Synthesis and electronic spectra of substituted bis(hexaphenylbenzenes)

Harvey, Janet; Ogliaruso, Michael A.

doi:10.1021/je60072a030

Cited by 5 publications

(4 citation statements)

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“…Thus, the Diels−Alder reaction of alkyl-substituted tetracyclone 5 with 4-iodo-4‘-dodecyldiphenylacetylene ( 4 ) in diphenyl ether affords hexaphenylbenzene derivative 6 in 30−70% yield, and subsequent oxidative dehydrogenation of 6 with iron(III) chloride provides 7 in good yield. Although Diels−Alder reactions of tetracyclones with diarylacetylenes to afford polyphenyl-substituted aromatic hydrocarbons have been reported many times, ,− in our hands, it was observed that the yield of 6 was highly variable. Careful study of this reaction showed that the yield varied strongly with temperature.…”

Section: Resultsmentioning

confidence: 54%

Photophysics of Platinum−Acetylide Substituted Hexa-peri-hexabenzocoronenes

et al. 2006

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This manuscript reports the synthesis and photophysical investigation of two hexa-peri-hexabenzocoronenes (HBCs) that are functionalized with platinum(II) acetylide units of the type trans-(Ar-CC-)2Pt(PBu3)2. In one complex, the platinum is directly linked to the HBC chromophore by an ethynyl spacer, whereas in the second, the platinum is separated from the HBC via a 1,4-phenylene ethynylene spacer. The Pt-acetylide units introduce strong spin-orbit coupling into the HBC chromophore, giving rise to high yields of the triplet excited state along with moderately intense phosphorescence at ambient temperature. On the basis of emission spectroscopy, the triplet state of the HBC chromophore is located at 2.14 eV and the S-T splitting is 0.6 eV. The triplet-triplet absorption and radical cation absorption spectra of the Pt-HBCs are determined by laser flash photolysis. Aggregation of the Pt-HBCs in a poor solvent such as hexane leads to quenching of the triplet state, but spectroscopy provides no evidence for the formation of a triplet excimer, even under conditions where the molecules are strongly aggregated.

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Section: Resultsmentioning

confidence: 54%

Photophysics of Platinum−Acetylide Substituted Hexa-peri-hexabenzocoronenes

et al. 2006

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“…In another report studying the effect of substitutions on HAB derivatives, Harvey and Ogliaruso 43 compared absorption properties of HPB and bis(hexaphenylbenzenes) (BHPBs) 5− 7 (Figure 3). It was observed that the absorption spectra of the substituted derivatives shift to slightly longer wavelength accompanied by a decrease in molar extinction coefficients in comparison to the corresponding unsubstituted derivatives.…”

Section: Synthetic and Structural Optimization Of Hpbmentioning

confidence: 99%

Hexaarylbenzene: Evolution of Properties and Applications of Multitalented Scaffold

2016

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The easily rotatable peripheral aromatic rings around central benzene in hexaarylbenzene (HAB) derivatives create a very intriguing nonplanar, propeller-shaped geometry. Because of the very low susceptibility toward self-aggregation, HAB derivatives are much stronger candidates among various polyphenylenes/hetero-oligophenylenes when poor molecular cohesion and inefficient packing is required. However, the native properties of hexaphenylbenzene (HPB) can be varied by proper tailoring and substitution of the HAB core. The cohesion and packing in the structures of HAB aggregates induce effective structural variations so as to modify the fundamental features. Recently, HAB derivatives attracted a lot of research interest because of their significant role as liquid crystalline materials, organic light-emitting diodes, photochemical switches, redox materials, and molecular receptors. Herein, detailed attention is given to the pioneering work based on synthetic optimization of different HAB cores, elaborated study of their crystal engineering, various interesting applications of HAB derivatives, and future possibilities and capabilities of this still underexplored scaffold.

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“…These could then serve as precursors for large, all-benzenoid hydrocarbons with varying topology. Oligaruso [149][150][151] and Ried, [152][153][154][155] who prepared a multitude of unsubstituted oligophenylenes in the 1960s, must count among the pioneers in the synthesis of extended, 2-dimensional oligophenylenes by Diels-Alder reaction of tetraphenylcyclopentadienone (80) with suitable 1,2-diphenylethyne systems.…”

Section: The Intermolecular [4+2]-cycloaddition Of Tetraphenylcyclope...mentioning

confidence: 99%

“…These could then serve as precursors for large, all-benzenoid hydrocarbons with varying topology. Oligaruso − and Ried, − who prepared a multitude of unsubstituted oligophenylenes in the 1960s, must count among the pioneers in the synthesis of extended, 2-dimensional oligophenylenes by Diels−Alder reaction of tetraphenylcyclopentadienone ( 80 ) with suitable 1,2-diphenylethyne systems. Since 1986, Pascal et al employed a series of cyclopentadienone derivatives together with various ethyne and aryne compounds in a [4+2]-cycloaddition reaction to produce twisted polycyclic aromatic hydrocarbons. − Compounds such as 83 , 85 , or the albatrossenes such as 88 , all containing oligophenylene as well as oligoacene motifs, became accessible (Schemes 20−22).…”

Section: The Intermolecular [4+2]-cycloaddition Of Tetraphenylcyclope...mentioning

confidence: 99%