20199-19-3Relevant articles and documents
Preparation of and dynamic gearing in cis-1,2-bis(9-triptycyl)ethylene
Kawada, Yuzo,Sakai, Hiromi,Oguri, Makoto,Koga, Gen
, p. 139 - 142 (1994)
The two tortional degrees of freedom about the bond from the bridgehead to the olefinic carbons in cis-1,2-bis(9-triptycyl)ethylene couple slightly less strongly than those in the corresponding methane in spite of the apparently deeper meshing of the two triptycyl moiety, which manifests itself in the unusually large nuclear spin-spin coupling between the olefinic protons.
A non-planar crystal polymorph of 1,2-bis(9-anthracenyl)ethyne
Eichler, Barrett,Erickson, Jeremy,Keppen, Joseph,Sykes, Andrew,Sereda, Grigoriy
, p. 4574 - 4577 (2015)
1,2-Bis(9-anthracenyl)ethyne was synthesized and a new crystal polymorph was discovered. The previously reported structure was completely planar with a torsional angle between the two anthracenyl rings of 0.0°, whereas the new polymorph had a torsional angle of 66.6°. The new polymorph also stacks differently between molecules and has greater π-electron overlap. In solution, the spectroscopic characteristics of both polymorphs were identical, but in the solid-state, results of red-shifted spectra for the co-planar polymorph indicate a strikingly simple example of the effect on UV-vis and fluorescence spectra of extending π-conjugation wrapped up in one molecule with two polymorphs. It was also determined that the co-planar polymorph is favored with rapid crystallization, whereas the twisted polymorph prefers slow crystallization. This may indicate that the co-planar polymorph is kinetically favored and the twisted polymorph is thermodynamically favored.
Photophysical properties of symmetrically substituted diarylacetylenes and diarylbuta-1,3-diynes
Bylińska, Irena,Wierzbicka, Ma?gorzata,Czaplewski, Cezary,Wiczk, Wies?aw
, p. 45 - 56 (2016/01/20)
A series of symmetrically substituted diarylacetylenes and diaryl-1,3-butadiynes were prepared and studied with an emphasis on their spectral and photophysical properties. The photophysical characteristics of these compounds were studied in relation to their structures and the influence of solvent or temperature. The observed spectral and photophysical properties are explained using potential energy maps of the ground and excited states obtained from density functional theory calculations. The structure-property relationships of all of the compounds are discussed and compared with the appropriate diphenylacetylene and diphenyl-1,3-butadiyne derivatives.
Dynamics of the formation of a charge transfer state in 1,2-bis(9-anthryl)acetylene in polar solvents: Symmetry reduction with the participation of an intramolecular torsional coordinate
Gutieì?rrez-Arzaluz, Luis,Guarin, Cesar A.,Rodriì?guez-Coì?rdoba, William,Peon, Jorge
, p. 12175 - 12183 (2013/11/06)
We have studied 1,2-bis(9-anthryl)acetylene as a model compound for the characterization of the process of solvent-mediated symmetry reduction in an excited state. Thanks to the acetylenic bridge that joins the two anthracenic moieties, this system maintains minimal steric hindrance between the end chromophores in comparison with the classic 9,9a?2-bianthryl model compound. The acetylenic bridge also allows for significant electronic coupling across the molecule, which permits a redistribution of electron density after light absorption. Femtosecond resolved fluorescence measurements were used to determine the spectral evolution in acetonitrile and cyclohexane solutions. We observed that, for 1,2-bis(9-anthryl)acetylene, the formation of a charge transfer state occurs in a clear bimodal fashion with well separated time scales. Specifically, the evolution of the emission spectrum involves a first solvent-response mediated subpicosecond stage where the fluorescence changes from that typical of nonpolar solvents (locally excited) to an intermediate, partial charge transfer state. The second stage of the evolution into a full charge transfer state occurs with a much longer time constant of 37.3 ps. Since in this system the steric hindrance is minimized, this molecule can undergo much larger amplitude motions for the torsion between the two anthracenic moieties associated with the charge redistribution in comparison with the typical model compound 9,9a?2-bianthryl. Clearly, the larger range of motions of 1,2-bis(9-anthryl)acetylene gives the opportunity to study the electron transfer process with a good separation of the time scales for the formation of a partial charge transfer state, determined by the speed of solvent response, and the intramolecular changes associated with the formation of the fully equilibrated charge transfer state. ? 2013 American Chemical Society.
Photonic amplification by a singlet-state quantum chain reaction in the photodecarbonylation of crystalline diarylcyclopropenones
Kuzmanich, Gregory,Gard, Matthew N.,Garcia-Garibay, Miguel A.
supporting information; experimental part, p. 11606 - 11614 (2011/03/17)
The photochemical decarbonylation of diphenylcyclopropenone (DPCP) to diphenylacetylene (DPA) proceeds with remarkable efficiency both in solution and in the crystalline solid state. It had been previously shown that excitation to the second electronic excited state (S2) of DPCP in solution proceeds within ca. 200 fs by an adiabatic ring-opening pathway to yield the S2 state of DPA, which has a lifetime of ca. 8 ps before undergoing internal conversion to S1 (Takeuchi, S.; Tahara, T. J. Chem. Phys. 2004, 120, 4768). More recently, we showed that reactions by excitation to S2 in crystalline solids proceed by a quantum chain process where the excited photoproducts transfer energy to neighboring molecules of unreacted starting material, which are able to propagate the chain. Quantum yields in crystalline suspensions revealed values of ΦDPCP = 3.3 = 0.3. To explore the generality of this reaction, and recognizing its potential as a photonic amplification system, we have synthesized nine crystalline diarylcyclopropenone derivatives with phenyl, biphenyl, naphthyl, and anthryl substituents. To quantify the efficiency of the quantum chain in the crystalline state, we determined the quantum yields of reaction for all of these compounds both in solution and in nanocrystalline suspensions. While the quantum yields of decarbonylation in solution vary from Φ = 0.0 to 1.0, seven of the nine new structures display quantum yields of reaction in the solid that are above 1. The chemical amplification that results from efficient energy transfer in the solid state, analyzed in terms of the quantum yields determined in the solid state and in solution (Φcryst/Φsoln), reveals quantum chain amplification factors that range from 3.2 to 11.0. The remarkable mechanical response of the solid-to-solid reaction previously documented with macroscopic crystals, where large single-crystalline specimens turn into fine powders, was investigated at the nanometer scale. Experiments with dry crystals of DPCP analyzed by atomic force microscopy showed the formation of DPA in the form of isolated crystalline specimens ca. 35 nm in size.
Chemistry of anthracene-acetylene oligomers. XIV. convenient synthesisof anthrylethynes by double elimination reaction from aldehydes and sulfones
Toyota, Shinji,Azami, Rie,Iwanaga, Tetsuo,Matsuo, Daisuke,Orita, Akihiro,Otera, Junzo
experimental part, p. 1287 - 1291 (2010/01/30)
Three dianthrylethynes and an anthracene-acetylene trimer were conveniently synthesized by doubleelimination reactions starting from anthraldehydes and [(phenylsulfonyl)methyl]anthracenes. In the optimal one-shot process, a THF solution of these substrate
Alkyne metathesis with simple catalyst systems: High yield dimerization of propynylated aromatics; scope and limitations
Pschirer, Neil Gregory,Bunz, Uwe H. F.
, p. 2481 - 2484 (2007/10/03)
High yield dimerization of propynylated benzenes and propynylnaphthalene by a mixture of Mo(CO)6 and 4-chlorophenol at 140 °C in 1,2-dichlorobenzene is reported to give the corresponding disubstituted alkynes. The scope and limitation of the reaction and the influence of substitution pattern and substitution type are discussed. Oxygen or nitrogen carrying substrates metathesize in moderate to good yields and ortho-alkyl substituted examples form the respective tolanes very efficiently.
On the Relationship between Molecular Geometry and Photochemical Properties of 1,2-Substituted 1,2-Di-9-anthrylethylenes
Becker, Hans-Dieter,Andersson, Kjell
, p. 5205 - 5213 (2007/10/02)
Starting from either 1,2-di-9-anthrylethanone or di-9-anthrylcyclopropenone, a series of cis-trans isomeric 1,2-di-9-anthrylethylenes substituted at the central ethylene bond has been synthesized, and their photochemical properties in terms of geometric isomerization and intramolecular cycloaddition have been investigated.By substitution of the ethylene bond with methoxy and methyl, the quantum yields of both photochemical trans->cis isomerization and intramolecular cycloaddition of the cis isomers are greatly increased.Substituents such as formyl and methoxycarbonyl apparently enhance intersystem crossing so as to induce isomerization by cycloaddition.Photochemical isomerization of 1,2-di-9-anthryl-1-hydroxypropene proceeds by hydrogen shift and results in the dearomatization of one anthracene moiety.Monosubstituted cis-dianthrylethylenes in solution are nonfluorescent.The fluorescence of cis-1-methoxy-2-methyl-1,2-di-9-anthrylethylene is suggested to originate from an intramolecular excimer state.For the corresponding trans isomer, the fluorescence is found to be dependent on solvent polarity as is typical of a twisted intramolecular charge-transfer state.
NOVEL POLYCYCLIC AROMATIC HYDROCARBONS BY INTRAMOLECULAR DIELS-ALDER REACTION: FROM LEPIDOPTERENES TO BENZENOBENZOPENTAPHENES VIA DIANTHRYLETHANES
Becker, Hans-Dieter,Andersson, Kjell
, p. 1555 - 1560 (2007/10/02)
A series of mono-substituted lepidopterenes has been synthesized, and the effect of the substituent (methyl, formyl, cyano, benzoyl) on the 4+2 cycloreversion has been studied.Benzoyllepidopterene was thermally converted into benzoyldianthrylethane whose
