Valence and Tautomerism.

Bray, William C.; Branch, Gerald E. K.

doi:10.1021/ja02199a003

Cited by 17 publications

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“…[43] Once again, at the equilibrium NÀCr bond distance,t he lowest VB structure is the "no-bond" one,t hat is,t he formally "ionic" structure,N:Cr, which has some weak nonbonding interactions.8 3kcal mol À1 above it there lies the covalent structure, ( + NCC Cr À )i nw hich the two single electrons are spin-paired. As in the above dative bond, here too,the only NÀCr bonding that may emerge is due to the mixing of these two VB structures,a nd is hence aC SB.T he corresponding RE CS shown underneath the VB-mixing diagram is 67 %o ft he corresponding bond energy (Table S2:BDE = 31.4 kcal mol À1 relative to separated H 3 N: + Cr(CO) 5 ).…”

Section: Charge-shift Bonding In Dative and Coordinative Bondsmentioning

confidence: 72%

“…[42] As imilar situation was found for the related molecule,H 3 N À BF 3 (Table S2). Figure 8b depicts the VB-mixing diagram for ab ond between ammonia (NH 3 )a nd chromium pentacarbonyl (Cr-(CO) 5 ). Thelatter fragment is isolobal to BH 3 .…”

Section: Charge-shift Bonding In Dative and Coordinative Bondsmentioning

confidence: 99%

“…Examples of L-Cr(CO) 5 complexes with the L-Cr bond being aC SB are abundant and easily predictable.F urthermore,t here exist numerous coordinative bonds between…”

Section: Charge-shift Bonding In Dative and Coordinative Bondsmentioning

confidence: 99%

“…Indeed, the ubiquity of ions among inorganic compounds led initially to the formulation of the "dualistic electric theory" of bonding by Berzelius and Davy. [2,3a] This theory postulated the existence of union due to attractions between oppositely charged ions.A tt he same time,o rganic chemists explored the ideas of "valence" and "structure" [5] and had no use for ionicity,and hence,they dismissed the ionic theory.As such, aunified theory of union was needed in order to bridge these very diametrically different concepts. [4b-d, 5, 6] This was the situation when the electron was discovered and characterized by J. J. Thomson as as ource of negative electricity.S ubsequently,the inner structure of the atom was revealed by Rutherford to involve ap ositively charged nucleus "surrounded" by electrons.T he concept of ionic bonding was soon revived by Thomson.…”

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confidence: 99%

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Charge‐Shift Bonding: A New and Unique Form of Bonding

et al. 2019

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Charge‐shift bonds (CSBs) constitute a new class of bonds different than covalent/polar‐covalent and ionic bonds. Bonding in CSBs does not arise from either the covalent or the ionic structures of the bond, but rather from the resonance interaction between the structures. This Essay describes the reasons why the CSB family was overlooked by valence‐bond pioneers and then demonstrates that the unique status of CSBs is not theory‐dependent. Thus, valence bond (VB), molecular orbital (MO), and energy decomposition analysis (EDA), as well as a variety of electron density theories all show the distinction of CSBs vis‐à‐vis covalent and ionic bonds. Furthermore, the covalent–ionic resonance energy can be quantified from experiment, and hence has the same essential status as resonance energies of organic molecules, e.g., benzene. The Essay ends by arguing that CSBs are a distinct family of bonding, with a potential to bring about a Renaissance in the mental map of the chemical bond, and to contribute to productive chemical diversity.

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Section: Charge-shift Bonding In Dative and Coordinative Bondsmentioning

confidence: 72%

Section: Charge-shift Bonding In Dative and Coordinative Bondsmentioning

confidence: 99%

“…Examples of L-Cr(CO) 5 complexes with the L-Cr bond being aC SB are abundant and easily predictable.F urthermore,t here exist numerous coordinative bonds between…”

Section: Charge-shift Bonding In Dative and Coordinative Bondsmentioning

confidence: 99%

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confidence: 99%

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Charge‐Shift Bonding: A New and Unique Form of Bonding

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“…While Gerald Branch was a graduate student in 1913 he published a paper with Bray entitled "Valence and Tautomerism" (1) in which he intro duced the idea, obviously as a result of discussions with Lewis (and remember, Branch had only been here one year as a graduate student). ,…”

Section: Lewis' Electron Pair Bond Concept Initiates Theoretical Orgamentioning

confidence: 99%

Gilbert Newton Lewis: His influence on physical-organic chemists at Berkeley

Calvin¹

1984

J. Chem. Educ.

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There will be a review of the historical contributions of Gilbert N.Lewis to science and a discussion of the influence of Lewis on the research of the members of the physical-organic staff at Berkeley, including Melvin Calvin, during the twenties, thirties and forties. Some specific examples will be discussed. Also, the effect of Lewis, his science and administra tive concepts in the creation of excellence in a department of chemistry will be reviewed.

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Charge‐Shift Bonding: A New and Unique Form of Bonding

et al. 2019

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Stichwçrter: bond theory ·charge-shift bonds · covalent bonds ·ionic bonds ·v alence bonds Dedicated to Roald HoffmannAbstract: Charge-shift bonds (CSBs) constitute anew class of bonds different than covalent/polar-covalent and ionic bonds. Bonding in CSBs does not arise from either the covalent or the ionic structures of the bond, but rather from the resonance interaction between the structures.T his Essay describes the reasons why the CSB family was overlooked by valence-bond pioneers and then demonstrates that the unique status of CSBs is not theory-dependent. Thus,v alence bond (VB), molecular orbital (MO), and energy decomposition analysis (EDA), as well as av ariety of electron density theories all show the distinction of CSBs vis-à-vis covalent and ionic bonds. Furthermore,t he covalent-ionic resonance energy can be quantified from experiment, and hence has the same essential status as resonance energies of organic molecules,e .g., benzene. The Essaye nds by arguing that CSBs are ad istinct family of bonding,w ith ap otential to bring about aR enaissance in the mental map of the chemical bond, and to contribute to productive chemical diversity.

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Valence and Tautomerism.

Cited by 17 publications

References 0 publications

Charge‐Shift Bonding: A New and Unique Form of Bonding

Charge‐Shift Bonding: A New and Unique Form of Bonding

Gilbert Newton Lewis: His influence on physical-organic chemists at Berkeley

Charge‐Shift Bonding: A New and Unique Form of Bonding

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