Trigonal Bipyramidal and Related Molecules of the Main Group Elements: Investigation of Apparent Exceptions to the VSEPR Model through the Analysis of the Laplacian of the Electron Density

Gillespie, R. J.; Bytheway, Ian; DeWitte, Robert S.; Bader, R. F. W.

doi:10.1021/ic00088a011

Cited by 44 publications

(26 citation statements)

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“…Sulfur tetrafluoride has previously been analyzed using QTAIM by Gillespie et al at the HF/6-311G** level of theory. [27] The AIM results in this study are in good agreement with those reported previously,w here any deviations result from the difference in the level of theory used. The formation of the adducts is accompanied by ar eduction in the atomic basin chargeso ns ulfur (SF 4 2.648, SF 4 ·NC 5 H 5 2.548, SF 4 ·4-NC 5 H 4 (CH 3 ) 2.548, SF 4 ·2,6-NC 5 H 3 (CH 3 ) 2 2.600, SF 4 ·4-NC 5 H 4 N(CH 3 ) 2 2.506, SF 4 ·N(C 2 H 5 ) 3 2.499), as the nitrogen serves as an attractor.C orrespondingly,t here is an increase in negative charge in the ni- trogen atomicb asin upon adduct formation.T he atomic basin charge on F 1 becomes more negative upon adduct formation (SF 4 À0.670,S F 4 ·NC 5 H 5 À0.681, SF 4 ·4-NC 5 H 4 (CH 3 ) À0.681, SF 4 ·2,6-NC 5 H 3 (CH 3 ) 2 À0.681, SF 4 ·4-NC 5 H 4 N(CH 3 ) 2 À0.683, SF 4 ·N(C 2 H 5 ) 3 À0.685), whereas those of F 2 ,F 3 ,a nd F 4 are unaltered.…”

Section: Atoms In Molecules Analysissupporting

confidence: 91%

Lewis Acid Behavior of SF₄: Synthesis, Characterization, and Computational Study of Adducts of SF₄with Pyridine and Pyridine Derivatives

Chaudhary¹,

Goettel

Mercier

et al. 2015

Chemistry A European J

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Sulfur tetrafluoride was shown to act as a Lewis acid towards organic nitrogen bases, such as pyridine, 2,6-dimethylpyridine, 4-methylpyridine, and 4-dimethylaminopyridine. The SF4 ⋅NC5 H5 , SF4 ⋅2,6-NC5 H3 (CH3 )2 , SF4 ⋅4-NC5 H4 (CH3 ), and SF4 ⋅4-NC5 H4 N(CH3 )2 adducts can be isolated as solids that are stable below -45 °C. The Lewis acid-base adducts were characterized by low-temperature Raman spectroscopy and the vibrational bands were fully assigned with the aid of density functional theory (DFT) calculations. The electronic structures obtained from the DFT calculations were analyzed by the quantum theory of atoms in molecules (QTAIM). The crystal structures of SF4 ⋅NC5 H5 , SF4 ⋅4-NC5 H4 (CH3 ), and SF4 ⋅4-NC5 H4 N(CH3 )2 revealed weak SN dative bonds with nitrogen coordinating in the equatorial position of SF4 . Based on the QTAIM analysis, the non-bonded valence shell charge concentration on sulfur, which represents the lone pair, is only slightly distorted by the weak dative SN bond. No evidence for adducts between quinoline or isoquinoline with SF4 was found by low-temperature Raman spectroscopy.

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Section: Atoms In Molecules Analysissupporting

confidence: 91%

Lewis Acid Behavior of SF₄: Synthesis, Characterization, and Computational Study of Adducts of SF₄with Pyridine and Pyridine Derivatives

Chaudhary¹,

Goettel

Mercier

et al. 2015

Chemistry A European J

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“…Although the arguments presented here are developed for d 10 -ML 2 complexes, similar arguments account for the nonlinear structures observed for d 0 metal complexes with π-donating ligands [79][80][81][82][83]. Furthermore, similar reasoning is expected to account for a related effect described for d 8 -M(CO) 2 L 2 complexes by Eisenstein and Caulton, where strong π-accepting ligands induce non-planarity [84,85].…”

Section: The Effect Of Metal Variationsupporting

confidence: 62%

d10-ML2 Complexes: Structure, Bonding, and Catalytic Activity

Wolters¹,

Bickelhaupt

2014

Structure and Bonding

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Our goal in this chapter is to show how one can obtain a better understanding of the decisive factors for the selectivity and efficiency of catalytically active metal complexes. This ongoing research project has been designated the 'Fragment-oriented Design of Catalysts' and aims at providing design principles for a more rational development of catalysts. To this end, we have performed a series of studies in which we systematically investigate the effect of a specific variation on the reactivity of the catalyst. Thus, we will summarize previous results on not only how the reaction barrier varies when different bonds are activated by palladium, different ligands are attached to palladium but also how different metal centers perform compared to palladium. In a final section, we present a case study on newly obtained results about the effect of adding substituents with different electronegativity to the phosphine ligands at the metal center. A red thread throughout the chapter, and our methodology in general, is the application of the activation strain model of chemical reactivity. This is a predictive model that provides a quantitative relationship between trends in barrier heights and variation of geometric and electronic properties of the reactants.

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“…For example, whereas CO 2 and NO 2 + are linear and in accord with the model, CaF 2 , BaH 2, TiO 2 , VO 2 + , and CrO 2 + are bent in clear violation of the VESPR model. 45,46 Since L(r) is a physical property of a system and model independent, its topology should differ between that for main group molecules and those containing a metal atom to account for their differing geometries, and this is indeed the case. In the latter cases it is found that the outer core of the metal (with the shells of the core density defined by L(r)) is polarized to create CCs that unlike their adjacency to the ligands in main group molecules, are diagonally opposed to the positions of the ligands, giving rise to ligand-opposed CCs.…”

Section: Iv1 Example Of the Density Explaining And Correcting The Fmentioning

confidence: 99%

Definition of Molecular Structure: By Choice or by Appeal to Observation?

2010

Self Cite

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There are two schools of thought in chemistry: one derived from the valence bond and molecular orbital models of bonding, the other appealing directly to the measurable electron density and the quantum mechanical theorems that determine its behavior, an approach embodied in the quantum theory of atoms in molecules, QTAIM. No one questions the validity of the former approach, and indeed molecular orbital models and QTAIM play complementary roles, the models finding expression in the principles of physics. However, some orbital proponents step beyond the models to impose their personal stamp on their use in interpretive chemistry, by denying the possible existence of a physical basis for the concepts of chemistry. This places them at odds with QTAIM, whose very existence stems from the discovery in the observable topology of the electron density, the definitions of atoms, of the bonding between atoms and hence of molecular structure. Relating these concepts to the electron density provides the necessary link for their ultimate quantum definition. This paper explores in depth the possible causes of the difficulties some have in accepting the quantum basis of structure beginning with the arguments associated with the acceptance of a "bond path" as a criterion for bonding. This identification is based on the finding that all classical structures may be mapped onto molecular graphs consisting of bond paths linking neighboring atoms, a mapping that has no known exceptions and one that is further bolstered by the finding that there are no examples of "missing bond paths". Difficulties arise when the quantum concept is applied to systems that are not amenable to the classical models of bonding. Thus one is faced with the recurring dilemma of science, of having to escape the constraints of a model that requires a change in the existing paradigm, a process that has been in operation since the discovery of new and novel structures necessitated the extension of the Lewis model and the octet rule. The paper reviews all facets of bonding beginning with the work of Pauling and Slater in their accounting for crystal structures, taking note of Pauling's advocating possible bonding between large anions. Many examples of nonbonded or van der Waals interactions are considered from both points of view. The final section deals with the consequences of the realization that bonded quantum atoms that share an interatomic surface do not "overlap". The time has come for entering students of chemistry to be taught that the electron density can be seen, touched, and measured and that the chemical structures they learn are in fact the tracings of "bonds" onto lines of maximum density that link bonded nuclei. Matter, as we perceive it, is bound by the electrostatic force of attraction between the nuclei and the electron density.

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Trigonal Bipyramidal and Related Molecules of the Main Group Elements: Investigation of Apparent Exceptions to the VSEPR Model through the Analysis of the Laplacian of the Electron Density

Cited by 44 publications

References 0 publications

Lewis Acid Behavior of SF₄: Synthesis, Characterization, and Computational Study of Adducts of SF₄with Pyridine and Pyridine Derivatives

Lewis Acid Behavior of SF₄: Synthesis, Characterization, and Computational Study of Adducts of SF₄with Pyridine and Pyridine Derivatives

d10-ML2 Complexes: Structure, Bonding, and Catalytic Activity

Definition of Molecular Structure: By Choice or by Appeal to Observation?

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Trigonal Bipyramidal and Related Molecules of the Main Group Elements: Investigation of Apparent Exceptions to the VSEPR Model through the Analysis of the Laplacian of the Electron Density

Cited by 44 publications

References 0 publications

Lewis Acid Behavior of SF4: Synthesis, Characterization, and Computational Study of Adducts of SF4with Pyridine and Pyridine Derivatives

Lewis Acid Behavior of SF4: Synthesis, Characterization, and Computational Study of Adducts of SF4with Pyridine and Pyridine Derivatives

d10-ML2 Complexes: Structure, Bonding, and Catalytic Activity

Definition of Molecular Structure: By Choice or by Appeal to Observation?

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Product

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Lewis Acid Behavior of SF₄: Synthesis, Characterization, and Computational Study of Adducts of SF₄with Pyridine and Pyridine Derivatives

Lewis Acid Behavior of SF₄: Synthesis, Characterization, and Computational Study of Adducts of SF₄with Pyridine and Pyridine Derivatives