The electronic structure of nitrilimines revisitedElectronic supplementary information (ESI) available: Optimized structures and absolute energies of all stationary points. See http://www.rsc.org/suppdata/cc/b4/b407302a/

Mawhinney, Robert C.; Muchall, Heidi M.; Peslherbe, Gilles H.

doi:10.1039/b407302a

Cited by 29 publications

(34 citation statements)

References 17 publications

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“…[69] Weinholds natural resonance theory (NRT) has also been applied by Mawhinney et al towards understanding the electronic structure of nitrilimines. [70] They concluded that nitrilimines had significant carbene character. However, Ponti and co-workers have used CASSCF and spin-coupled calculations to show that the most important electronic structure of nitrilimines corresponds to the propargylic resonance form with little or no carbenic character.…”

Section: Configuration Mixing Modelsmentioning

confidence: 99%

Conceptual, Qualitative, and Quantitative Theories of 1,3‐Dipolar and Diels–Alder Cycloadditions Used in Synthesis

2006

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Abstract:The application and performance of conceptual and qualitative theories and quantitative quantum mechanical methods to the study of mechanism, reactivity, and selectivity of 1,3-dipolar and Diels-Alder cycloadditions are reviewed. This review emphasizes the application of conceptual density functional theory (DFT) for predicting reactivity and regioselectivity, and highly accurate quantum mechanical methods for predicting barrier heights and reaction energetics. Applications of computations to solvation effects, metal and organocatalysis, are also described.

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Section: Configuration Mixing Modelsmentioning

confidence: 99%

Conceptual, Qualitative, and Quantitative Theories of 1,3‐Dipolar and Diels–Alder Cycloadditions Used in Synthesis

2006

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“…These equations can readily be expanded to include additional orbital interactions. Since the ethene orbitals are the same throughout and the shapes of the nitrilimine orbitals are qualitatively similar (32), one may assume that the atomic orbital coefficients are relatively constant, and their products may be approximated by a general factor (K). Additionally, the distance between the interacting centres is moderately invariant (Table 1), and so β may also be considered constant.…”

Section: Frontier Molecular Orbitalsmentioning

confidence: 99%

A computational study of the 1,3-dipolar cycloaddition reaction mechanism for nitrilimines

Mawhinney¹,

Muchall²,

Peslherbe³

2005

Can. J. Chem.

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The [3+2] and [1+2] cycloaddition pathways between ethene and a series of 13 nitrilimines (R1CNNR2) have been examined by density functional theory [PBE0/6-311++G(2df,pd)] calculations. All reactions have low barriers ranging from 14.14 (R1 = CH3, R2 = H) to 1.01 (R1 = R2 = F) kcal mol1, and large reaction exothermicities consistent with the transient nature of nitrilimines. The [3+2] and [1+2] transition-state structures are very similar, mainly differing in the relative orientation of their fragments and the newly forming CC bond distance, and exhibit only minor deviations from the structures of the reactants. Both reaction pathways are concerted and asynchronous, but the [1+2] reaction has a greater degree of asynchronicity. Examination of the frontier molecular orbitals reveals that both the [3+2] and [1+2] barrier heights are related to two sets of orbital interactions, with the interaction between the lowest unoccupied molecular orbital π [Formula: see text] of nitrilimine and the highest occupied molecular orbital of ethene in common. The second interaction in both cases is carbene-like. A relationship between the weights of the 1,3-dipolar resonance contribution in the various nitrilimines and the corresponding [3+2] barrier heights was not found, but a good correlation could be found between the [1+2] barrier heights and both the 1,3-dipolar and carbene contributions. Inspection of the potential energy surface in the vicinity of the two transition states for the reaction between unsubstituted nitrilimine and ethene suggests that the observed [3+2] product is a result of an initial carbene-like approach of the two fragments followed by a ridge bifurcation that leads to the [3+2] product minimum. Key words: nitrilimines, 1,3-dipole, carbene, [3+2] cycloaddition, [1+2] cycloaddition, density functional theory (DFT).

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“…[20] Different ways to describe the geometric and electronic structures of the parent nitrile imine have also been reported by means of valence bond (VB) calculations. [20] Different ways to describe the geometric and electronic structures of the parent nitrile imine have also been reported by means of valence bond (VB) calculations.…”

Section: Introductionmentioning

confidence: 99%

“…This is particularly noticeable by the CNN antisymmetric stretching IR absorption of the nitrile imine moiety appearing over a wide range of frequencies (2000-2250 cm -1 ). [20,29,30] For instance, Bégué and Wentrup have theo-retically investigated different amino-, hydroxy-, and fluorosubstituted nitrile imines (R-CNN-H, H-CNN-R, and R-CNN-R; R = NH 2 , OH, and F) and predicted that some of the studied molecules should exhibit carbenic character. [17] In addition, theoretical studies have indicated that substituents bearing a lone-electron pair should increase the importance of the carbenic resonance structure of nitrile imines.…”

Section: Introductionmentioning

confidence: 99%

The Quest for Carbenic Nitrile Imines: Experimental and Computational Characterization of C‐Amino Nitrile Imine

et al. 2015

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C‐Amino nitrile imine has been generated as primary photoproduct (λ = 220 nm) of 5‐amino‐2H‐tetrazole isolated in an argon matrix at 15 K. Subsequent photochemical experiments (λ = 330 nm) demonstrated that C‐amino nitrile imine isomerizes to the corresponding three‐membered‐ring 1H‐diazirine and decomposes to methylenimine. The experimentally observed νas(CNN) absorption at 1998 cm–1 and a carbenic resonance structure contribution of around 20 %, predicted by natural resonance theory calculations, demonstrate that the protoproduced C‐amino nitrile imine has significant carbenic character. These results pave the way to the discovery of carbenic nitrile imines.

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The electronic structure of nitrilimines revisitedElectronic supplementary information (ESI) available: Optimized structures and absolute energies of all stationary points. See http://www.rsc.org/suppdata/cc/b4/b407302a/

Cited by 29 publications

References 17 publications

Conceptual, Qualitative, and Quantitative Theories of 1,3‐Dipolar and Diels–Alder Cycloadditions Used in Synthesis

Conceptual, Qualitative, and Quantitative Theories of 1,3‐Dipolar and Diels–Alder Cycloadditions Used in Synthesis

A computational study of the 1,3-dipolar cycloaddition reaction mechanism for nitrilimines

The Quest for Carbenic Nitrile Imines: Experimental and Computational Characterization of C‐Amino Nitrile Imine

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