The crystal structure of 2,7-di-<i>t</i>-butylpyrene

Hazell, Alan; Lomborg, J. G.

doi:10.1107/s0567740872003711

Cited by 16 publications

(18 citation statements)

References 5 publications

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“…The 1 H NMR spin-lattice relaxation experiments have been previously reported for 2, 24 3, 25 and 4. 23 The crystal structures have been reported elsewhere for all four compounds: 1, 27 2, 28 25,29 and 4. 23 It is the intermolecular interactions that present the computational challenge in this study.…”

Section: Fig 1 Schematic Pictures Of the Four Compounds Investigatementioning

confidence: 99%

“…They were constructed from the single-crystal X-ray diffraction data. The reference codes in the Cambridge Crystallographic Structural Database are BUTPYR10 for 1 27 BUTBNZ for 2, 28 KOKQUW for polymorph A of 3, 25,29 and QEFBAE for 4. 23 The clusters consist of 9-14 molecules and are sufficiently large to include the significant intermolecular interactions between the target t-butyl group and the surrounding molecules (as discussed further in Sec.…”

Section: Electronic Structure Calculations In the Clustersmentioning

confidence: 99%

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Solid state 1H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: The relationship between structure and methyl group and t-butyl group rotation

Wang

Mallory

et al. 2014

The Journal of Chemical Physics

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Solid state 1H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: The relationship between structure and methyl group and t-butyl group rotation. X Wang, F B Mallory, C W Mallory, H R Odhner,* and P A Beckmann 2014 J Chem Phys 140 194304 1-15.Solid state 1H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: The relationship between structure and methyl group and t-butyl group rotation We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state 1 H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl group rotation in a central target molecule in the cluster with the activation energies determined from fitting the 1 H NMR spin-lattice relaxation data. We formulate a dynamical model for the superposition of t-butyl group rotation and the rotation of the t-butyl group's constituent methyl groups. The four compounds are 2,7-di-tbutylpyrene, 1,4-di-t-butylbenzene, 2,6-di-t-butylnaphthalene, and 3-t-butylchrysene. We comment on the unusual ground state orientation of the t-butyl groups in the crystal of the pyrene and we comment on the unusually high rotational barrier of these t-butyl groups. © 2014 AIP Publishing LLC. [http://dx

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Section: Fig 1 Schematic Pictures Of the Four Compounds Investigatementioning

confidence: 99%

Section: Electronic Structure Calculations In the Clustersmentioning

confidence: 99%

Solid state 1H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: The relationship between structure and methyl group and t-butyl group rotation

Wang

Mallory

et al. 2014

The Journal of Chemical Physics

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“…[13] These bonds are elongated for the fused systems by about 0.02-0.03 .T he length of the connectingb ond of the central biphenyl unit in the parents ystem is 1.42 ,w hich is comparable to those of bisacyl 2 (1.42 )a nd monopyridazine 4 (1.42 ). The peripheral bonds are on average alwayss horter than the inner,f used bonds.…”

Section: Resultsmentioning

confidence: 94%

“…However,f or In the structures with fused five-membered rings, the lengths of the inner bonds are about 1.44-1.45 for the mono-fused compounds 3a-3c and even 1.47 and 1.48 for bis-fused pyrenes 7a and 7b.U nsurprisingly,t he lengths of the fused K-edges in 3a-3c and 7a, 7b are between 1.44 and 1.49 ,and suggest that no more olefinic character remains. Crystal structures of 2,7-di-tert-butyl-pyrene [13] and compounds 2-4 (colorc ode C: gray, O: red, S: yellow,N:blue). These data suggest that the p-electrons are somewhat localized and the interaction between them is smaller than in typical fused systems.…”

Section: Resultsmentioning

confidence: 99%

“…In the parents ystem,t he [d]-, [f]-, [k]-, and [m]-bond lengthsa re between 1.43 and 1.44 . [13] These bonds are elongated for the fused systems by about 0.02-0.03 .T he length of the connectingb ond of the central biphenyl unit in the parents ystem is 1.42 ,w hich is comparable to those of bisacyl 2 (1.42 )a nd monopyridazine 4 (1.42 ). However,f or tetraacyl compound 6 and bis-pyridazine 8 thesec entral bonds are somewhat longer(1.44 and 1.45 ,r espectively).…”

Section: Introductionmentioning

confidence: 94%

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K‐Region‐Extended [c]‐Heteroannulated Pyrenes

Baumgärtner

Kirschbaum

Krutzek

et al. 2017

Chemistry A European J

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Extended fused aromatic compounds are promising materials for organic electronics. Among them, structures with five-membered annulated rings differ from those consisting only of six-membered carbocyclic rings. To date, fusion of five-membered rings has been realized mainly via the [b]-edge, and systems fused via the [c]-edge are of low stability. Whereas linearly double [b]-fused systems are stable, analogous [c]-fused systems have not been described to date. Comparable to the stabilization of longer acenes by peri-fusion, herein the synthesis of doubly [c]-annulated systems stabilized by double peri-fusion is described. The compounds were analyzed by X-ray crystallography, photophysical methods, and DFT calculations to gain deeper insight into the nature of conjugation in these new systems.

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