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Lin WT, Shih YJ, Hsu TJ, Hu WP. Noble Gas in a Ring. Molecules 2021; 26:molecules26154677. [PMID: 34361829 PMCID: PMC8347956 DOI: 10.3390/molecules26154677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 11/23/2022] Open
Abstract
We have designed a new type of molecule with a noble gas (Ng = Kr and Xe) atom in a six-membered ring. Their structures and stability have been studied by density functional theory and by correlated electronic structure calculations. The results showed that the six-membered ring is planar with very short Ng–O and Ng–N polar covalent bonds. The calculated energy barriers for all the unimolecular dissociation pathways are higher than 20 and 35 kcal/mol for Ng = Kr and Xe, respectively. The current study suggests that these molecules and their derivatives might be synthesized and observable at cryogenic conditions.
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Affiliation(s)
- Wei-Te Lin
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan; (W.-T.L.); (Y.-J.S.)
| | - Ya-Jyun Shih
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan; (W.-T.L.); (Y.-J.S.)
| | - Tzu-Jeng Hsu
- Department of Mechanical Engineering, Chung Yuan Christian University, Chung-Li 320, Taiwan;
| | - Wei-Ping Hu
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan; (W.-T.L.); (Y.-J.S.)
- Correspondence:
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Zhang G, Su Y, Zou X, Fu L, Song J, Chen D, Sun C. Charge-Shift Bonding in Xenon Hydrides: An NBO/NRT Investigation on HXeY···HX (Y = Cl, Br, I; X = OH, Cl, Br, I, CCH, CN) via H-Xe Blue-Shift Phenomena. Front Chem 2020; 8:277. [PMID: 32391318 PMCID: PMC7191121 DOI: 10.3389/fchem.2020.00277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/23/2020] [Indexed: 11/13/2022] Open
Abstract
Noble-gas bonding represents curiosity. Some xenon hydrides, such as HXeY (Y = Cl, Br, I) and their hydrogen-bonded complexes HXeY···HX (Y = Cl, Br, I; X = OH, Cl, Br, I, CN, CCH), have been identified in matrixes by observing H-Xe frequencies or its monomer-to-complex blue shifts. However, the H-Xe bonding in HXeY is not yet completely understood. Previous theoretical studies provide two answers. The first one holds that it is a classical covalent bond, based on a single ionic structure H-Xe+ Y-. The second one holds that it is resonance bonding between H-Xe+ Y- and H- Xe+-Y. This study investigates the H-Xe bonding, via unusual blue-shifted phenomena, combined with some NBO/NRT calculations for chosen hydrogen-bonded complexes HXeY···HX (Y = Cl, Br, I; X = OH, Cl, Br, I, CN, CCH). This study provides new insights into the H-Xe bonding in HXeY. The H-Xe bond in HXeY is not a classical covalent bond. It is a charge-shift (CS) bond, a new class of electron-pair bonds, which is proposed by Shaik and Hiberty et al. The unusual blue shift in studied hydrogen-bonded complexes is its H-Xe CS bonding character in IR spectroscopy. It is expected that these studies on the H-Xe bonding and its IR spectroscopic property might assist the chemical community in accepting this new-class electron-pair bond concept.
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Affiliation(s)
- Guiqiu Zhang
- Key Laboratory of Molecular and Nano Probes, College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Ministry of Education, Shandong Normal University, Jinan, China
| | | | | | | | | | | | - Chuanzhi Sun
- Key Laboratory of Molecular and Nano Probes, College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Ministry of Education, Shandong Normal University, Jinan, China
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Jiao Y, Weinhold F. What Is the Nature of Supramolecular Bonding? Comprehensive NBO/NRT Picture of Halogen and Pnicogen Bonding in RPH 2···IF/FI Complexes (R = CH 3, OH, CF 3, CN, NO 2). Molecules 2019; 24:molecules24112090. [PMID: 31159347 PMCID: PMC6600247 DOI: 10.3390/molecules24112090] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 05/28/2019] [Accepted: 05/30/2019] [Indexed: 11/16/2022] Open
Abstract
We employ a variety of natural bond orbital (NBO) and natural resonance theory (NRT) tools to comprehensively investigate the nature of halogen and pnicogen bonding interactions in RPH2···IF/FI binary complexes (R = CH3, OH, CF3, CN, and NO2) and the tuning effects of R-substituents. Though such interactions are commonly attributed to “sigma-hole”-type electrostatic effects, we show that they exhibit profound similarities and analogies to the resonance-type 3-center, 4-electron (3c/4e) donor-acceptor interactions of hydrogen bonding, where classical-type “electrostatics” are known to play only a secondary modulating role. The general 3c/4e resonance perspective corresponds to a continuous range of interatomic A···B bond orders (bAB), spanning both the stronger “covalent” interactions of the molecular domain (say, bAB ≥ ½) and the weaker interactions (bAB ˂ ½, often misleadingly termed “noncovalent”) that underlie supramolecular complexation phenomena. We show how a unified NBO/NRT-based description of hydrogen, halogen, pnicogen, and related bonding yields an improved predictive utility and intuitive understanding of empirical trends in binding energies, structural geometry, and other measurable properties that are expected to be manifested in all such supramolecular interaction phenomena.
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Affiliation(s)
- Yinchun Jiao
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecules, Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China.
| | - Frank Weinhold
- Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Abstract
What is now called "resonance theory" has a long and conflicted history. We first sketch the early roots of resonance theory, its heritage of diverse physics and chemistry conceptions, and its subsequent rise to reigning chemical bonding paradigm of the mid-20th century. We then outline the alternative "natural" pathway to localized Lewis- and resonance-structural conceptions that was initiated in the 1950s, given semi-empirical formulation in the 1970s, recast in ab initio form in the 1980s, and successfully generalized to multi-structural "natural resonance theory" (NRT) form in the 1990s. Although earlier numerical applications were often frustrated by the ineptness of then-available numerical solvers, the NRT variational problem was recently shown to be amenable to highly efficient convex programming methods that yield provably optimal resonance weightings at a small fraction of previous computational costs. Such convexity-based algorithms now allow a full "reboot" of NRT methodology for tackling a broad range of chemical applications, including the many familiar resonance phenomena of organic and biochemistry as well as the still broader range of resonance attraction effects in the inorganic domain. We illustrate these advances for prototype chemical applications, including (i) stable near-equilibrium species, where resonance mixing typically provides only small corrections to a dominant Lewis-structural picture, (ii) reactive transition-state species, where strong resonance mixing of reactant and product bonding patterns is inherent, (iii) coordinative and related supramolecular interactions of the inorganic domain, where sub-integer resonance bond orders are the essential origin of intermolecular attraction, and (iv) exotic long-bonding and metallic delocalization phenomena, where no single "parent" Lewis-structural pattern gains pre-eminent weighting in the overall resonance hybrid.
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Affiliation(s)
- Eric D Glendening
- Department of Chemistry and Physics , Indiana State University , Terre Haute , Indiana 47809 , United States
| | - Clark R Landis
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Frank Weinhold
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
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Resonance bonding in XNgY (X = F, Cl, Br, I; Ng = Kr or Xe; Y = CN or NC) molecules: an NBO/NRT investigation. J Mol Model 2018; 24:129. [PMID: 29736860 DOI: 10.1007/s00894-018-3665-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
Several noble-gas-containing molecules XNgY were observed experimentally. However, the bonding in such systems is still not understood. Using natural bond orbital and natural resonance theory (NBO/NRT) methods, the present work investigated bonding of the title molecules. The results show that each of the studied XNgY molecules should be better described as a resonance hybrid of ω-bonding and [Formula: see text]-type long-bonding structures: X:- Ng+ - Y, X - Ng+: Y-, and X^Y. The ω-bonding and long-bonding make competing contributions to the composite resonance hybrid due to the accurately preserved bond order conservation principle. We find that the resonance bonding is highly tunable for these noble-gas-containing molecules due to its dependence on the nature of the halogen X or the central noble-gas atoms Ng. When the molecule XNgY consists of a relatively lighter Ng atom, a relatively low-electronegative X atom, and the CN fragment rather than NC, the long-bonding structure X^Y tends to be highlighted. In contrast, the heavy Ng atom and high-electronegative X atom will enhance the ω-bonding structure. Overall, the present work provides electronic principles and chemical insights that help understand the bonding in these XNgY species.
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Zhang G, Song J, Fu L, Tang K, Su Y, Chen D. Understanding and modulating the high-energy properties of noble-gas hydrides from their long-bonding: an NBO/NRT investigation on HNgCO +/CS +/OSi + and HNgCN/NC (Ng = He, Ar, Kr, Xe, Rn) molecules. Phys Chem Chem Phys 2018; 20:10231-10239. [PMID: 29611602 DOI: 10.1039/c8cp00306h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The noble-gas hydrides, HNgX (X is an electronegative atom or fragment), represent potential high-energy materials because their two-body decomposition process, HNgX → Ng + HX, is strongly exoergic. Our previous studies have shown that each member of the HNgX (X = halogen atom or CN/NC fragment) molecules is composed of three leading resonance structures: two ω-bonding structures (H-Ng+ :X- and H:- Ng+-X) and one long-bonding structure (H∧X). The last one paints a novel [small sigma, Greek, circumflex]-type long-bonding picture. The present study focuses on the relationship between this novel bonding motif and the unusual energetic properties. We chose HNgCO+/CS+/OSi+/CN/NC, with the formula HNgAB (Ng = He, Ar, Kr, Xe, Rn; AB = CO+/CS+/OSi+/CN/NC) as the research system. We first investigated the bonding of HNgCO+ and its analogous HNgCS+/OSi+ species using NBO/NRT methods, and quantitatively compared the bonding with that in HNgCN/NC molecules. NBO/NRT results showed that each of the HNgCO+/CS+/OSi+ molecules could be better represented as a resonance hybrid of ω-bonding and long-bonding structures, but the long-bonding is much weaker than that in HNgCN/NC molecules. Furthermore, we introduced the long-bonding concept into the rationalization of the high-energy properties, and found a good correlation between the highly exothermic two-body dissociation channel and the long-bond order, bH-A. We also found that the long-bond order is highly tunable for these noble-gas hydrides due to its dependence on the nature of the electronegative AB fragments or the central noble-gas atoms, Ng. On the basis of these results, we could optimize the energetic properties by changing the long-bonding motif of our studied molecules. Overall, this study shows that the long-bonding model provides an easy way to rationalize and modulate the unusual energy properties of noble-gas hydrides, and that it is helpful to predict some noble-gas hydrides as potential energetic materials.
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Affiliation(s)
- Guiqiu Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Wenhua East Road 88, Jinan, Shandong 250014, P. R. China.
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