Consistencies between experiments and quantum calculations of strained C–C single bond lengths

Choi, Cheol Ho; Kertész, Miklós

doi:10.1039/a705439d

Cited by 31 publications

(22 citation statements)

References 12 publications

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“…Similar long bonds were also observed for other ethylene-bridged bianthracenes (Toyoda et al, 1985). High values were also found in theoretical calculations: 1.62-1.65 (Orimoto & Aoki, 2002), 1.64 (Zhou et al, 1993), 1.64-1.67 (Battersby et al, 1995) or 1.67-1.70 Å (Choi & Kertesz, 1997), depending on the basis sets.…”

Section: Compoundsupporting

confidence: 83%

Monitoring structural transformations in crystals. 12. Course of an intramolecular [4 + 4] photocycloaddition in a crystal

Trzop

Turowska‐Tyrk

2008

Acta Crystallogr B Struct Sci

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Variations in crystal and molecular structures, brought about by the intramolecular [4 + 4] photocycloaddition of bi(anthracene-9,10-dimethylene), were monitored using X-ray diffraction. The cell volume increased by 0.8% until the reaction was ca 40% complete, and afterwards decreased by 1.6% during the remainder of the photoreaction. The changes of the a and b lattice parameters were correlated with the changes of the molecular shape and packing. The distance between the directly reacting C atoms varied in a manner not observed for other photochemical reactions in crystals. It was constant until ca 20% photoreaction progress, then decreased, and later stabilized from ca 40% photoreaction progress. This phenomenon was explained by interplay between stress resulting from the presence of product molecules and the rigidity of reactant molecules. Changes of the orientation of molecules during the photoreaction were smaller than in the case of other monitored photochemical reactions in crystals owing to similarities in the shape and packing of reactant and product molecules. Weak C-H...pi hydrogen bonds exist among reactant molecules in the pure reactant and partly reacted crystals.

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Section: Compoundsupporting

confidence: 83%

Monitoring structural transformations in crystals. 12. Course of an intramolecular [4 + 4] photocycloaddition in a crystal

Trzop

Turowska‐Tyrk

2008

Acta Crystallogr B Struct Sci

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“…[40] This calculation suggests that the long bond in 59 is 1.667 Å . [41] Computations [B3LYP/dz(2d,p)] on 1,1,2,2-tetraphenylbenzocyclobutene (66), which is a suitable model for 13a, in a C 2 conformation similar to that found crystallographically for 13a predict a bond length of 1.708 Å , in excellent agreement with the experimental observation for 13a. Similar computations on 66 in a C 2v conformation predicted a still longer bond of 1.722 Å .…”

Section: Extremely Long C-c Bonds In Naphtho-and Phenanthrocyclobutensupporting

confidence: 64%

Naphthocyclobutenes and Benzodicyclobutadienes: Synthesis in the Solid State and Anomalies in the Bond Lengths

Toda¹

2000

Eur. J. Org. Chem.

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The title four‐membered ring compounds, naphthocyclobutenes and benzodicyclobutadienes, were produced by thermal cyclization reaction of crystalline 1,2‐diallenylbenzenes and 1,6‐diethynyldiallenes, respectively. These solid‐state reactions proceeded efficiently and stereoselectively. The naphthocyclobutenes were shown to have extremely long C (sp 3)‐C (sp 3) bonds (1.720−1.733 Å). The benzodicyclobutadienes were also shown to have extremely long C (sp 2)‐C (sp 2) bonds (1.540 Å).

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“…This functional has been shown to be reliable for the determination of normal and anomalous CC bond lengths using both 6‐31G(d) and 6‐31G(d,p) basis sets above 3g. 9 In a few cases (indicated in footnotes), a smaller basis set (6‐31G) was used. Frequency calculations were performed to confirm that every structure represents a true energy minimum.…”

Section: Methodsmentioning

confidence: 99%

Squeezing CC Bonds

et al. 2005

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It's not how short you make it, it's how you make it short! A diverse collection of compounds with short CC single bonds whose lengths range from 1.32 Å to 1.46 Å have been theoretically designed (see structure of a “spiderane”). The strategies for squeezing the CC bonds (encapsulation, strapping back, and stiffening) allow shorter bonds than hybridization and conjugative effects alone.

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Consistencies between experiments and quantum calculations of strained C–C single bond lengths

Cited by 31 publications

References 12 publications

Monitoring structural transformations in crystals. 12. Course of an intramolecular [4 + 4] photocycloaddition in a crystal

Monitoring structural transformations in crystals. 12. Course of an intramolecular [4 + 4] photocycloaddition in a crystal

Naphthocyclobutenes and Benzodicyclobutadienes: Synthesis in the Solid State and Anomalies in the Bond Lengths

Squeezing CC Bonds

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