The molecular structure of 1,1-dicyanocyclopentane from gas electron diffraction data and ab initio calculations

Dakkouri, Marwan; Typke, V.

doi:10.1016/s0022-2860(02)00089-3

Cited by 8 publications

(30 citation statements)

References 21 publications

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“…Naturally, this leads to a shortening of this bond. It is noteworthy that this kind of interpretation of the topological properties of the C-C"N fragment to a wide extent parallels the rationalization which has been proposed earlier by Politzer et al [21-22, 28, 29] and was confirmed by some of our investigations on triply bonded carbon atom [1,30,31]. This concept is based on electron charge density distribution analysis, which shows that a significant fraction of the p-electrons of the carbon triple bond is spread over the neighboring regions (denoted ''outer'' p charge).…”

Section: S Symmetric Form Of Dccp and Dclcpsupporting

confidence: 90%

“…All these variations of the endocyclic C-C bonds in both the C s and C 2 conformers of DCCP and DClCP have been previously reasonably rationalized [1][2][3]. In these papers we presented a mathematical model elucidating this dependency of the geometrical parameters on the phase angle u and thus on the instantaneous symmetry of geminally substituted five-membered ring systems (e.g.…”

Section: Inspection Of the Values Inmentioning

confidence: 87%

“…The nitrogen lone pairs donate electrons into the anti-bonding orbitals of the vicinal and distal carbon atoms leading to a slight shortening of the C"N bond and bending of the C-C"N chain. However, the appreciable repulsive interaction between the lone-pairs on the nitrogens oppose the proximity of the distal N -...C + charged atoms and the result is an outwards bending of the C-C"N moieties by 2.3°as predicted by the DFT method, and 5.3°(r a value) as obtained from the electron diffraction experiment [1].…”

Section: S Symmetric Form Of Dccp and Dclcpmentioning

confidence: 89%

“…Recently we published a paper on the molecular structure of 1,1-dicyanocyclopentane (DCCP) [1]. In this work, we studied the dependency of various structural parameters on the pseudorotational motion in this molecule.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical analysis of bonding properties in 1,1-dicyanocyclopentane and 1,1-dichlorocyclopentane by applying the AIM and NBO approaches

Dakkouri

Typke

2007

Struct Chem

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Using Bader's quantum-topological theory of atoms in molecules (AIM) and Weinhold's Natural Bond Orbital (NBO) analysis we could rationalize the impact of the geminal substitution by C"N and Cl on the geometry and electronic structure of the cyclopentane ring in 1,1-dicyanocyclopentane (DCCP) and 1,1-dichlorocyclopentane (DClCP). Among the crucial results we obtained are: 1. The topological quantities, particularly the bond ellipticity of 0.035 for the C-CN bond, indicate that this bond possesses higher bond order than a single bond. This conclusion is clearly supported by the NBO results. 2. The AIM theory as well as the NBO analysis confirm uniformly the non-linearity of the C-C"N moiety. 3. Regardless the quantum mechanical method that has been employed for a variety of nitriles the sign of the Laplacian of the charge density, Ñ 2 q(r), of the C"N group changes its sign from negative to positive upon moving from the triple zeta to the double zeta basis set. A possible explanation for this striking behavior has been provided. By invoking the AIM and NBO approaches the different endocyclic C-C bond lengths in DCCP and DClCP as a consequence of the geminal substitution could be explained. Also the variations of these bond lengths upon moving from the more stable C s to the energetically less favorable C 2 conformer of both compounds could be rationalized. For the purpose of comparison and verification of some findings of this work, we also carried out AIM and NBO calculations on various related cyclic and non-cyclic compounds.

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Section: S Symmetric Form Of Dccp and Dclcpsupporting

confidence: 90%

Section: Inspection Of the Values Inmentioning

confidence: 87%

Section: S Symmetric Form Of Dccp and Dclcpmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical analysis of bonding properties in 1,1-dicyanocyclopentane and 1,1-dichlorocyclopentane by applying the AIM and NBO approaches

Dakkouri

Typke

2007

Struct Chem

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“…Recently we published a series of papers on the molecular structures and bonding properties of 1,1 disubstituted cyclopentanes [1][2][3][4]. One of the main results of these investigations was the successful combination of the experimental method of gasphase electron diffraction with ab initio calculations to determine a molecular structure which is consistent with the large amplitude motion present in five-membered rings, the pseudorotation.…”

Section: Introductionmentioning

confidence: 99%