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Vitanov NV, Drewsen M. Highly Efficient Detection and Separation of Chiral Molecules through Shortcuts to Adiabaticity. PHYSICAL REVIEW LETTERS 2019; 122:173202. [PMID: 31107075 DOI: 10.1103/physrevlett.122.173202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Indexed: 06/09/2023]
Abstract
A highly efficient method for optical or microwave detection and separation of left- and right-handed chiral molecules is proposed. The method utilizes a closed-loop three-state system in which the population dynamics depends on the phases of the three couplings. Because of the different signs of the coupling between two of the states for the opposite chiralities the population dynamics is chirality dependent. By using the "shortcuts to adiabaticity" concept applied to the stimulated Raman adiabatic passage technique, one can achieve 100% contrast between the two enantiomers in the population of a particular state. It can be probed by light-induced fluorescence for large ensembles or through resonantly enhanced multiphoton ionization for single molecules.
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Affiliation(s)
- Nikolay V Vitanov
- Department of Physics, St. Kliment Ohridski University of Sofia, James Bourchier 5 blvd, BG-1164 Sofia, Bulgaria
| | - Michael Drewsen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
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Garner MH, Hoffmann R, Rettrup S, Solomon GC. Coarctate and Möbius: The Helical Orbitals of Allene and Other Cumulenes. ACS CENTRAL SCIENCE 2018; 4:688-700. [PMID: 29974064 PMCID: PMC6026781 DOI: 10.1021/acscentsci.8b00086] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Indexed: 05/24/2023]
Abstract
As brought to the attention of the community by Hendon et al. and noted by previous workers, the π orbitals of the equilibrium geometry odd-carbon (even number of double bonds = n) [n]cumulenes may be written in either rectilinear or helical form. We trace the origins and detailed composition of the helical orbitals of cumulenes, which emerge in the simplest Hückel model and are not much modified in advanced computations. For the α,ω-disubstituted even [n]cumulenes, the helical representation is obligatory as the symmetry is reduced from D2d to C2. A relationship is apparent between these helical orbitals of the even [n]cumulenes, seen as a Herges coarctate system, and the corresponding Möbius cyclic polyene orbitals. The twist of the orbitals varies in interesting ways along the helix, and so does the contribution of the component atomic orbitals. Though the electronic structures of even [n]cumulenes and Möbius cyclopolyenes are closely related, they differ for higher n in intriguing ways; these are linked to the constrained rotation of the basis orbitals along the helical twist itinerary. Relations are constructed between the level patterns of the π-systems of even [n]cumulenes and ideas of Hückel and Möbius aromaticity.
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Affiliation(s)
- Marc H. Garner
- Department of Chemistry and Nano-Science Center, University
of Copenhagen, Universitetsparken
5, DK-2100, Copenhagen
Ø, Denmark
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 4850, United
States
| | - Roald Hoffmann
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 4850, United
States
| | - Sten Rettrup
- Department of Chemistry and Nano-Science Center, University
of Copenhagen, Universitetsparken
5, DK-2100, Copenhagen
Ø, Denmark
| | - Gemma C. Solomon
- Department of Chemistry and Nano-Science Center, University
of Copenhagen, Universitetsparken
5, DK-2100, Copenhagen
Ø, Denmark
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Chang BY, Shin S, Engel V, Sola IR. Geometrical Optimization Approach to Isomerization: Models and Limitations. J Phys Chem A 2017; 121:8280-8287. [DOI: 10.1021/acs.jpca.7b08767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bo Y. Chang
- School
of Chemistry (BK21), Seoul National University, Seoul 08826, Republic of Korea
| | - Seokmin Shin
- School
of Chemistry (BK21), Seoul National University, Seoul 08826, Republic of Korea
| | - Volker Engel
- Institut
für Physikalische und Theoretische Chemie, Universität Würzburg, 97074 Würzburg, Germany
| | - Ignacio R. Sola
- Departamento
de Química Física I, Universidad Complutense, 28040 Madrid, Spain
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Chiroptical properties and the racemization of pyrene and tetrathiafulvalene-substituted allene: substitution and solvent effects on racemization in tetrathiafulvalenylallene. Molecules 2014; 19:2829-41. [PMID: 24599123 PMCID: PMC6271782 DOI: 10.3390/molecules19032829] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/21/2014] [Accepted: 02/23/2014] [Indexed: 11/16/2022] Open
Abstract
Dissymmetric 1,3-diphenylallene derivative 3 connected with 4,5-bis(methyl-thio)tetrathiafulvalenyl and 1-pyrenyl substituents was prepared and characterized. The molecular structure was determined by X-ray crystallographic analysis. Optical resolution was accomplished using a recycling chiral HPLC, and its chiroptical properties were examined with optical rotation and electronic circular dichroism (ECD) spectra. The title compound underwent photoracemization under daylight. This behavior was investigated in various solvents and compared with that of 1,3-bis(tetrathiafulvalenyl)allene (bis-TTF-allene) derivative 2. The first-order rate plot of the intensity of the ECD spectra at a given time interval gave the rate of racemization. Mild racemization was observed in polar solvents, whereas a relatively fast rate was obtained in less polar solvents. In addition, the TTF groups of the allene also accelerate the racemization rate. These results suggest that the racemization mechanism occurs via a non-polar diradical structure.
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Gronert S, Keeffe JR. The Protonation of Allene and Some Heteroallenes, a Computational Study. J Org Chem 2007; 72:6343-52. [PMID: 17655254 DOI: 10.1021/jo0704107] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protonation of allene and seven heteroallenes, X = Y = Z, at the terminal and central positions has been studied computationally at the MP2/6-311+G**, B3LYP/6-31+G**, and G3 levels. In all but one case protonation at a terminal position is preferred thermodynamically. The exception is allene, where protonation at C2 giving allyl cation prevails by about 10 kcal/mol over end-protonation, which gives the 2-propenyl cation. In the heteroallenes, protonation at a terminal carbon is strongly favored, activated by electron donation from the other terminal atom. Transition states for identity proton-transfer reactions were found for 10 of the "end-to-end" proton transfers. When the transfer termini are heteroatoms these processes are barrier free. We found no first-order saddle point structures for "center-to-center" proton transfers. An estimate of DeltaH++ for an identity center-to-center proton transfer could be made only for the reaction between the allyl cation and allene; it is approximately 22 kcal/mol higher than DeltaH++ for the end-to-end proton transfer between the 2-propenyl cation and allene. First-order saddle points for the proton transfer from H3S+ to both C1 and C2 of allene were found. The difference in activation enthalpies is 9.9 kcal/mol favoring protonation at C1 in spite of the thermodynamic disadvantage. We infer that protonation of X = Y = Z at central atoms passes through transition states much like primary carbenium (nitrenium, oxenium) cations, poorly conjugated with the attached vinylic or heterovinylic group. Several other processes following upon center protonation were studied and are discussed in the text, special attention being given to comparison of open and cyclic isomers.
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Affiliation(s)
- Scott Gronert
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, USA.
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Gerbasi D, Shapiro M, Brumer P. Theory of “laser distillation” of enantiomers: Purification of a racemic mixture of randomly oriented dimethylallene in a collisional environment. J Chem Phys 2006; 124:74315. [PMID: 16497044 DOI: 10.1063/1.2171968] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Enantiomeric control of 1,3 dimethylallene in a collisional environment is examined. Specifically, our previous "laser distillation" scenario wherein three perpendicular linearly polarized light fields are applied to excite a set of vib-rotational eigenstates of a randomly oriented sample is considered. The addition of internal conversion, dissociation, decoherence, and collisional relaxation mimics experimental conditions and molecular decay processes. Of greatest relevance is internal conversion which, in the case of dimethylallene, is followed by molecular dissociation. For various rates of internal conversion, enantiomeric control is maintained in this scenario by a delicate balance between collisional relaxation of excited dimethylallene that enhances control and collisional dephasing, which diminishes control.
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Affiliation(s)
- David Gerbasi
- Center for Quantum Information and Quantum Control, University of Toronto, Ontario, Canada
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Rousseau R, Mazzarello R, Scandolo S. An Effective Pseudopotential for Modeling Gold Surface Slabs for Ab Initio Simulations. Chemphyschem 2005; 6:1756-60. [PMID: 16144002 DOI: 10.1002/cphc.200400615] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Roger Rousseau
- International School For Advanced Studies (ISAS/SISSA), Via Beirut 4, 34014 Trieste, Italy.
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Gerbasi D, Brumer P, Thanopulos I, Kral P, Shapiro M. Theory of the two step enantiomeric purification of 1,3 dimethylallene. J Chem Phys 2004; 120:11557-63. [PMID: 15268190 DOI: 10.1063/1.1753552] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An application of a recently proposed [P. Kral et al., Phys. Rev. Lett. 90, 033001 (2003)] two step optical control scenario to the purification of a racemic mixture of 1,3 dimethylallene is presented. Both steps combine adiabatic and diabatic passage phenomena. In the first step, three laser pulses of mutually perpendicular linear polarizations, applied in a "cyclic adiabatic passage" scheme, are shown to be able to distinguish between the L and D enantiomers due to their difference in matter-radiation phase. In the second step, which immediately follows the first, a sequence of pulses is used to convert one enantiomer to its mirror-imaged form. This scenario, which only negligibly populates the first excited electronic state, proves extremely useful for systems such as dimethylallene, which can suffer losses from dissociation and internal conversion upon electronic excitation. We computationally observe conversion of a racemic mixture of dimethylallene to a sample containing approximately 95% of the enantiomer of choice.
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Affiliation(s)
- David Gerbasi
- Chemical Physics Theory Group, Department of Chemistry, The University of Toronto, 80 St. George Street, Toronto, M5S3H6, Canada
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Frishman E, Shapiro M, Gerbasi D, Brumer P. Enantiomeric purification of nonpolarized racemic mixtures using coherent light. J Chem Phys 2003. [DOI: 10.1063/1.1603732] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Brumer Y, Shapiro M, Brumer P, Baldridge KK. Controlled Alcohol−Ketone Interconversion by Dihydrogen Transfer: An ab Initio Study of the Methanol−Formaldehyde Complex. J Phys Chem A 2002. [DOI: 10.1021/jp020689p] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yisroel Brumer
- Chemical Physics Department, The Weizmann Institute of Science, Rehovot, Israel 76100
| | - Moshe Shapiro
- Chemical Physics Department, The Weizmann Institute of Science, Rehovot, Israel 76100
| | - Paul Brumer
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Canada M5S 3H6
| | - Kim K. Baldridge
- University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0505
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