3073-05-0Relevant academic research and scientific papers
Synthesis of cyclopentadienyl iron complexes with substituted phenylene ligands via Suzuki coupling
Shved, Andrei M.,Nelyubina, Yulia V.,Perekalin, Dmitry S.
, (2020)
Cationic cyclopentadienyl iron complexes of substituted phenylenes [CpFe(p-CH3-C6H4-Ar)]PF6 and [CpFe(p-Ar-C6H4-Ar)]PF6 were obtained in 37–73% yields by Pd-catalyzed Suzuki coupling reactions of [CpFe(p-CH3-C6H4-Cl)]PF6 and [CpFe(p-Cl-C6H4-Cl)]PF6 with polyarylboronic acids Ar-B(OH)2 (Ar = biphenyl, naphthyl, phenanthryl, bithienyl). The complex [CpFe(p-CH3-C6H4-Cl)]PF6 also underwent Sonogashira-type coupling with phenylacetylene to give the compound [CpFe(p-CH3-C6H4-C[tbnd]C-Ph]PF6 in 26% yield. Such coupling reactions represent an alternative approach to [CpFe(arene)]PF6 complexes, which are typically obtained from ferrocene via Bolesova-Nesmeyanov reaction under harsh conditions (AlCl3, >100 °C). The structures of the products of Suzuki reaction were established by single-crystal X-ray diffraction analysis.
Calculated and experimental uv and ir spectra of oligo-para-phenylenes
Park, Kwangyong,Lee, Tae-Won,Yoon, Min-Ju,Choe, Jong-In
, p. 531 - 538 (2014/03/21)
The quantum mechanical properties of a series of oligo-para-phenylenes (2-11) were characterized using DFT B3LYP/6-311G(d,p) calculations. The global minimum among the various torsional conformers of an oligo-pphenylene is calculated to be a twist conformation. A less stable planar conformation, in which all the dihedral angles in oligo-p-phenylene are restricted to be planar, has also been calculated. The total electronic energies, normal vibrational modes, Gibbs free energies, and HOMOs and LUMOs of the two different conformations (twisted and planar) of the oligo-p-phenylenes were analyzed. The energy differences between the HOMOs and LUMOs of the substrates are in accord with the maximum absorption peaks of the experimental UV spectra of 2-6. The calculated normal vibrational modes of 2-6 were comparable with their experimental IR spectra.
Synthesis of p-Quinquephenyl from E,E-1,4-Bis(4-bromophenyl)-1,3-butadiene
Davis, Matthew C.,Groshens, Thomas J.
, p. 206 - 218 (2011/03/18)
p-Quinquephenyl was synthesized in five steps from E,E-1,4-bis(4- bromophenyl)-1,3-butadiene in 34% overall yield. The butadiene was prepared in six steps from 4-bromobenzaldehyde in 35% overall yield. Copyright Taylor & Francis Group, LLC.
Synthesis of penta-p-phenylenes with oligo(ethylene glycol) side chains
López-Romero, J. Manuel,Rico, Rodrigo,Martínez-Mallorquín, Rocío,Hierrezuelo, Jesús,Guillén, Elena,Cai, Chengzhi,Otero, J. Carlos,López-Tocón, Isabel
, p. 6075 - 6079 (2008/03/12)
We report an efficient synthesis of a series of penta-p-phenylene derivatives with four side chains of various lengths, including deca(ethylene glycol) groups. The key feature of the synthesis is that the side chains are efficiently introduced in the last step, facilitating optimization of the side chains for different applications. Raman spectroscopy study indicates a similarly high rigidity for all these compounds, even those with long oligo(ethylene glycol) side chains. The deca(ethylene glycol)-substituted penta-p-phenylene derivatives are versatile building blocks for construction of nanometric, tripod-shaped adsorbates for biological applications.
Javelin-, hockey stick-, and boomerang-shaped liquid crystals. Structural variations on p-quinquephenyl
Dingemans, Theo J.,Murthy, N. Sanjeeva,Samulski, Edward T.
, p. 8845 - 8860 (2007/10/03)
The ramifications of changing molecular geometry in a series of all-aromatic liquid crystals derived from p-quinquephenyl are reported. Substituting heterocyclic rings such as thiophene, oxadiazole, oxazole, or 1,3-phenylene into the p-quinquephenylene core affects molecular shape changes via the substituent's exocyclic bond angle. In general, we found that introducing nonlinearity into molecules depresses the melting transition temperature. The symmetric (boomerang-shaped) molecules, 2,5-bisbiphenyl-4-yl-1,3,4-oxadiazole, 2,5-bisbiphenyl-4-yl-oxazole, and 1,3-bisbiphenyl-4-yl-benzene, melt into isotropic phases showing small monotropic mesophases. By contrast, the asymmetric (hockey stick-shaped) mesogens, 2-terphenyl-4-yl-5-phenyl thiophene and 2-terphenyl-4-yl-5-phenyl-1,3,4-oxadiazole, exhibit more stable enantiotropic liquid crystalline phases. The hockey stick-shaped mesogens exhibit a smectic phase as well as a nematic phase. High-temperature X-ray determination of the smectic layer spacing gives an unambiguous picture of interdigitated, bilayerlike supramolecular architecture in the smectic phase. There are associated changes in the mesogen's electrostatic profile when a heterocycle is introduced into the quinquiphenylene framework (e.g., conjugation is perturbed). Our findings suggest that steric packing considerations dominate the phase preferences (nematic versus smectic phases). However, electronic considerations (conjugation) appear to control the range of mesomorphism in this new family of nonlinear liquid crystals.
One Pot Synthesis of p-Polyphenyls via the Intramolecular Cyclization of 3-Dimethylaminohex-5-en-1-ynes
Unroe, Marilyn R.,Reinhardt, Bruce A.
, p. 981 - 986 (2007/10/02)
Para linked polyphenyls of various molecular weights are conveniently synthesized from p-bis(3-dimethylamino-1-propynyl)arenes and 1-aryl-2-propenyl bromides in moderate yields using a three step, one-pot procedure.
Synthetically Useful Aryl-Aryl Bond Formation via Grignard Generation and Trapping of Arynes. A One Step Synthesis of p-Terphenyl and Unsymmetric Biaryls
Hart, Harold,Harada, Katsumasa,Du, Chi-Jen Frank
, p. 3104 - 3110 (2007/10/02)
A one-pot route to p-terphenyls is described.Addition of 1,4-dibromo-2,5-diiodobenzene, 1, to excess aryl Grignard reagent gives the terphenyl di-Grignard 2 and the trihalo mono-Grignard 5.After aqueous quench, p-terphenyls are isolated in 30percent to 50percent yield (Table I).This yield can be improved to 70-80percent by adding potassium tert-butoxide or lithium tetramethylpiperidide to the reaction mixture prior to workup.Mechanisms involving organometallic aryne intermediates are proposed.With o-bromoiodoarenes in place of tetrahaloarenes the method can be adapted to prepare unsymmetric biaryls in good yield (Table II).
A NEW SYNTHESIS OF PARA-TERPHENYLS
Hart, Harold,Harada, Katsumasa
, p. 29 - 32 (2007/10/02)
A new, one-step synthesis of para-terphenyls from aryl Grignards and 1,4-dibromo-2,5-diiodobenzene 1 as a di-aryne equivalent is described.
