C22H46: The smallest open 31-knotted alkane by computer-aided design

Krinas, Christos S.; Demetropoulos, Ioannis N.

doi:10.1016/j.jmgm.2007.10.010

Cited by 5 publications

(11 citation statements)

References 40 publications

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“…By removing segment lengths that are less likely to produce tight knots, the TKCS can be further reduced to 5.5 £ 10 8 . In [27], the TCS size of C 30 H 62 is stated to be 9.9 £ 10 14 , while TKCS is reported to be seven orders of magnitude smaller (16,656,192).…”

Section: The Gmk Algorithmmentioning

confidence: 99%

“…(1) Conformer generation step: Molecular conformations with inherent knot topology are created by applying the theory of open polygonal knots at dihedral space, (2) Math filter step: Each structure is evaluated for knottiness by calculating the Alexander polynomial D(t) [17,26,27],…”

Section: The Gmk Algorithmmentioning

confidence: 99%

“…This chart does not include the quantum step since that only serves as a shape optimiser [17,27] knottiness is generally preserved. Moreover, the first three steps of the algorithm are the most computationally expensive.…”

Section: The Gmk Algorithmmentioning

confidence: 99%

“…the molecule is described as a multi-spring device). The algorithm has been shown to be quite efficient for short chain lengths, where all other methods fail [27]. The build-up of a 4 1 knot at molecular level is illustrated in Figure 3, while the sequence of twists that lead to a figure-eight knot, realised in a rope, is presented in Figure 4.…”

Section: The Gmk Algorithmmentioning

confidence: 99%

“…Hence, the related topological indicator is knottiness , f (macromolecules length, number of linear segments) [17]. Furthermore, it has been shown [27] that knottiness induces bond elongation and valence angle distortion so a possible QSAR is reactivity ¼ f (knottiness, bond_elongation, valence_angle distortion).…”

Section: Introductionmentioning

confidence: 99%

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A grid-enabled algorithm yields figure-eight molecular knot

Psomopoulos

Mitkas

Krinas

et al. 2009

Molecular Simulation

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The recently proposed general molecular knotting algorithm and its associated package, MolKnot, introduce programming into certain sections of stereochemistry. This work reports the G-MolKnot procedure that was deployed over the grid infrastructure; it applies a divide-and-conquer approach to the problem by splitting the initial search space into multiple independent processes and, combining the results at the end, yields significant improvements with regards to the overall efficiency. The algorithm successfully detected the smallest ever reported alkane configured to an open-knotted shape with four crossings.

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Section: The Gmk Algorithmmentioning

confidence: 99%

Section: The Gmk Algorithmmentioning

confidence: 99%

Section: The Gmk Algorithmmentioning

confidence: 99%

Section: The Gmk Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A grid-enabled algorithm yields figure-eight molecular knot

Psomopoulos

Mitkas

Krinas

et al. 2009

Molecular Simulation

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Additional insights from very‐high‐resolution ¹³C NMR spectra of long‐chain n‐alkanes

Alemany

2013

Magnetic Reson in Chemistry

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New information has been obtained from very-high-resolution (13) C NMR studies of a series of long-chain n-alkanes. These compounds are fundamentally important in the petroleum industry and are essential to the life of some plants, flowers, and insects. At least partial resolution of the ten different (13) C NMR signals of n-C20 H42 is observed at 11.7 T for solutions in C6 D6 or C6 D5 CD3 . A (13) C T1 inversion-recovery experiment provides much more detailed information than in previous studies of long-chain n-alkanes, demonstrates a steady increase in the relaxation times of the ten different carbons proceeding from the middle to the end of the chain because of segmental motion, and thus confirms the assignments for the interior carbons. In contrast, there is significant overlap for the signals for C-7 and the more interior carbons in a solution of n-C16 or longer chain alkanes in CDCl3 . Not only are the chemical shifts sensitive to the solvent used, but also the relative chemical shifts change. Signals for the interior carbons of the odd-number alkanes in CDCl3 are better resolved than in the spectra of their even-number counterparts. Some mixed aromatic solvent systems give increased dispersion of the cluster of C-6 through C-10 signals of n-C20 H42 , n-C21 H44 , and n-C22 H46 . However, none of the solvents used could even partially resolve the C-10 and C-11 signals of n-C21 H44 or n-C22 H46 at 11.7 T, which may result from a different distribution of conformers for n-C21 H44 or n-C22 H46 than for n-C20 H42 and shorter n-alkanes.

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