trans-1,2-Dicyano-cyclopropane and other cyano-cyclopropane derivatives

Jalkanen, K. J.; Gale, Julian D.; Jalkanen, G. J.; McIntosh, Douglas F.; El-Azhary, Adel A.; Jensen, Greg

doi:10.1007/s00214-007-0391-6

Cited by 8 publications

(4 citation statements)

References 111 publications

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“…This study, and the earlier study of -acceptor substitution of cyclopropane (Cruz-Cabeza & Allen, 2011), has shown an excellent level of agreement between the DFT results and those obtained by careful analysis of available crystal structures in the CSD. As far as the DFT analysis is concerned, this supports the view of Jalkanen et al (2008) that the B3PW91/ aug-cc-pVTZ is an appropriate level of theory for calculations involving cyclopropane. However, despite the large number of structures of substituted cyclopropanes now available in the CSD, it remains difficult to locate structures in which asymmetry in the ring bond lengths is solely due to a single substituent type, hence restricting the chemical diversity of substituents available for the type of comparative analysis attempted here.…”

Section: Resultssupporting

confidence: 68%

“…Molecular models were then geometry optimized using GAUSSIAN03 (Frisch et al, 2004) at the B3PW91/aug-cc-pVTZ level of theory. The level of theory was chosen because of a recent highly detailed theoretical and experimental study (Jalkanen et al, 2008) concluding that the B3PW91 hybrid functional with the aug-cc-pVTZ basis set reproduced geometrical and vibrational data with high precision for cyano-cyclopropane derivatives.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

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Geometry and conformation of cyclopropane derivatives having σ-acceptor and σ-donor substituents: a theoretical and crystal structure database study

Cruz‐Cabeza

Allen

2012

Acta Crystallogr Sect B

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The structures of cyclopropane rings which carry σ-acceptor or σ-donor substituents have been studied using density-functional theory (DFT), and mean bond lengths and conformational parameters retrieved from the Cambridge Structural Database. It is confirmed that σ-acceptor substituents, e.g. halogens, generate positive ring bond-length asymmetry in which there is lengthening of the distal bond (opposite to the point of substitution), and shortening of the two vicinal bonds. This is due to withdrawal of electron density from the cyclopropane 1e′′ orbitals, which are bonding for the distal bond and antibonding for the vicinal bonds. For σ-donor substituents such as SiH3 or Si(CH3)3, the DFT and crystal structure data show negative ring bond-length asymmetry (distal bond shortened, vicinal bonds lengthened), owing to electron donation into the 4e′ ring orbital, which are also bonding for the distal bond and antibonding for the vicinal bonds. The results also show that —OH substituents induce weak positive asymmetry, but that the effects of methyl or amino substituents are either non-existent or extremely small, certainly too small to measure using crystal structure information.

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Section: Resultssupporting

confidence: 68%

Section: Ab Initio Calculationsmentioning

confidence: 99%

Geometry and conformation of cyclopropane derivatives having σ-acceptor and σ-donor substituents: a theoretical and crystal structure database study

Cruz‐Cabeza

Allen

2012

Acta Crystallogr Sect B

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“…(i) B3LYP/6-311+G** and (ii) B3PW91/aug-cc-pVTZ. The B3LYP method was chosen because of its popularity and for comparison purposes, whilst the B3PW91 method was chosen because of the recent work by Jalkanen et al (2008). This highly detailed theoretical and experimental study concluded that the B3PW91 hybrid functional with the aug-cc-pVTZ basis set reproduced geometrical and vibrational data with high precision for cyano-cyclopropane derivatives.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

Conformation and geometry of cyclopropane rings having π-acceptor substituents: a theoretical and database study

Cruz‐Cabeza

Allen

2010

Acta Crystallogr Sect B

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The 3e' orbitals of cyclopropane have the correct symmetry to interact with low-lying unoccupied orbitals of π-acceptor substituents and maximum overlap occurs when the two orbital systems are parallel, i.e. when the π-acceptor bisects the ring in projection down the substituent bond. Since the cyclopropyl group is a common component of active pharmaceutical and agrochemical ingredients, it is important that these strong conjugative interactions are well modelled by computational techniques, and clearly represented in experimental crystal structures. Here we show that torsion angle distributions derived from crystal structure data in the Cambridge Structural Database are in excellent correspondence with torsional energy profiles computed using density functional theory (DFT) for a range of substituents: -COOR, -CONR(2), -NO(2), vinyl and phenyl. We also show that crystal structure information is invaluable in modelling conformations of compounds that contain multiply substituted rings, where steric interactions require some substituents to adopt energetically disfavoured conformations. Further, conjugative interactions with π-acceptors lead to significant asymmetry in the cyclopropane ring bond lengths and again the experimental and computational results are in excellent agreement. Such asymmetry effects are additive, and this explains bond-length variations in cyclopropane rings bearing two or more π-acceptor substituents.

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“…[28][29][30][31][32][33][34][35][36][37][38] Most of these studies are concerned with local chirality, generally associated with asymmetric C atoms, while there exists another type of chirality, axial chirality, which is associated with the helical shape. This delocalized chirality is also associated with specific signatures, as discussed recently for model chains of synthetic [39][40][41] and natural 42,43 polymers.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Raman optical activity of π‐conjugated helical systems: Hexahelicene and heterohelicenes

Liégeois¹,

Champagne²

2008

J Comput Chem

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Helicenes constitute a special class of molecules combining helical conformation with pi-electron delocalization. These confer to helicenes specific chirooptical properties. In this article, we investigate the vibrational signatures thanks to the simulation of vibrational Raman optical activity (VROA) spectra. For that, four representative helicenes: hexahelicene, tetrathia-[7]-helicene, and its pyrrole and furan analogs have been simulated and interpreted using a recently implemented analytical scheme. Helicenes show intense VROA peaks attributed to their pi-conjugated structure and associated with collective vibrational modes. In hexahelicene, the dominant VROA features are due to vibrational modes involving motions of the carbon skeleton and H-wagging, but the intensity finds its source almost exclusively in the former. In the case of the three heterohelicenes, the previous statement is also verified, and on changing the heteroatoms, similar modes presenting comparable atomic contribution patterns have been highlighted, though the vibrational and electronic properties are modified. Some fingerprints could therefore be associated with the helicity of the system. In particular, in forward spectra, most of the VROA bands are positive for left-handed helicenes. Nevertheless, the spectral patterns are quite complex, and no easy rule-of-thumb could distinguish between the different heterohelicenes. Then, considering the fact that most of the contributions originate from the C atoms (group coupling matrices decomposition), it can be concluded that the major role of the heteroatom is restricted to modifying the geometry and the normal modes. At last, the small impact of the gauge-origin on the calculated spectra using a relatively modest basis set (rDPS:3-21G) is demonstrated here in the case of the tetrathia-[7]-helicene molecule presenting a C(2) symmetry. This further demonstrates the adequacy of this basis set for VROA calculations.

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trans-1,2-Dicyano-cyclopropane and other cyano-cyclopropane derivatives

Cited by 8 publications

References 111 publications

Geometry and conformation of cyclopropane derivatives having σ-acceptor and σ-donor substituents: a theoretical and crystal structure database study

Geometry and conformation of cyclopropane derivatives having σ-acceptor and σ-donor substituents: a theoretical and crystal structure database study

Conformation and geometry of cyclopropane rings having π-acceptor substituents: a theoretical and database study

Vibrational Raman optical activity of π‐conjugated helical systems: Hexahelicene and heterohelicenes

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