The structure of hexaphenylbenzene anisole clathrate, 2C6(C6H5)6.C6H5OCH3

Larson, E. M.; Dreele, Robert B. Von; Hanson, Paul R.; Gust, J.D.

doi:10.1107/s0108270189007444

Cited by 248 publications

(272 citation statements)

References 3 publications

(3 reference statements)

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“…At first sight, all of the three hexaphenylbenzene units merged with the common TBTQ core are oriented in similar conformations, which, as a first approximation, result in a C 3 -symmetrical overall conformation for the mol- . [46] However, closer inspection of the structure reveals that one of the PPP groupings of 4, which comprises the biphenyl group BЈ-BЈЈ attached at C6, is oriented more steeply towards the concave face of the TBTQ core. The dihedral angle of the corresponding "inner" biaryl unit, Є{B}-{BЈ}, is 91.0(1)°, whereas the dihedral angles of the corresponding other inner biaryl units, are much smaller, Є{A}-{AЈ} = 59.6(1)°and Є{C}-{CЈ} = 66.5(1)°.…”

Section: Resultsmentioning

confidence: 99%

Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core

et al. 2014

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The synthesis of tribenzotriquinacenes (TBTQs) that bear three phenylethynyl groups at the peripheral positions of the bowl-shaped molecular scaffold has been achieved by use of different strategies. Although the C 1 -and C 3 -symmetrical triformyl, triethynyl and triiodo derivatives were inseparable by chromatography, the corresponding C 1 -and C 3 -symmetrical tris(phenylethynyl)tribenzotriquinacenes were obtained

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Section: Resultsmentioning

confidence: 99%

Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core

et al. 2014

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“…These large splittings suggest that rotation about the two single bonds in the phenyl linkage between the porphyrin macrocycle and the benzene ring at the core of the hexaphenylbenzene scaffold (labeled a and b in Scheme 4) is slow on the NMR time scale at ambient temperatures. This is not unexpected, as the dihedral angles between the phenyl rings in this linkage are large (typically 65-90º [43][44][45]), indicating signifi cant steric hindrance that precludes a planar conformation. To verify this possibility, 1 H NMR spectra were measured at various temperatures in toluene-d 8 .…”

Section: Nmr Investigation and Restricted Rotationmentioning

confidence: 81%

Artificial photosynthetic antenna-reaction center complexes based on a hexaphenylbenzene core

Terazono

Liddell

Garg

et al. 2005

J. Porphyrins Phthalocyanines

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A hexaphenylbenzene scaffold has been used to organize the components of artifi cial photosynthetic antennas and antenna-reaction center mimics that feature bis(phenylethynyl)anthracene antenna moieties and porphyrin-fullerene charge-separation units. The fi ve bis(phenylethynyl)anthracene chromophores absorb in the spectral region around 430-480 nm, where porphyrins have low extinction coeffi cients but solar irradiance is maximal. The hexaphenylbenzene core was built up by the well-known Diels-Alder reaction of diarylacetylenes with substituted tetraphenylcyclopentadienones. The latter were in turn prepared by condensation of substituted benzils and dibenzyl ketones, allowing fl exibility in the design of the substitution pattern on the core. The spacing between the various chromophores is suitable for rapid singlet-singlet energy transfer among antenna moieties and the porphyrin, and the relatively rigid structure of the hexaphenylbenzene limits conformational heterogeneity that could reduce the effi ciency of energy and electron transfer. NMR studies reveal a high barrier to rotation of the porphyirn plane relative to the hexaphenylbenzene.

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“…The packing is a distorted body-centered cubic lattice typical for the crystallization of solid spheres. 34 In contrast, in cases of severe steric encumbrance such as 3,3=,5,5=-tetrakis(pentaphenylphenyl)biphenyl (20), the phenyl orientations range from 26°to 89°. 34 However, the average of these 24 dihedral angles is 66°, again showing how the molecules adjust their conformations to find the minimum energy structure.…”

Section: Correlation Of Ortho and Para Phenyl Twist Anglesmentioning

confidence: 92%

“…20 However, more recent reports by Spek (21a) and by Munakata (21b) revealed that in hexaphenylbenzene itself, the dihedral angles ranged from 65°to 89°(average 79.5°). In the symmetrical polyaryl system 4,4=,4==,4ٞ-tetrakis(pentaphenylphenyl)tetraphenylmethane, (p-C 6 Ph 5 -C 6 H 4 ) 4 C (19), which effectively contains four hexaphenylbenzene units, the peripheral phenyls adopt an almost ideal propeller conformation with somewhat smaller twist angles of 64°± 2°.…”

Section: Correlation Of Ortho and Para Phenyl Twist Anglesmentioning

confidence: 95%

Organic and organometallic derivatives of pentaphenylbenzene, C₆Ph₅X: correlation of peripheral phenyl ring orientations with the steric bulk of “X”

et al. 2013

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A series of C 6 Ph 5 X compounds, including X = H, Br, CO 2 H, CO 2 R, C'CPh, cis-BrC=C(Br)Ph, 2-bornenyl, and ferrocenyl, have been characterized by use of X-ray crystallography. Also, the first organometallic complexes of pentaphenylbenzene have been prepared by reaction with chromium hexacarbonyl to yield ( 6 -C 6 Ph 5 H)Cr(CO) 3 complexes in which the metal tripod is attached either to an ortho peripheral ring or to the central ring. Crystalline pentaphenylbenzoic acid exists as a hydrogenbonded dimer; however, the steric bulk of the substituents does not allow the carboxylic acid moieties to be linked directly but instead via two bridging methanol molecules. In the solid state, the orientation of the peripheral rings in bulky C 6 Ph 5 X systems is very sensitive to the size of the "X" substituents, such that the twist angle of the para ring responds inversely with increasing bulk of "X", which drives the ortho rings farther out of the plane of the central ring. The relevance of these observations to correlated motion in molecular propellers, and ultimately to molecular machines, is discussed.Résumé : À l'aide de la cristallographie aux rayons X, on a caractérisé une série de composés de formule C 6 Ph 5 X, où X = H, Br, CO 2 H, CO 2 R, C'CPh, cis-BrC=C(Br)Ph, 2-bornényl et ferrocényl. En outre, on a préparé les premiers complexes organométal-liques du pentaphénylbenzène en le faisant réagir avec de l'hexacarbonyle de chrome pour obtenir les complexes ( 6 -C 6 Ph 5 H)Cr(CO) 3 dans lesquels le tripode métallique est attaché à un noyau périphérique en ortho ou au noyau central. L'acide pentaphénylbenzoïque existe à l'état de dimère formé par liaisons hydrogènes; toutefois, l'encombrement stérique des substituants ne permet pas la liaison directe des groupements carboxyliques qui sont plutôt reliés par un pont constitué de deux molécules de méthanol. À l'état solide, l'orientation des noyaux périphériques dans les volumineux systèmes C 6 Ph 5 X est très sensible à la taille des substituants « X », de sorte que l'angle de torsion du noyau en para répond inversement à l'encombrement croissant de « X » qui repousse de plus en plus les noyaux en ortho hors du plan du noyau central. Une discussion de l'intérêt de ces observations en ce qui concerne le mouvement corrélé dans les hélices moléculaires, et en bout de ligne les machines moléculaires, est offerte. [Traduit par la Rédaction]

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The structure of hexaphenylbenzene anisole clathrate, 2C6(C6H5)6.C6H5OCH3

Cited by 248 publications

References 3 publications

Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core

Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core

Artificial photosynthetic antenna-reaction center complexes based on a hexaphenylbenzene core

Organic and organometallic derivatives of pentaphenylbenzene, C₆Ph₅X: correlation of peripheral phenyl ring orientations with the steric bulk of “X”

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The structure of hexaphenylbenzene anisole clathrate, 2C6(C6H5)6.C6H5OCH3

Cited by 248 publications

References 3 publications

Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core

Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core

Artificial photosynthetic antenna-reaction center complexes based on a hexaphenylbenzene core

Organic and organometallic derivatives of pentaphenylbenzene, C6Ph5X: correlation of peripheral phenyl ring orientations with the steric bulk of “X”

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Organic and organometallic derivatives of pentaphenylbenzene, C₆Ph₅X: correlation of peripheral phenyl ring orientations with the steric bulk of “X”