Natural resonance theory: II. Natural bond order and valency

Glendening, Eric D.; Weinhold, Frank

doi:10.1002/(sici)1096-987x(19980430)19:6<610::aid-jcc4>3.0.co;2-u

Cited by 470 publications

(103 citation statements)

References 54 publications

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“…A similar approach was adopted by Jug et al [267,292,293]. A different line of reasoning is the natural-resonance method, aka natural bond orbitals (NBO) [294,295] that are obtained from averaged weighted resonance forms. This method yields "chemist" bond orders composed of ionic and covalent contributions, and the results are similar [291,295] to those obtained with the Mayer method.…”

Section: C-2 Calculations Of Bond Ordermentioning

confidence: 99%

“…A different line of reasoning is the natural-resonance method, aka natural bond orbitals (NBO) [294,295] that are obtained from averaged weighted resonance forms. This method yields "chemist" bond orders composed of ionic and covalent contributions, and the results are similar [291,295] to those obtained with the Mayer method. The NBO methods are used across the periodic table [296,297] and have been developed further [298,299].…”

Section: C-2 Calculations Of Bond Ordermentioning

confidence: 99%

“…Besides bond orders, Mayer [264] and others [267,295] calculate a value termed valence or valence number, which in a homoleptic molecule is the absolute value of OS for an atom. An explicit quantum-chemical calculation of OS is suggested by Zhan et al [301] and shown to work for sp molecules below a certain level of complexity.…”

Section: C-3 Direct Quantum-chemical Calculation Of Osmentioning

confidence: 99%

See 2 more Smart Citations

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Karen

McArdle

Takats

2014

Pure and Applied Chemistry

111

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A generic definition of oxidation state (OS) is formulated: "The OS of a bonded atom equals its charge after ionic approximation". In the ionic approximation, the atom that contributes more to the bonding molecular orbital (MO) becomes negative. This sign can also be estimated by comparing Allen electronegativities of the two bonded atoms, but this simplification carries an exception when the more electronegative atom is bonded as a Lewis acid. Two principal algorithms are outlined for OS determination of an atom in a compound; one based on composition, the other on topology. Both provide the same generic OS because both the ionic approximation and structural formula obey rules of stable electron configurations. A sufficiently simple empirical formula yields OS via the algorithm of direct ionic approximation (DIA) by these rules. The topological algorithm works on a Lewis formula (for a molecule) or a bond graph (for an extended solid) and has two variants. One assigns bonding electrons to more electronegative bond partners, the other sums an atom's formal charge with bond orders (or bond valences) of sign defined by the ionic approximation of each particular bond at the atom. A glossary of terms and auxiliary rules needed for determination of OS are provided, illustrated with examples, and the origins of ambiguous OS values are pointed out. An electrochemical OS is suggested with a nominal value equal to the average OS for atoms of the same element in a moiety that is charged or otherwise electrochemically relevant.

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Section: C-2 Calculations Of Bond Ordermentioning

confidence: 99%

Section: C-2 Calculations Of Bond Ordermentioning

confidence: 99%

Section: C-3 Direct Quantum-chemical Calculation Of Osmentioning

confidence: 99%

See 1 more Smart Citation

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Karen

McArdle

Takats

2014

Pure and Applied Chemistry

111

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“…For the zinc clusters, the Stevens-Basch-Krauss-Jasien pseudopotential 19 (and associated basis set) was used. Natural resonance theory analysis 25,26,27 was performed with NBO 5.G.…”

Section: Methodsmentioning

confidence: 99%

Unravelling the Reaction Mechanism of the Reductive Ring Contraction of 1,2-Pyridazines

Silva

2012

J. Org. Chem.

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“…So, alternative Natural Resonance Theory Analysis (NRT) [73,74,75] had to be employed. It demosntrated that the negative charge in the Lewis structure of the ylide is mainly placed on C5.…”

Section: Scheme 19mentioning

confidence: 99%

Coinage metal complexes as chiral catalysts for 1,3-dipolar cycloadditions

Nájera

Sansano

2014

Journal of Organometallic Chemistry

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In this account, we describe the experience of our research group in the implementation of chiral coinage metal complexes into the efficient enantioselective 1,3-DC of azomethine ylides derived from α-amino acids and azlactones with different dipolarophiles. The corresponding chiral metallodipoles were generated in situ and next focused on the synthesis of highly substituted prolines. For this purpose, privileged ligands such as phosphoramidites and binap with silver(I), gold(I) and copper(II) salts are described. Depending from the ligand and mainly from the metal salt it can be possible to control the facial endo/exo-diasteroselectivity and the enantioselectivity of these types of processes. The synthetic processes are also supported by DFT calculations in order to elucidate the most plausible mechanism and the stereochemical results.

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Natural resonance theory: II. Natural bond order and valency

Cited by 470 publications

References 54 publications

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Unravelling the Reaction Mechanism of the Reductive Ring Contraction of 1,2-Pyridazines

Coinage metal complexes as chiral catalysts for 1,3-dipolar cycloadditions

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