1
|
Vibrational Circular Dichroism Detects Symmetry Breaking due to Conformational Mobility in C2-Symmetry Chiral Molecules and Provides Further Insight into Inter-Chromophoric Interactions. Symmetry (Basel) 2020. [DOI: 10.3390/sym12111752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bicyclo[3.3.1]nonane-2,6-dione (1) and bicyclo[3.3.1]nona-3,7-diene-2,6-dione (2) have been examined by vibrational circular dichroism (VCD), which, as for most C2-symmetric systems, exhibits strong VCD signals. In the case of 2, VCD signals are stronger and sharper with several bisignate doublets; for 1, signals are less intense and broader. The VCD and IR spectra are excellently predicted by DFT calculations: only one conformer is present for 2, while for 1, three main conformers, related through concerted skeleton torsional motions are present (two of them being interchanged by C2-rotation). The VCD spectrum shows specific features for the different conformers, such that correct population factors are crucial for reproducing experimental data. Also, the TD-DFT prediction of ECD (electronic circular dichroism) spectra is good. By comparing the spectroscopic signature of the two molecules (both VCD and ECD) and by careful analysis of the theoretical results, the role of the C=C double bond in compound (2) is evidenced. The double bond contributes toward enhancing the CD response both electronically and vibrationally.
Collapse
|
2
|
Jones D, Wang F, Winkler D, Brunger M. The electronic structure of bicyclo[2.2.2]octa-2,5-dione. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
3
|
Paoloni L, Fusè M, Baiardi A, Barone V. Interplay of Stereoelectronic and Vibrational Modulation Effects in Tuning the UPS Spectra of Unsaturated Hydrocarbon Cage Compounds. J Chem Theory Comput 2020; 16:5218-5226. [PMID: 32667793 PMCID: PMC8009518 DOI: 10.1021/acs.jctc.0c00645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Indexed: 11/28/2022]
Abstract
The UPS spectra of six hydrocarbon cage compounds have been investigated by a Green-function approach in conjunction with a full harmonic treatment of vibrational modulation effects. The remarkable agreement with experimental results points out the reliability of the proposed computational approach and the strong interplay of stereoelectronic and vibrational effects in tuning the overall spectra.
Collapse
Affiliation(s)
- Lorenzo Paoloni
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, 56125 Pisa, Italy
| | - Marco Fusè
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, 56125 Pisa, Italy
| | - Alberto Baiardi
- Lab.
für Physikalische Chemie, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Vincenzo Barone
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, 56125 Pisa, Italy
| |
Collapse
|
4
|
Alabugin IV, Bresch S, Manoharan M. Hybridization trends for main group elements and expanding the Bent's rule beyond carbon: more than electronegativity. J Phys Chem A 2014; 118:3663-77. [PMID: 24773162 DOI: 10.1021/jp502472u] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Trends in hybridization were systematically analyzed through the combination of DFT calculations with NBO analysis for the five elements X (X = B, C, N, O, and F) in 75 HnX-YHm compounds, where Y spans the groups 13-17 of the periods 2-4. This set of substrates probes the flexibility of the hybridization at five atoms X through variations in electronegativity, polarizability, and orbital size of Y. The results illustrate the scope and limitations of the Bent's rule, the classic correlation between electronegativity and hybridization, commonly used in analyzing structural effects in carbon compounds. The rehybridization effects are larger for fluorine- and oxygen-bonds than they are in the similar bonds to carbon. For bonds with the larger elements Y of the lower periods, trends in orbital hybridization depend strongly on both electronegativity and orbital size. For charged species, the effects of substituent orbital size in the more polarizable bonds to heavier elements show a particularly strong response to the charge introduction at the central atom. In the final section, we provide an example of the interplay between hybridization effects with molecular structure and reactivity. In particular, the ability to change hybridization without changes in polarization provides an alternative way to control structure and reactivity, as illustrated by the strong correlation of strain in monosubstituted cyclopropanes with hybridization in the bond to the substituent.
Collapse
Affiliation(s)
- Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306-4390, United States
| | | | | |
Collapse
|
5
|
Chow TJ, Chu KP, Liu SS, Liu CY. A NMR Chemical Shift Analysis on Two Nonconjugated Tri-π-Systems. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.199900112] [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]
|
6
|
Verhoeven JW. From Close Contact to Long-Range Intramolecular Electron Transfer. ADVANCES IN CHEMICAL PHYSICS 2007. [DOI: 10.1002/9780470141656.ch13] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
|
7
|
Lockard JV, Zink JI, Luo Y, Weaver MN, Konradsson AE, Fowble JW, Nelsen SF. Excited-State Mixed-Valence Distortions in a Diisopropyl Diphenyl Hydrazine Cation. J Am Chem Soc 2006; 128:16524-31. [PMID: 17177401 DOI: 10.1021/ja0609093] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Excited-state mixed valence (ESMV) occurs in the 1,2-diphenyl-1,2-diisopropyl hydrazine radical cation, a molecule in which the ground state has a symmetrical charge distribution localized primarily on the hydrazine, but the phenyl to hydrazine charge-transfer excited state has two interchangeably equivalent phenyl groups that have different formal oxidation states. Electronic absorption and resonance Raman spectra are presented. The neighboring orbital model is employed to interpret the absorption spectrum and coupling. Resonance Raman spectroscopy is used to determine the excited-state distortions. The frequencies of the enhanced modes from the resonance Raman spectra are used together with the time-dependent theory of spectroscopy to fit the two observed absorption bands that have resolved vibronic structure. The origins of the vibronic structure and relationships with the neighboring orbital model are discussed.
Collapse
Affiliation(s)
- Jenny V Lockard
- Department of Chemistry and Biochemistry, University of California-Los Angeles, CA 90095, USA
| | | | | | | | | | | | | |
Collapse
|
8
|
Knippenberg S, François JP, Deleuze MS. Green's function study of the one-electron and shake-up ionization spectra of unsaturated hydrocarbon cage compounds. J Comput Chem 2006; 27:1703-22. [PMID: 16903000 DOI: 10.1002/jcc.20461] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The valence one-electron and shake-up ionization spectra of stella-2,6-diene, stella-2,6-dione, bicyclo-[2.2.2]-octane-2,5-dione, and bicyclo-[2.2.1]-heptane-2,5-dione have been exhaustively studied, up to the double ionization threshold and beyond, by means of one-particle Green's function theory. This study is based on calculations employing the outer-valence Green's function and the third-order algebraic diagrammatic construction schemes, along with a variety of basis sets. A comparison is made with available ultraviolet (He I) photoelectron and (e, 2e) electron-impact ionization spectra, with main focus on the identification of spectral fingerprints for cyclic strains and through-bond pi-conjugation. As a byproduct, our results demonstrate that it is impossible to reliably assign complex (e, 2e) ionization spectra by resorting only to Hartree-Fock or Kohn-Sham orbital energies and to the related electron momentum distributions.
Collapse
Affiliation(s)
- S Knippenberg
- Group of Theoretical Chemistry, Department SBG, Hasselt University, Agoralaan, Gebouw D, B-3590 Diepenbeek, Belgium
| | | | | |
Collapse
|
9
|
Alabugin IV, Manoharan M. Rehybridization as a general mechanism for maximizing chemical and supramolecular bonding and a driving force for chemical reactions. J Comput Chem 2006; 28:373-90. [PMID: 17143865 DOI: 10.1002/jcc.20524] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Dynamic variations in hybridization patterns (rehybridization) were analyzed at B3LYP/6-31G** and MP2/6-31+G* levels. Computations clearly illustrate the generality of rehybridization in a variety of chemical phenomena, which involve structural reorganization in hydrogen-bonded complexes, nonhyperconjugative stereoelectronic effects in saturated heterocycles, Mills-Nixon effect, and contrasting substituent effects in cycloaromatization reactions.
Collapse
Affiliation(s)
- Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA.
| | | |
Collapse
|
10
|
Geuenich D, Hess K, Köhler F, Herges R. Anisotropy of the induced current density (ACID), a general method to quantify and visualize electronic delocalization. Chem Rev 2005; 105:3758-72. [PMID: 16218566 DOI: 10.1021/cr0300901] [Citation(s) in RCA: 980] [Impact Index Per Article: 51.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel Geuenich
- Institut für Organische Chemie, Universität Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany
| | | | | | | |
Collapse
|
11
|
Lockard JV, Zink JI, Trieber Ii DA, Konradsson AE, Weaver MN, Nelsen SF. Excited-State Mixed Valence in a Diphenyl Hydrazine Cation: Spectroscopic Consequences of Coupling and Transition Dipole Moment Orientation. J Phys Chem A 2005; 109:1205-15. [PMID: 16833431 DOI: 10.1021/jp044750x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A quantitative model of mixed-valence excited-state spectroscopy is developed and applied to 2,3-diphenyl-2,3-diazabicyclo[2.2.2]octane. The lowest-energy excited state of this molecule arises from a transition from the ground state, where the charge is located on the hydrazine bridge, to an excited state where the charge is associated with one phenyl group or the other. Coupling splits the absorption band into two components with the lower-energy component being the most intense. The sign of the coupling, derived by using a neighboring orbital model, is positive. The transition dipole moments consist of parallel and antiparallel vector components, and selection rules for each are derived. Bandwidths are caused by progressions in totally symmetric modes determined from resonance Raman spectroscopic analysis. The absorption, emission, and Raman spectra are fit simultaneously with one parameter set.
Collapse
Affiliation(s)
- Jenny V Lockard
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | | | | | | | | | | |
Collapse
|
12
|
Wang F, Brunger MJ, McCarthy IE, Winkler DA. Exploring the electronic structure of 2,6-stelladione from momentum space I: the p-dominant molecular orbitals in the outer valence shell. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.09.151] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
13
|
Synthesis and anomalous structure–reactivity relationship of 8,11-dichloro[5]metacyclophan-3-one. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00239-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
14
|
Long-range sigma-pi interactions in tetrahydro-4H-thiopyran end-capped oligo(cyclohexylidenes). Photo-electron spectroscopy, ab initio SCF MO calculations, and natural bond orbital analyses. J Org Chem 2000; 65:4584-92. [PMID: 10959863 DOI: 10.1021/jo000199y] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Long-range sigma-pi interactions in tetrahydro4H-thiopyran end-capped oligo(cyclohexylidenes) were identified by He(I) photoelectron spectroscopy (PES) and ab initio RHF/6-31G* calculations. The vertical ionization energies Ivj of the highest occupied molecular orbitals (MO's) were assigned using Koopmans' theorem (Iv,j = -epsilonj) and by correlation with the ionizations of related reference compounds. The experimental (PES) and theoretical (RHF/6-31G*) results are in good agreement. For tercyclohexylidene derivatives which contain two nonconjugated pi-bonds splittings deltaIv,j of the pi-bands in the range from approximately 0.5 to 0.7 eV (delta-epsilonj approximately 0.6 to 0.9 eV). For the bi- and tercyclohexylidene compounds containing two sulfur atoms at their alpha- and omega-end positions the pi-type sulfur lone pair bands [Lppi(S)] split significantly by deltaIvj approximately 0.3 to 0.4 eV (delta-epsilonj approximately 0.3 to 0.4 eV), i.e. sigma-pi interactions over distances of ca. 8 and 12 A, respectively, occur. The magnitude of the interactions and the observed splittings are independent of the anti and syn conformations of the oligo(cyclohexylidene) hydrocarbon skeletons. RHF/6-31G* Natural Bond Orbital analyses reveal that the Hax-C-C-Hax precanonical MO's (PCMO's) centered on the cyclohexyl-type rings are paramount for the relay of the through-bond sigma-pi interactions; no through-space sigma-pi interactions were identified.
Collapse
|
15
|
Marsman A, Havenith R, Bethke S, Jenneskens L, Gleiter R, Lenthe J. Through-Bond Orbital Coupling in End-Functionalized Bicyclohexylidenes − Photoelectron Spectroscopy and Ab initio SCF−MO Calculations. European J Org Chem 2000. [DOI: 10.1002/1099-0690(200007)2000:14<2629::aid-ejoc2629>3.0.co;2-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
16
|
Affiliation(s)
- Peter F. H. Schwab
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850
| | | | | |
Collapse
|
17
|
|
18
|
|
19
|
Lange H, Gleiter R, Fritzsche G. Linear and Angular Interactions in Distellenes: Photoelectron Spectra and Ab Initio SCFMO Studies. J Am Chem Soc 1998. [DOI: 10.1021/ja980559n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Holger Lange
- Contribution from the Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Rolf Gleiter
- Contribution from the Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Gerd Fritzsche
- Contribution from the Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| |
Collapse
|
20
|
Gleiter R, Gaa B, Sigwart C, Lange H, Borzyk O, Rominger F, Irngartinger H, Oeser T. Preparation and Properties of Stelladiones. European J Org Chem 1998. [DOI: 10.1002/(sici)1099-0690(199801)1998:1<171::aid-ejoc171>3.0.co;2-m] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
21
|
Welsh WJ, Lin Y. Discussion of the catalytic pathway of cysteine proteases based on AM1 calculations. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0166-1280(97)00025-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
22
|
Winkler U, Schieck M, Pritzkow H, Driess M, Hyla-Kryspin I, Lange H, Gleiter R. Through-Bond Interactions in Silicon–Phosphorus and Silicon–Arsenic Compounds: A Facile Synthesis of Dodecamethyl-2,3,5,6,7,8-hexasila-1λ3,4λ3-diphosphabicyclo[2.2.2]octane, Its Arsenic Analogue, and Related Compounds. Chemistry 1997. [DOI: 10.1002/chem.19970030607] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|