)3) to 99.4 kcal mol-1 (Bi(CH)3) at the DF-CCSD(T)//B3LYP-D3/aug-cc-pV(T+d)Z(-PP) level of theory. The obtained geometries are further analyzed with Natural Bond Orbital (NBO) methods to understand the bonding and electronic structure of each species. We also provide insight into how different substituents can help make the tetrahedrane structure more energetically favorable due to electron delocalization into substituent antibonding orbitals. The effect of additional delocalization also weakens the Pn-C bonds, especially for the heavier pnictogens. This work concludes with a list of considerations that summarize our key findings and motivate future work aimed at producing novel pnictogen-substituted tetrahedrane molecules.
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Affiliation(s)
- Mark E Wolf
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Elizabeth A Doty
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States.,Department of Chemistry, Calvin University, 3201 Burton SE, Grand Rapids, Michigan 49546, United States
| | - Justin M Turney
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Henry F Schaefer Iii
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
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9
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Muz İ, Kurban M. Ab initio study of structural and electronic properties of SinC5-nH8 (n = 0–5) series: Probing the 2D to 3D structural transition. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Sun Z, Launder AM, Schaefer HF. Prediction and Characterization of Alkaline-Earth (M=Be, Mg, Ca, Sr, and Ba) Metallacyclopentadienes and Relevant Derivatives. ChemistrySelect 2017. [DOI: 10.1002/slct.201601911] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Zhi Sun
- Center for Computational Quantum Chemistry; University of Georgia; Athens, Georgia 30602 USA
| | - Andrew M. Launder
- Center for Computational Quantum Chemistry; University of Georgia; Athens, Georgia 30602 USA
| | - Henry F. Schaefer
- Center for Computational Quantum Chemistry; University of Georgia; Athens, Georgia 30602 USA
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11
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Liptrot DJ, Power PP. London dispersion forces in sterically crowded inorganic and organometallic molecules. Nat Rev Chem 2017. [DOI: 10.1038/s41570-016-0004] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Setiawan D, Kraka E, Cremer D. Quantitative Assessment of Aromaticity and Antiaromaticity Utilizing Vibrational Spectroscopy. J Org Chem 2016; 81:9669-9686. [DOI: 10.1021/acs.joc.6b01761] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dani Setiawan
- Computational and Theoretical
Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275-0314, United States
| | - Elfi Kraka
- Computational and Theoretical
Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275-0314, United States
| | - Dieter Cremer
- Computational and Theoretical
Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275-0314, United States
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13
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Gas phase enthalpies of formation, isomerization, and disproportionation of mono- through tetra-substituted tetrahedranes: A G4(MP2)/G4 theoretical study. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2015.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Koval VV, Minyaev RM, Minkin VI. Quantum chemical study of intramolecular rearrangements of the cyclooctatetraene complexes C8H8X (X = Mg, Si, S). RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2015. [DOI: 10.1134/s107042801503001x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Kobayashi Y, Nakamoto M, Inagaki Y, Sekiguchi A. Cross-coupling reaction of a highly strained molecule: synthesis of σ-π conjugated tetrahedranes. Angew Chem Int Ed Engl 2013; 52:10740-4. [PMID: 24038655 DOI: 10.1002/anie.201304770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Yuzuru Kobayashi
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan) http://www.chem.tsukuba.ac.jp/sekiguch/
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16
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Kobayashi Y, Nakamoto M, Inagaki Y, Sekiguchi A. Cross-Coupling Reaction of a Highly Strained Molecule: Synthesis of σ-π Conjugated Tetrahedranes. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Yang YF, Cheng GJ, Zhu J, Zhang X, Inoue S, Wu YD. Silicon-Containing Formal 4π-Electron Four-Membered Ring Systems: Antiaromatic, Aromatic, or Nonaromatic? Chemistry 2012; 18:7516-24. [DOI: 10.1002/chem.201103443] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Indexed: 11/08/2022]
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18
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Thompson SJ, Emmert FL, Slipchenko LV. Effects of Ethynyl Substituents on the Electronic Structure of Cyclobutadiene. J Phys Chem A 2012; 116:3194-201. [PMID: 22375728 DOI: 10.1021/jp2099202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
| | - Frank Lee Emmert
- Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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19
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Rayne S, Forest K. Isomerization energies of tetrahedranes to 1,3-cyclobutadienes: A challenge for theoretical methods. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.10.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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20
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Esselman BJ, McMahon RJ. Effects of Ethynyl Substitution on Cyclobutadiene. J Phys Chem A 2011; 116:483-90. [DOI: 10.1021/jp206478q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Brian J. Esselman
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Robert J. McMahon
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
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21
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WU HAISHUN, QIN XIAOFANG, JIAO HAIJUN. STRUCTURE AND STABILITY OF MONOCYCLIC $({\rm CH})_{4-n} ({\rm BL})_{n}^{2-}$(L = CO, N2, CS) DIANIONS AND THEIR DILITHIUM COMPLEXES. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633608003988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Structure and stability of monocyclic [Formula: see text] dianions ( L = CO , N 2, CS ) with 6π-electrons, which are isolobal with cyclobutadiene dianion [Formula: see text], have been investigated at the B3LYP and CCSD(T) levels of theory. ( CH )3( BL )2- have non-planar singlet ground states. [Formula: see text] have planar singlet ground states, while [Formula: see text] isomers have folded four-membered central rings. Both [Formula: see text] and [Formula: see text] have planar ground states, the ground state of [Formula: see text] has a six-membered ring with two bridging and one terminal CS. Both [Formula: see text] and [Formula: see text] have reduced aromaticity compared to [Formula: see text] as indicated by the less negative nucleus independent chemical shifts (NICS) values. The mono-, di- and trisubstituted ( CH )3( BL )2-, [Formula: see text], and [Formula: see text] also have reduced aromaticity, while the 1,3-substituted [Formula: see text] have positive NICS values due to the localization of the negative charge at the ring carbon centers. In addition, the electrostatic stabilization of Li + in favor of the singlet or triplet states depends on the nature of their structures.
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Affiliation(s)
- HAI-SHUN WU
- School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China
| | - XIAO-FANG QIN
- School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China
| | - HAIJUN JIAO
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße, 29a, 18059 Rostock, Germany
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22
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Inagaki Y, Nakamoto M, Sekiguchi A. Photoisomerization of Perfluoroaryltetrahedranes to Perfluoroarylcyclobutadienes. J Am Chem Soc 2011; 133:16436-9. [DOI: 10.1021/ja208354x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yusuke Inagaki
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Masaaki Nakamoto
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Akira Sekiguchi
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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23
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Sumita M, Saito K, Tateyama Y. Computational study on photo- and thermo-reactions between tetra-tert-butyl-substituted cyclobutadiene and tetrahedrane. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Zou W, Izotov D, Cremer D. New Way of Describing Static and Dynamic Deformations of the Jahn–Teller Type in Ring Molecules. J Phys Chem A 2011; 115:8731-42. [DOI: 10.1021/jp2041907] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Wenli Zou
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Dmitry Izotov
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Dieter Cremer
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
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Hayashi N, Sato K, Sato Y, Iwagami M, Nishimura N, Yoshino J, Higuchi H, Sato T. Elongation of phenoxide C-O bonds due to formation of multifold hydrogen bonds: statistical, experimental, and theoretical studies. J Org Chem 2011; 76:5747-58. [PMID: 21627124 DOI: 10.1021/jo200852r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Statistical studies using the Cambridge Structural Database have revealed that there are several elongated phenoxide C-O bonds. They are characterized by the formation of 3-fold (or occasionally 2-fold) hydrogen bonds to the phenoxide oxygen atoms, and their mean bond length extends up to 1.320 Å, which is quite different from the theoretically predicted carbon-oxygen bond length of C(6)H(5)O(-) (1.26 Å). Elongated phenoxide C-O bonds associated with the formation of 3-fold hydrogen bonds were also observed in the X-ray structures of proton-transfer complexes (2X-O(-))(TEAH(+))s derived from 5'-X-substituted 5,5''-dimethyl-1,1':3',1''-terphenyl-2,2',2''-triols (2X-OHs, where X = NO(2), CN, COOCH(3), Cl, F, H, and CH(3)) and triethylamine (TEA). By comparing the X-ray structures, C-O bond elongation was found to be only slightly affected by an electron-withdrawing substituent at the para position (X). This along with strong bathochromic shifts of N-H(···O(-)) and O-H(···O(-)) stretching vibrations in the IR spectra indicates that the elongated C-O bonds in (2X-O(-))(TEAH(+))s essentially have single-bond character. This is further confirmed by molecular orbital calculations on a model complex, showing that the negatively charged phenoxide oxygen atom is no longer conjugated to the central benzene ring, and the NICS values of the three benzene rings are virtually identical. However, C-O bond elongation in (2X-O(-))(TEAH(+))s was considerably influenced by a change in the hydrogen-bond geometry. This also suggests that hydrogen bonds significantly affect phenoxide C-O bond elongation.
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Affiliation(s)
- Naoto Hayashi
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan.
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26
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Lee VY, Sekiguchi A. Novel Organometallic Reagents: Geminal Dianionic Derivatives of the Heavy Group 14 Elements. Inorg Chem 2011; 50:12303-14. [PMID: 21630690 DOI: 10.1021/ic2006106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vladimir Ya. Lee
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Akira Sekiguchi
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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27
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Kim S, Wang S, Schaefer HF. Structures, Energetics, and Aromaticities of the Tetrasilacyclobutadiene Dianion and Related Compounds: (Si4H4)2–, (Si4H4)2–·2Li+, [Si4(SiH3)4]2–·2Li+, [Si4(SiH3)4]2–·2Na+, and [Si4(SiH3)4]2–·2K+. J Phys Chem A 2011; 115:5478-87. [DOI: 10.1021/jp202671u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sunghwan Kim
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Suyun Wang
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Henry F. Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
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28
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Nakamoto M, Inagaki Y, Ochiai T, Tanaka M, Sekiguchi A. Cyclobutadiene to tetrahedrane: Valence isomerization induced by one-electron oxidation. HETEROATOM CHEMISTRY 2011. [DOI: 10.1002/hc.20699] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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29
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Lee VY, Ito Y, Yasuda H, Takanashi K, Sekiguchi A. From Tetragermacyclobutene to Tetragermacyclobutadiene Dianion to Tetragermacyclobutadiene Transition Metal Complexes. J Am Chem Soc 2011; 133:5103-8. [DOI: 10.1021/ja111596g] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vladimir Ya. Lee
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Yuki Ito
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Hiroyuki Yasuda
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Kazunori Takanashi
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Akira Sekiguchi
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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Wu Y, Jiang J, Lu H, Wang Z, Perez‐Peralta N, Islas R, Contreras M, Merino G, Wu JI, von Ragué Schleyer P. Starlike Aluminum–Carbon Aromatic Species. Chemistry 2010; 17:714-9. [DOI: 10.1002/chem.201001266] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Indexed: 11/06/2022]
Affiliation(s)
- Yan‐Bo Wu
- College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing, 100049 (P.R. China), Fax: (+86) 8825‐6693
- Institute of Molecular Science the Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Shanxi University, Taiyuan, 030006, Shanxi (P.R. China)
| | - Jin‐Liang Jiang
- College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing, 100049 (P.R. China), Fax: (+86) 8825‐6693
| | - Hai‐Gang Lu
- Institute of Molecular Science the Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Shanxi University, Taiyuan, 030006, Shanxi (P.R. China)
| | - Zhi‐Xiang Wang
- College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing, 100049 (P.R. China), Fax: (+86) 8825‐6693
| | - Nancy Perez‐Peralta
- Departamento de Química, Universidad de Guanajuato, Noria Alta s/n C.P. 36050, Guanajuato, Gto. (México), Fax: (+52) 473 7320006
| | - Rafael Islas
- Departamento de Química, Universidad de Guanajuato, Noria Alta s/n C.P. 36050, Guanajuato, Gto. (México), Fax: (+52) 473 7320006
| | - Maryel Contreras
- Departamento de Química, Universidad de Guanajuato, Noria Alta s/n C.P. 36050, Guanajuato, Gto. (México), Fax: (+52) 473 7320006
| | - Gabriel Merino
- Departamento de Química, Universidad de Guanajuato, Noria Alta s/n C.P. 36050, Guanajuato, Gto. (México), Fax: (+52) 473 7320006
| | - Judy I‐Chia Wu
- Center for Computational Chemistry, University of Georgia, Athens, GA 30602 (USA), Fax: (+1) 706‐542‐7514
| | - Paul von Ragué Schleyer
- Center for Computational Chemistry, University of Georgia, Athens, GA 30602 (USA), Fax: (+1) 706‐542‐7514
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31
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Sumita M, Saito K. Ground state potential energy surface between cyclobutadiene and tetrahedrane looked down from S1/S0 conical intersections. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.04.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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32
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Menke JL, Patterson EV, McMahon RJ. Effects of Cyano Substituents on Cyclobutadiene and Its Isomers. J Phys Chem A 2010; 114:6431-7. [DOI: 10.1021/jp101963p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Jessica L. Menke
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin, 53706-1322, Department of Chemistry, Truman State University, 100 Normal Avenue, Kirksville, Missouri, 63501-4200
| | - Eric V. Patterson
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin, 53706-1322, Department of Chemistry, Truman State University, 100 Normal Avenue, Kirksville, Missouri, 63501-4200
| | - Robert J. McMahon
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin, 53706-1322, Department of Chemistry, Truman State University, 100 Normal Avenue, Kirksville, Missouri, 63501-4200
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Wu JI, Evangelista FA, Schleyer PVR. Why Are Perfluorocyclobutadiene and Some Other (CF)nq Rings Non-Planar? Org Lett 2010; 12:768-71. [DOI: 10.1021/ol902866n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Judy I. Wu
- Center for Computational Chemistry, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2525, and Institut für Physikalische Chemie,Universität Mainz, D-55099 Mainz, Germany
| | - Francesco A. Evangelista
- Center for Computational Chemistry, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2525, and Institut für Physikalische Chemie,Universität Mainz, D-55099 Mainz, Germany
| | - Paul von Ragué Schleyer
- Center for Computational Chemistry, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2525, and Institut für Physikalische Chemie,Universität Mainz, D-55099 Mainz, Germany
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Balaban AT. Monocyclic Hetarenes with π-Electron Aromatic Sextet. ADVANCES IN HETEROCYCLIC CHEMISTRY 2010. [DOI: 10.1016/s0065-2725(10)09903-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Zubarev DY, Boldyrev AI. Multiple Aromaticity, Multiple Antiaromaticity, and Conflicting Aromaticity in Planar Clusters. NANOCLUSTERS - A BRIDGE ACROSS DISCIPLINES 2010. [DOI: 10.1016/b978-0-444-53440-8.00005-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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37
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Steinmann S, Jana D, Wu JC, Schleyer P, Mo Y, Corminboeuf C. Direct Assessment of Electron Delocalization Using NMR Chemical Shifts. Angew Chem Int Ed Engl 2009; 48:9828-33. [DOI: 10.1002/anie.200905390] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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38
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Cyclobutadiene dianion derivatives – Planar 4c,6e or three-dimensional 6c,6e aromaticity? ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.theochem.2008.05.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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40
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Takanashi K, Inatomi A, Lee VY, Nakamoto M, Ichinohe M, Sekiguchi A. Tetrakis(trimethylsilyl)cyclobutadiene Dianion Alkaline Earth Metal Salts: New Members of the 6π‐Electron Aromatics Family. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200800066] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kazunori Takanashi
- Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314
| | - Akira Inatomi
- Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314
| | - Vladimir Ya. Lee
- Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314
| | - Masaaki Nakamoto
- Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314
| | - Masaaki Ichinohe
- Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314
| | - Akira Sekiguchi
- Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314
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41
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Lee VY, Sekiguchi A. Cyclic polyenes of heavy group 14 elements: new generation ligands for transition-metal complexes. Chem Soc Rev 2008; 37:1652-65. [DOI: 10.1039/b800580j] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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42
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Firme CL, Antunes OAC, Esteves PM. Electronic Nature of Planar Cyclobutenyl Dication Derivatives. J Phys Chem A 2007; 111:11904-7. [DOI: 10.1021/jp075869j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Caio L. Firme
- Universidade Federal do Rio de Janeiro, Instituto de Química, Av. Athos da Silveira Ramos, 149, CT Bloco A, 6o andar, Cidade UniversitáriaIlha do Fundão, Rio de Janeiro, BR 21941-909, Brazil
| | - O. A. C. Antunes
- Universidade Federal do Rio de Janeiro, Instituto de Química, Av. Athos da Silveira Ramos, 149, CT Bloco A, 6o andar, Cidade UniversitáriaIlha do Fundão, Rio de Janeiro, BR 21941-909, Brazil
| | - Pierre M. Esteves
- Universidade Federal do Rio de Janeiro, Instituto de Química, Av. Athos da Silveira Ramos, 149, CT Bloco A, 6o andar, Cidade UniversitáriaIlha do Fundão, Rio de Janeiro, BR 21941-909, Brazil
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Wodrich MD, Wannere CS, Mo Y, Jarowski PD, Houk KN, Schleyer PVR. The Concept of Protobranching and Its Many Paradigm Shifting Implications for Energy Evaluations. Chemistry 2007; 13:7731-44. [PMID: 17607688 DOI: 10.1002/chem.200700602] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Branched alkanes like isobutane and neopentane are more stable than their straight chain isomers, n-butane and n-pentane (by 2 and 5 kcal mol(-1), respectively). Electron correlation is largely responsible. Branched alkanes have a greater number of net attractive 1,3-alkyl-alkyl group interactions, there are three such stabilizing 1,3 "protobranching" dispositions in isobutane, but only two in n-butane. Neopentane has six protobranches but n-pentane only three. Propane has one protobranch and is stabilized appreciably, by 2.8 kcal mol(-1), relative to methane and ethane. This value per protobranch also applies to the n-alkanes and cyclohexane. Consequently, energy evaluations employing alkane reference standards, for example, of small ring strain and stabilizations due to conjugation, hyperconjugation, and aromaticity, should be corrected for protobranching, for example, by employing Pople's isodesmic bond separation reaction method. This reduces the ring strain of cyclopropane to 19.2 from the conventional 27.7 kcal mol(-1), while the stabilization energies of alkenes and alkynes due to hyperconjugation (5.5 and 7.7 kcal mol(-1) for propene and propyne) and conjugation (14.8 and 27.1 kcal mol(-1) for butadiene and butadiyne) are considerably larger than the traditional estimates. Widely diverging literature evaluations of benzene resonance energy all give approximately 65 kcal mol(-1) after adjusting for conjugation, hyperconjugation, and protobranching "contaminations." The BLW (block localized wavefunction) method, which localizes pi bonds and precludes their interactions, largely confirms these stabilization estimates for hyperconjugation, conjugation, and aromaticity. Protobranching is seriously underestimated by theoretical computations at the HF and most DFT levels, which do not account for electron correlation satisfactorily. Such levels give bond separation energies, which can differ greatly from experimental values.
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Affiliation(s)
- Matthew D Wodrich
- Department of Chemistry and Center for Computational Chemistry, University of Georgia, Athens, GA 30602, USA
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Lee V, Sekiguchi A. Aromatizität von metallorganischen Verbindungen mit Gruppe-14-Elementen: experimentelle Aspekte. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604869] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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45
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Lee VY, Sekiguchi A. Aromaticity of Group 14 Organometallics: Experimental Aspects. Angew Chem Int Ed Engl 2007; 46:6596-620. [PMID: 17668903 DOI: 10.1002/anie.200604869] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The long story of aromatic compounds has extended over almost two centuries, since the discovery by Faraday of "bicarburet of hydrogen", or C(6)H(6), now called benzene. Since then, the chemistry of aromatic compounds has been developed extensively; this is reflected in the synthesis of novel classes of aromatic derivatives including charged species, nonclassical (Möbius, three-dimensional, homo-, metalla-) aromatics, and fullerenes. The theory of aromaticity has also undergone a spectacular evolution since the first definition of aromaticity by Hückel; the classification of aromaticity now requires the consideration of versatile criteria: energetic, structural, magnetic, among others. In this Review, we discuss the current state of affairs in the chemistry of aromatic compounds of the heavier Group 14 elements, the latest experimental achievements, as well as future prospects in the field.
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Affiliation(s)
- Vladimir Ya Lee
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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46
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Heavy analogues of the 6π-electron anionic ring systems: Cyclopentadienide ion and cyclobutadiene dianion. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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47
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Breher F. Stretching bonds in main group element compounds—Borderlines between biradicals and closed-shell species. Coord Chem Rev 2007. [DOI: 10.1016/j.ccr.2006.09.007] [Citation(s) in RCA: 271] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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48
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Abstract
At the B3LYP/6-311+G** and the BP86/6-311+G** levels of theory, BNN, H(3)BNN, NNBH(2)-BH(2)NN, (BNN)(2)H(2), NNBBNN, (BNN)(3) (+), (BNN)(4), (BNN)(4) (2+), (BNN)(4) (2-), B(4)(NN)(2), (BNN)(5) (-), (BNN)(6), (BNN)(7) (+), and (BNN)(8) (2+) are investigated. Neutral (BNN)(4) is aromatic with its triplet state but antiaromatic with its singlet state. (BNN)(4) dication favors D(2d) structure, while (BNN)(4) dianion favors a planar D(4h) structure. (BNN)(3) (+), (BNN)(4) (2-), (BNN)(5) (-), (BNN)(6), (BNN)(7) (+), (BNN)(7) (3-), (BNN)(8) (2+), and (BNN)(8) (2-) are all aromatic with planar monocyclic conformation, following the 4n + 2 rule. Moreover, according to the CASSCF and MRCI calculations, the planar B(4)(NN)(2) of D(2h) symmetry prefers to be a sigma-pi diradical in spite of open-shell singlet or triplet and is also aromatic. Akin to the sigma-pi back interaction in compounds containing transition metal, there exists the sigma-pi back interaction between boron and N(2) ligand among some species reported herein, which strengthens B(-)N bond but activates N-N bond, especially in (4)Sigma(-) BNN. The T-shaped structure lies lowest in energy among seven isomers of the (BNN)(2)H(2) dimer, and the parallel-displaced structure is favored between two isomers of the (BNN)(6) dimer.
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Affiliation(s)
- Qian Shu Li
- The Institute for Chemical Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
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Hohlneicher G, Packschies L, Weber J. On the σ,π-energy separation of the aromatic stabilization energy of cyclobutadiene. Phys Chem Chem Phys 2007; 9:2517-30. [PMID: 17508084 DOI: 10.1039/b700914n] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The separation of the aromatic stabilization energy (ASE) of cyclobutadiene (CBD) into a sigma- and a pi-component is reinvestigated. Eight different reactions are considered for this purpose. As expected, the total destabilization energies that result from these reactions depend only on the reference compound and not on the reaction itself. The heats of formation that can be obtained from the calculated reaction energies are in excellent agreement with the recently determined experimental value of 102.3 +/- 3.8 kcal mol(-1) (A. Fattahi, L. Liz, Z. Thian and S. R. Kass, Angew. Chem., Int. Ed., 2006, 45, 4984-4988). Evaluation of the angular strain in CBD from a newly considered reaction confirms earlier estimates and yields a strain energy of 34 +/- 3 kcal mol(-1). If referred to s-cis-butadiene this leads to an ASE of -37 +/- 4 kcal mol(-1) in close agreement with estimates provided by A. Fattahi, L. Liz, Z. Thian and S. R. Kass, Angew. Chem., Int. Ed., 2006, 45, 4984-4988; and by K. B. Wiberg, Chem. Rev., 2001, 101, 1317-1332. With s-trans-butadiene as reference we obtain -42 +/- 4 kcal mol(-1). This value is 8 to 10 kcal mol(-1) less destabilizing than recent estimates of A. A. Deniz, K. S. Peters and G. J. Snyder, Science, 1999, 286, 1119-1112; and Kovacević, D. Barić, Z. B. Maksić, T. Müller, J. Phys. Chem. A, 2004, 108, 9126-9133. Attempts to separate ASE(CBD) and E(strain)(CBD) into a sigma- and a pi-component do not lead to useful results. In contrast to ASE and E(strain) themselves, the sigma- and pi-components depend strongly on the applied reaction. A detailed analysis reveals that it is not possible to associate these components with only one of the molecules that participate in the reaction. The components depend on all of these molecules and therefore on the underlying reaction. Generally, components that result from a formal sigma,pi-energy separation of aromatic stabilization energies or strain energies cannot be considered as the sigma- and pi-components of these energies.
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Affiliation(s)
- Georg Hohlneicher
- Institut für Physikalische Chemie der Universität zu Köln, Luxemburger-Strasse 116, 50939 Köln, Germany.
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de Meijere A, Kozhushkov SI, Schill H. Three-Membered-Ring-Based Molecular Architectures. Chem Rev 2006; 106:4926-96. [PMID: 17165680 DOI: 10.1021/cr0505369] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Armin de Meijere
- Institut für Organische und Biomolekulare Chemie der Georg-August-Universität Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany
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