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Colin-Molina A, Jellen MJ, Rodríguez-Hernández J, Cifuentes-Quintal ME, Barroso J, Toscano RA, Merino G, Rodríguez-Molina B. Hydrogen-Bonded Crystalline Molecular Machines with Ultrafast Rotation and Displacive Phase Transitions. Chemistry 2020; 26:11727-11733. [PMID: 32243632 DOI: 10.1002/chem.202001156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/02/2020] [Indexed: 01/28/2023]
Abstract
Two new crystalline rotors 1 and 2 assembled through N-H⋅⋅⋅N hydrogen bonds by using halogenated carbazole as stators and 1,4-diaza[2.2.2]bicyclooctane (DABCO) as the rotator, are described. The dynamic characterization through 1 H T1 relaxometry experiments indicate very low rotational activation barriers (Ea ) of 0.67 kcal mol-1 for 1 and 0.26 kcal mol-1 for 2, indicating that DABCO can reach a THz frequency at room temperature in the latter. These Ea values are supported by solid-state density functional theory computations. Interestingly, both supramolecular rotors show a phase transition between 298 and 250 K, revealed by differential scanning calorimetry and single-crystal X-ray diffraction. The subtle changes in the crystalline environment of these rotors that can alter the motion of an almost barrierless DABCO are discussed here.
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Affiliation(s)
- Abraham Colin-Molina
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, Ciudad de México, México
| | - Marcus J Jellen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA
| | - Joelis Rodríguez-Hernández
- Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna Hermosillo, No. 140, Saltillo, Coahuila, 25294, México
| | - Miguel Eduardo Cifuentes-Quintal
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310, Mérida, Yuc., México
| | - Jorge Barroso
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310, Mérida, Yuc., México
| | - Rubén A Toscano
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, Ciudad de México, México
| | - Gabriel Merino
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310, Mérida, Yuc., México
| | - Braulio Rodríguez-Molina
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, Ciudad de México, México
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Beckmann PA, McGhie AR, Rheingold AL, Sloan GJ, Szewczyk ST. Solid-Solid Phase Transitions and tert-Butyl and Methyl Group Rotation in an Organic Solid: X-ray Diffractometry, Differential Scanning Calorimetry, and Solid-State 1H Nuclear Spin Relaxation. J Phys Chem A 2017; 121:6220-6230. [PMID: 28742961 DOI: 10.1021/acs.jpca.7b06265] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Using solid-state 1H nuclear magnetic resonance (NMR) spin-lattice relaxation experiments, we have investigated the effects of several solid-solid phase transitions on tert-butyl and methyl group rotation in solid 1,3,5-tri-tert-butylbenzene. The goal is to relate the dynamics of the tert-butyl groups and their constituent methyl groups to properties of the solid determined using single-crystal X-ray diffraction and differential scanning calorimetry (DSC). On cooling, the DSC experiments see a first-order, solid-solid phase transition at either 268 or 155 K (but not both) depending on thermal history. The 155 K transition (on cooling) is identified by single-crystal X-ray diffraction to be one from a monoclinic phase (above 155 K), where the tert-butyl groups are disordered (that is, with a rotational 6-fold intermolecular potential dominating), to a triclinic phase (below 155 K), where the tert-butyl groups are ordered (that is, with a rotational 3-fold intermolecular potential dominating). This transition shows very different DSC scans when both a 4.7 mg polycrystalline sample and a 19 mg powder sample are used. The 1H spin-lattice relaxation experiments with a much larger 0.7 g sample are very complicated and, depending on thermal history, can show hysteresis effects over many hours and over very large temperature ranges. In the high-temperature monoclinic phase, the tert-butyl groups rotate with NMR activation energies (closely related to rotational barriers) in the 17-23 kJ mol-1 range, and the constituent methyl groups rotate with NMR activation energies in the 7-12 kJ mol-1 range. In the low-temperature triclinic phase, the rotations of the tert-butyl groups and their methyl groups in the aromatic plane are quenched (on the NMR time scale). The two out-of-plane methyl groups in the tert-butyl groups are rotating with activation energies in the 5-11 kJ mol-1 range.
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Affiliation(s)
- Peter A Beckmann
- Department of Physics, Bryn Mawr College , 101 North Merion Avenue, Bryn Mawr, Pennsylvania 19010-2899, United States
| | | | - Arnold L Rheingold
- Department of Chemistry and Biochemistry, University of California, San Diago , 5128 Urey Hall, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
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Beckmann PA, Moore CE, Rheingold AL. Methyl and t-butyl group rotation in a molecular solid: 1H NMR spin-lattice relaxation and X-ray diffraction. Phys Chem Chem Phys 2016; 18:1720-6. [DOI: 10.1039/c5cp04994f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report solid state 1H nuclear magnetic resonance spin-lattice relaxation experiments and X-ray diffractometry in 2-t-butyldimethylsilyloxy-6-bromonaphthalene.
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Affiliation(s)
| | - Curtis E. Moore
- Department of Chemistry and Biochemistry
- University of California
- La Jolla
- USA
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Wang X, Mallory FB, Mallory CW, Odhner HR, Beckmann PA. Solid state ¹H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: the relationship between structure and methyl group and t-butyl group rotation. J Chem Phys 2014; 140:194304. [PMID: 24852535 DOI: 10.1063/1.4874157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state (1)H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl group rotation in a central target molecule in the cluster with the activation energies determined from fitting the (1)H NMR spin-lattice relaxation data. We formulate a dynamical model for the superposition of t-butyl group rotation and the rotation of the t-butyl group's constituent methyl groups. The four compounds are 2,7-di-t-butylpyrene, 1,4-di-t-butylbenzene, 2,6-di-t-butylnaphthalene, and 3-t-butylchrysene. We comment on the unusual ground state orientation of the t-butyl groups in the crystal of the pyrene and we comment on the unusually high rotational barrier of these t-butyl groups.
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Affiliation(s)
- Xianlong Wang
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, 4 North Jianshe Rd., 2nd Section, Chengdu 610054, China
| | - Frank B Mallory
- Department of Chemistry, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899, USA
| | - Clelia W Mallory
- Department of Chemistry, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899, USA
| | - Hosanna R Odhner
- Department of Physics, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899, USA
| | - Peter A Beckmann
- Department of Physics, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899, USA
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Fahey DP, Dougherty WG, Kassel WS, Wang X, Beckmann PA. Nonexponential Solid State 1H and 19F Spin–Lattice Relaxation, Single-crystal X-ray Diffraction, and Isolated-Molecule and Cluster Electronic Structure Calculations in an Organic Solid: Coupled Methyl Group Rotation and Methoxy Group Libration in 4,4′-Dimethoxyoctafluorobiphenyl. J Phys Chem A 2012; 116:11946-56. [DOI: 10.1021/jp3075892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Donald P. Fahey
- Department of Physics, Bryn Mawr College, 101 North Merion Avenue, Bryn Mawr,
Pennsylvania 19010-2899, United States
| | - William G. Dougherty
- Department of Chemistry, Villanova University, 800 Lancaster Avenue, Villanova,
Pennsylvania 19085-1597, United States
| | - W. Scott Kassel
- Department of Chemistry, Villanova University, 800 Lancaster Avenue, Villanova,
Pennsylvania 19085-1597, United States
| | - Xianlong Wang
- School of Life Science and Technology, University of Electronic Science and Technology of China, 4 North Jianshe Road, Second Section, Chengdu, China 610054
| | - Peter A. Beckmann
- Department of Physics, Bryn Mawr College, 101 North Merion Avenue, Bryn Mawr,
Pennsylvania 19010-2899, United States
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Wang X, Rotkina L, Su H, Beckmann PA. Single-Crystal X-Ray Diffraction, Isolated-Molecule and Cluster Electronic Structure Calculations, and Scanning Electron Microscopy in an Organic solid: Models for Intramolecular Motion in 4,4′-Dimethoxybiphenyl. Chemphyschem 2012; 13:2082-9. [DOI: 10.1002/cphc.201101067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Indexed: 11/08/2022]
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Beckmann PA, Schneider E. Methyl group rotation,1H spin-lattice relaxation in an organic solid, and the analysis of nonexponential relaxation. J Chem Phys 2012; 136:054508. [DOI: 10.1063/1.3677183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Popa LC, Rheingold AL, Beckmann PA. A proton spin-lattice relaxation rate study of methyl and t-butyl group reorientation in the solid state. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2010; 38:31-35. [PMID: 20605083 DOI: 10.1016/j.ssnmr.2010.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 06/08/2010] [Accepted: 06/10/2010] [Indexed: 05/29/2023]
Abstract
We have measured the solid state nuclear magnetic resonance (NMR) 1H spin-lattice relaxation rate from 93 to 340 K at NMR frequencies of 8.5 and 53 MHz in 5-t-butyl-4-hydroxy-2-methylphenyl sulfide. We have also determined the molecular and crystal structures from X-ray diffraction experiments. The relaxation is caused by methyl and t-butyl group rotation modulating the spin-spin interactions and we relate the NMR dynamical parameters to the structure. A successful fit of the data requires that the 2-methyl groups are rotating fast (on the NMR time scale) even at the lowest temperatures employed. The rotational barrier for the two out-of-plane methyl groups in the t-butyl groups is 14.3+/-2.7 kJ mol(-1) and the rotational barrier for the t-butyl groups and their in-plane methyl groups is 24.0+/-4.6 kJ mol(-1). The uncertainties account for the uncertainties associated with the relationship between the observed NMR activation energy and a model-independent barrier, as well as the experimental uncertainties.
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Affiliation(s)
- Laura C Popa
- Department of Physics, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, PA 19010-2899, USA
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