Theoretical analysis of hydrocarbon properties. 2. Additivity of group properties and the origin of strain energy

Wiberg, Kenneth B.; Bader, R. F. W.; Lau, C. D. H.

doi:10.1021/ja00238a005

Cited by 253 publications

(222 citation statements)

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“…Vol. 74, 1996 However, as pointed out by Wiberg et al (23), in reality the charge density between bridgehead carbons is around 80% of that corresponding to the C2-C3 bond in n-butane; this density accumulation, due mainly to a superposition of atomic densities, can also produce a partial bond between the bridgehead atoms (central bond). Indeed, the Bader analysis (24; see also ref.…”

Section: Propellanesmentioning

confidence: 98%

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Quantum chemical valence indices from the one-determinantal difference approach

Nalewajski¹,

Mrozek²,

Mazur³

1996

Can. J. Chem.

135

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The recently introduced quadratic (two-electron) valence indices, ionic and covalent, derived from the HartreeFock finite-difference approach, are applied to selected organic and inorganic molecules to demonstrate their utility in monitoring chemical bonding patterns in molecular systems. The indices are defined in terms of differerences between simultaneous probabilities of finding two electrons on specified atoms, calculated from the molecular and separated-atomlimit (SAL) wave functions, respectively, in the UHF approximation. The total quadratic valence number represents the overall number of chemical bonds in the system under consideration; it is interpreted as the molecular expectation value of the difference operator of the molecular and SAL density operators. This interpretation leads to a new set of ionic atomic and diatomic valence components; these modified valence numbers are discussed using the two-orbital model in the UHF scheme. A new procedure is proposed for dividing the one-center contributions to the bond valences; it generates effective bond orders in qood agreement with chemical expectations. The new valence quantities are tested on selected typical molecules and prototype hydrogen-bonded dimers. A more extensive study has been canied out on small-ring propellanes, to examine changes in bond valences between bridgehead atoms in selected systems.

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Section: Propellanesmentioning

confidence: 98%

“…Indeed, the Bader analysis (24; see also ref. 25) of the Laplacian of the molecular density indicates a presence of the bond critical point in the [ 1.1. llpropellane central region (23).…”

Section: Propellanesmentioning

confidence: 99%

Quantum chemical valence indices from the one-determinantal difference approach

Nalewajski¹,

Mrozek²,

Mazur³

1996

Can. J. Chem.

135

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“…The second derivative of the electron density (Laplacian) ∇ 2 ρ(r) reveals information about the concentration or depletion of the elections at the BCP. It has been shown that the ∇ρ(r) and ∇ 2 ρ(r) at the BCP are directly related to the bond order and thus to the bond strength [33], for which the bond dissociation energy (E BD ) can be estimated using the potential energy density V (r BCP ), i.e., E BD =− 1 2 V (r BCP ). Here we used the virial theorem which relates the V (r BCP ) and the kinetic energy density G (r BCP )tothe∇ 2 ρ(r BCP ), such as, Tables I -III. …”

Section: Appendix B: Topological Analysis Of the Electron Densitymentioning

confidence: 99%

Stable structures of He andH2Oat high pressure

2015

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/npsi/ctrl?action=rtdoc&an=21276923&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21276923&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

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“…This approach works well for covalently-linked atoms [92][93][94] and was recently used by one of us to rationalize the difference is stability of Zn 2+ complexes with nitrilotriacetic acid and nitrilotri-3-propanoic acid.…”

Section: 92mentioning

confidence: 97%

“…91 You et al 95 expounded on this approach to evaluate the strain of a particular bent bond instead of the strain of the molecule as a whole.…”

Section: 92mentioning

confidence: 99%

A Density Functional Theory and Quantum Theory of Atoms-in-Molecules Analysis of the Stability of Ni(II) Complexes of Some Amino Alcohol Ligands

et al. 2011

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The structure of the complexes of the type [Ni(L)(, where L is an amino-alcohol ligand, L = N,N , N,N'-bis(2-hydroxycyclohexyl)-ethane-1,2-diamine (Cy 2 EN) and N,N'-bis(2-hydroxycyclopentyl)-ethane-1,2-diamine, (Cyp 2 EN) were investigated at the X3LYP/6-31+G(d,p) level of theory both in the gas phase and in solvent (CPCM model) to gain insight into factors that control the experimental log K 1 values. We find that (i) analyses based on Bader's quantum theory of atoms in molecules (QTAIM) are useful in providing significant insight into the nature of metal-ligand bonding and in clarifying the nature of weak "non-bonded" interactions in these complexes, and (ii) the conventional explanation of complex stability in these sorts of complexes (based on considerations of bond lengths, bite angles and H-clashes) could be inadequate and indeed might be misleading. The strength of metal-ligand bonds follows the order Ni-N > Ni-OH  Ni-OH 2 ; the bonds are predominantly ionic with some covalent character decreasing in the order Ni-N > Ni-OH > Ni-OH 2 , with Ni-OH 2 being close to purely ionic. We predict that the cis complexes are preferred over the trans complexes because of (i) stronger bonding to the alcoholic O-donor atoms and (ii) more favorable intramolecular interactions, which appear to be important in determining the conformation of a metal-ligand complex. We show that (i) the flexibility of the ligand, which controls the Ni-OH bond length, and (ii) the ability of the ligand to donate electron density to the metal are likely to be important factors in determining values of log K 1 . We find that the electron density at the ring critical point of the cyclopentyl moieties in Cyp 2 EN is much higher than that in the cyclohexyl moieties of Cy 2 EN and interpret this to mean that Cyp 2 EN is a poorer donor of electron density to a Lewis acid than Cy 2 EN.2

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Theoretical analysis of hydrocarbon properties. 2. Additivity of group properties and the origin of strain energy

Cited by 253 publications

References 1 publication

Quantum chemical valence indices from the one-determinantal difference approach

Quantum chemical valence indices from the one-determinantal difference approach

Stable structures of He andH2Oat high pressure

A Density Functional Theory and Quantum Theory of Atoms-in-Molecules Analysis of the Stability of Ni(II) Complexes of Some Amino Alcohol Ligands

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