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Balaban AT, Young DC, Plavec J, Pečnik K, Pompe M, Dahl JE, Carlson RMK. NMR spectral properties of the tetramantanes - nanometer-sized diamondoids. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:1003-1018. [PMID: 26286373 DOI: 10.1002/mrc.4289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 06/08/2015] [Accepted: 06/12/2015] [Indexed: 06/04/2023]
Abstract
Tetramantanes, and all diamondoid hydrocarbons, possess carbon frameworks that are superimposable upon the cubic diamond lattice. This characteristic is invaluable in assigning their (1)H and (13)C NMR spectra because it translates into repeating structural features, such as diamond-cage isobutyl moieties with distinctively complex methine to methylene signatures in COSY and HMBC data, connected to variable, but systematic linkages of methine and quaternary carbons. In all tetramantane C22H28 isomers, diamond-lattice structures result in long-range (4)JHH, W-coupling in COSY data, except where negated by symmetry; there are two highly symmetrical and one chiral tetramantane (showing seven (4)JHH). Isobutyl-cage methines of lower diamondoids and tetramantanes are the most shielded resonances in their (13)C spectra (<29.5 ppm). The isobutyl methylenes are bonded to additional methines and at least one quaternary carbon in the tetramantanes. W-couplings between these methines and methylenes clarify spin-network interconnections and detailed surface hydrogen stereochemistry. Vicinal couplings of the isobutyl methylenes reveal positions of the quaternary carbons: HMBC data then tie the more remote spin systems together. Diamondoid (13) C NMR chemical shifts are largely determined by α and β effects, however γ-shielding effects are important in [123]tetramantane. (1)H NMR chemical shifts generally correlate with numbers of 1,3-diaxial H-H interactions. Tight van der Waals contacts within [123]tetramantane's molecular groove, however, form improper hydrogen bonds, deshielding hydrogen nuclei inside the groove, while shielding those outside, indicated by Δδ of 1.47 ppm for geminal hydrogens bonded to C-3,21. These findings should be valuable in future NMR studies of diamondoids/nanodiamonds of increasing size.
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Affiliation(s)
- Alexandru T Balaban
- Texas A&M University at Galveston, Department of Marine Sciences, 200 Seawolf Parkway, Galveston, TX, 77553, USA
| | | | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Ljubljana, Slovenia
| | - Klemen Pečnik
- Slovenian NMR Centre, National Institute of Chemistry, Ljubljana, Slovenia
| | - Matevž Pompe
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, Aškerčeva 5, 1000, Ljubljana, Slovenia
| | - Jeremy E Dahl
- Stanford Institute for Materials and Energy Sciences, Stanford University, 476 Lomita Mall, Stanford, CA, 94305, USA
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Robert M K Carlson
- Stanford Institute for Materials and Energy Sciences, Stanford University, 476 Lomita Mall, Stanford, CA, 94305, USA
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
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Fokin AA, Chernish LV, Gunchenko PA, Tikhonchuk EY, Hausmann H, Serafin M, Dahl JEP, Carlson RMK, Schreiner PR. Stable alkanes containing very long carbon-carbon bonds. J Am Chem Soc 2012; 134:13641-50. [PMID: 22835264 DOI: 10.1021/ja302258q] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The metal-induced coupling of tertiary diamondoid bromides gave highly sterically congested hydrocarbon (hetero)dimers with exceptionally long central C-C bonds of up to 1.71 Å in 2-(1-diamantyl)[121]tetramantane. Yet, these dimers are thermally very stable even at temperatures above 200 °C, which is not in line with common C-C bond length versus bond strengths correlations. We suggest that the extraordinary stabilization arises from numerous intramolecular van der Waals attractions between the neighboring H-terminated diamond-like surfaces. The C-C bond rotational dynamics of 1-(1-adamantyl)diamantane, 1-(1-diamantyl)diamantane, 2-(1-adamantyl)triamantane, 2-(1-diamantyl)triamantane, and 2-(1-diamantyl)[121]tetramantane were studied through variable-temperature (1)H- and (13)C NMR spectroscopies. The shapes of the inward (endo) CH surfaces determine the dynamic behavior, changing the central C-C bond rotation barriers from 7 to 33 kcal mol(-1). We probe the ability of popular density functional theory (DFT) approaches (including BLYP, B3LYP, B98, B3LYP-Dn, B97D, B3PW91, BHandHLYP, B3P86, PBE1PBE, wB97XD, and M06-2X) with 6-31G(d,p) and cc-pVDZ basis sets to describe such an unusual bonding situation. Only functionals accounting for dispersion are able to reproduce the experimental geometries, while most DFT functionals are able to reproduce the experimental rotational barriers due to error cancellations. Computations on larger diamondoids reveal that the interplay between the shapes and the sizes of the CH surfaces may even allow the preparation of open-shell alkyl radical dimers (and possibly polymers) that are strongly held together exclusively by dispersion forces.
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Affiliation(s)
- Andrey A Fokin
- Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine.
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Schreiner PR, Fokin AA, Reisenauer HP, Tkachenko BA, Vass E, Olmstead MM, Bläser D, Boese R, Dahl JEP, Carlson RMK. [123]Tetramantane: Parent of a New Family of σ-Helicenes. J Am Chem Soc 2009; 131:11292-3. [DOI: 10.1021/ja904527g] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter R. Schreiner
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Andrey A. Fokin
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Hans Peter Reisenauer
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Boryslav A. Tkachenko
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Elemér Vass
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Marilyn M. Olmstead
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Dieter Bläser
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Roland Boese
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Jeremy E. P. Dahl
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
| | - Robert M. K. Carlson
- Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany, Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary, Department of Chemistry, University of California, Davis, California 95616, Institut für Anorganische Chemie, Universität Essen-Duisburg, Universitätsstr. 5, 45117 Essen, Germany, and MolecularDiamond Technologies, Chevron
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