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Qin L, Liu YQ, Liu R, Yang X, Cui ZH, Zhao L, Pan S, Fau S, Frenking G. Analysis of the Unusual Chemical Bonds and Dipole Moments of AeF - (Ae=Be-Ba): A Lesson in Covalent Bonding. Chemistry 2024; 30:e202304136. [PMID: 38206568 DOI: 10.1002/chem.202304136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/12/2024]
Abstract
Quantum chemical calculations of the anions AeF- (Ae=Be-Ba) have been carried out using ab initio methods at the CCSD(T)/def2-TZVPP level and density functional theory employing BP86 with various basis sets. The detailed bonding analyses using different charge- and energy partitioning methods show that the molecules possess three distinctively different dative bonds in the lighter species with Ae=Be, Mg and four dative bonds when Ae=Ca, Sr, Ba. The occupied 2p atomic orbitals (AOs) and to a lesser degree the occupied 2s AO of F- donate electronic charge into the vacant spx(σ) and p(π) orbitals of Be and Mg which leads to a triple bond Ae F-. The heavier Ae atoms Ca, Sr, Ba use their vacant (n-1)d AOs as acceptor orbitals which enables them to form a second σ donor bond with F- that leads to quadruply bonded Ae F- (Ae=Ca-Ba). The presentation of molecular orbitals or charge distribution using only one isodensity value may give misleading information about the overall nature of the orbital or charge distribution. Better insights are given by contour line diagrams. The ELF calculations provide monosynaptic and disynaptic basins of AeF- which nicely agree with the analysis of the occupied molecular orbitals and with the charge density difference maps. A particular feature of the covalent bonds in AeF- concerns the inductive interaction of F- with the soft valence electrons in the (n)s valence orbitals of Ae. The polarization of the (n)s2 electrons induces a (n)spx hybridized lone-pair orbital at atom Ae, which yields a large dipole moment with the negative end at Ae. The concomitant formation of a vacant (n)spx AO of atom Ae, which overlaps with the occupied 2p(σ) AO of F-, leads to a strong covalent σ bond.
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Affiliation(s)
- Lei Qin
- State Key Laboratory of Materials-Oriented Chemical Engineering, School of Chemistry and Molecular Engineering, Nanjing Tech University, 211816, Nanjing, China
| | - Yu-Qian Liu
- Institute of Atomic and Molecular Physics, Jilin University, 130023, Changchun, China
| | - Ruiqin Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, School of Chemistry and Molecular Engineering, Nanjing Tech University, 211816, Nanjing, China
| | - Xing Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, School of Chemistry and Molecular Engineering, Nanjing Tech University, 211816, Nanjing, China
| | - Zhong-Hua Cui
- Institute of Atomic and Molecular Physics, Jilin University, 130023, Changchun, China
| | - Lili Zhao
- State Key Laboratory of Materials-Oriented Chemical Engineering, School of Chemistry and Molecular Engineering, Nanjing Tech University, 211816, Nanjing, China
| | - Sudip Pan
- Institute of Atomic and Molecular Physics, Jilin University, 130023, Changchun, China
| | - Stefan Fau
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, D-35043, Marburg, Germany
| | - Gernot Frenking
- State Key Laboratory of Materials-Oriented Chemical Engineering, School of Chemistry and Molecular Engineering, Nanjing Tech University, 211816, Nanjing, China
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, D-35043, Marburg, Germany
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Brown OR, Hullender DA. Biological evolution requires an emergent, self-organizing principle. Prog Biophys Mol Biol 2023:S0079-6107(23)00058-5. [PMID: 37343790 DOI: 10.1016/j.pbiomolbio.2023.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/16/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023]
Abstract
In this perspective review, we assess fundamental flaws in Darwinian evolution, including its modern versions. Fixed mutations 'explain' microevolution but not macroevolution including speciation events and the origination of all the major body plans of the Cambrian explosion. Complex, multifactorial change is required for speciation events and inevitably requires self-organization beyond what is accomplished by known mechanisms. The assembly of ribosomes and ATP synthase are specific examples. We propose their origin is a model for what is unexplained in biological evolution. Probability of evolution is modeled in Section 9 and values are absurdly improbable. Speciation and higher taxonomic changes become exponentially less probable as the number of required, genetically-based events increase. Also, the power required of the proposed selection mechanism (survival of the fittest) is nil for any biological advance requiring multiple changes, because they regularly occur in multiple generations (different genomes) and would not be selectively conserved by the concept survival of the fittest (a concept ultimately centered on the individual). Thus, survival of the fittest cannot 'explain' the origin of the millions of current and extinct species. We also focus on the inadequacies of laboratory chemistry to explain the complex, required biological self-organization seen in cells. We propose that a 'bioelectromagnetic' field/principle emerges in living cells. Synthesis by self-organization of massive molecular complexes involves biochemical responses to this emergent field/principle. There are ramifications for philosophy, science, and religion. Physics and mathematics must be more strongly integrated with biology and integration should receive dedicated funding with special emphasis for medical applications; treatment of cancer and genetic diseases are examples.
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Affiliation(s)
- Olen R Brown
- Emeritus of Biomedical Sciences, at the University of Missouri, Columbia, MO, USA.
| | - David A Hullender
- Mechanical and Aerospace Engineering at the University of Texas at Arlington, USA
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Freindorf M, Delgado AAA, Kraka E. CO bonding in hexa‐ and pentacoordinate carboxy‐neuroglobin: A quantum mechanics/molecular mechanics and local vibrational mode study. J Comput Chem 2022. [DOI: 10.1002/jcc.26973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marek Freindorf
- Department of Chemistry Southern Methodist University Dallas Texas USA
| | | | - Elfi Kraka
- Department of Chemistry Southern Methodist University Dallas Texas USA
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Anila S, Suresh CH, Schaefer HF. Demarcating Noncovalent and Covalent Bond Territories: Imine-CO 2 Complexes and Cooperative CO 2 Capture. J Phys Chem A 2022; 126:4952-4961. [PMID: 35862882 DOI: 10.1021/acs.jpca.2c03221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chemical bond territory is rich with covalently bonded molecules wherein a strong bond is formed by equal or unequal sharing of a quantum of electrons. The noncovalent version of the bonding scenarios expands the chemical bonding territory to a weak domain wherein the interplay of electrostatic and π-effects, dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole interactions, and hydrophobic effects occur. Here we study both the covalent and noncovalent interactive behavior of cyclic and acyclic imine-based functional molecules (XN) with CO2. All parent XN systems preferred the formation of noncovalent (nc) complex XN···CO2, while more saturated such systems (XN') produced both nc and covalent (c) complexes XN'+-(CO2)-. In all such cases, crossover from an nc to c complex is clearly demarcated with the identification of a transition state (ts). The complexes XN'···CO2 and XN'+-(CO2)- are bond stretch isomers, and they define the weak and strong bonding territories, respectively, while the ts appears as the demarcation point of the two territories. Cluster formation of XN with CO2 reinforces the interaction between them, and all become covalent clusters of general formula (XN+-(CO2)-)n. The positive cooperativity associated with the NH···OC hydrogen bond formation between any two XN'+-(CO2)- units strengthened the N-C coordinate covalent bond and led to massive stabilization of the cluster. For instance, the stabilizing interaction between the XN unit with CO2 is increased from 2-7 kcal/mol range in a monomer complex to 14-31 kcal/mol range for the octamer cluster (XN'+-(CO2)-)8. The cooperativity effect compensates for the large reduction in the entropy of cluster formation. Several imine systems showed the exergonic formation of the cluster and are predicted as potential candidates for CO2 capture and conversion.
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Affiliation(s)
- Sebastian Anila
- Chemical Sciences and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Cherumuttathu H Suresh
- Chemical Sciences and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Henry F Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens 30602, Georgia, United States
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Lo R, Manna D, Lamanec M, Dračínský M, Bouř P, Wu T, Bastien G, Kaleta J, Miriyala VM, Špirko V, Mašínová A, Nachtigallová D, Hobza P. The stability of covalent dative bond significantly increases with increasing solvent polarity. Nat Commun 2022; 13:2107. [PMID: 35440662 DOI: 10.1038/s41467-022-29806-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 03/29/2022] [Indexed: 11/29/2022] Open
Abstract
It is generally expected that a solvent has only marginal effect on the stability of a covalent bond. In this work, we present a combined computational and experimental study showing a surprising stabilization of the covalent/dative bond in Me3NBH3 complex with increasing solvent polarity. The results show that for a given complex, its stability correlates with the strength of the bond. Notably, the trends in calculated changes of binding (free) energies, observed with increasing solvent polarity, match the differences in the solvation energies (ΔEsolv) of the complex and isolated fragments. Furthermore, the studies performed on the set of the dative complexes, with different atoms involved in the bond, show a linear correlation between the changes of binding free energies and ΔEsolv. The observed data indicate that the ionic part of the combined ionic-covalent character of the bond is responsible for the stabilizing effects of solvents. Non covalent complexes are often considerably destabilized in the solvent. Here the authors combine vibrational Raman and NMR spectroscopy with a coupled-cluster computational investigation to show that the solvent polarity enhance the complex stability of a Me3NBH3 complex.
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