244020-32-4Relevant academic research and scientific papers
Highly luminescent liquid crystals by connecting 1,3,4-oxadiazole with thiazolo[5,4-d]thiazole units
Bechtold, Ivan H.,Cazati, Thiago,Curcio, Sergio F.,Eccher, Juliana,Falc?o, Eduardo H. L.,Farias, Giliandro,Gallardo, Hugo,Girotto, Edivandro,Malvestiti, Ivani,Manfredi, Alex M.,Salla, Cristian A. M.,Santos, Arthur B. S.,Westphal, Eduard
, (2020/12/17)
The direct bonding between a thiazolo[5,4-d]thiazole and two 1,3,4-oxadiazole units allowed us to create a new and versatile rigid core for luminescent liquid crystal, which showed interesting and variable mesomorphic and photophysical properties. From the 5-bis(5-phenyl-1,3,4-oxadiazol-2-yl)thiazolo[5,4-d]thiazole new core, three molecules with different number of alkoxy chains were synthesized and had their properties correlated with the molecular structure. The molecule with two chains showed a smectic C mesophase, while the mesogens with four and six chains presented hexagonal columnar mesomorphism, which was confirmed by POM and XRD measurements. In addition, the molecule with six chains presented liquid crystalline behavior close to room temperature. In solution, the molecules presented strong photoluminescence ranging from blue to yellow, with quantum yields higher than 0.6. Excited state lifetimes allowed to correlate the fluorescence component associated to the different emitting species to the molecular organization in spin coated films. The molecular energy levels, together with thermal stability and possible charge carrier transport due to molecular packing, suggest that these molecules are promising for optoelectronic applications. Overall, this work contributes to the development of the use of thiazolo[5,4-d]thiazole in liquid crystals, demonstrating its great efficiency and versatility.
H-bonded complexes containing 1,3,4-oxadiazole derivatives: Mesomorphic behaviour, photophysical properties and chiral photoinduction
Vieira, Andre A.,Cavero, Emma,Romero, Pilar,Gallardo, Hugo,Serrano, Jose Luis,Sierra, Teresa
, p. 7029 - 7038 (2014/08/18)
Two series of new V-shaped acids derived from 1,3,4-oxadiazoles are described. These acids were used to prepare supramolecular complexes through hydrogen bonding with 2,4-diamino-6-dodecylamino-1,3,5-triazine in a 3:1 ratio, respectively. The formation of the complexes was studied by infrared and NMR techniques. The thermal behaviour and mesomorphic properties of all the complexes were investigated by polarized light optical microscopy, differential scanning calorimetry and X-ray diffraction. Hexagonal and rectangular columnar mesophases were observed for all complexes at room temperature, without evidence of crystallization. The results of circular dichroism studies allowed us to propose that in the liquid crystalline state these materials adopt a helical columnar organization and this chirality can be controlled by irradiation with CPL. Furthermore, the complexes display strong blue luminescence in solution and in the mesophase. the Partner Organisations 2014.
Liquid crystalline symmetrical 3,6-diaryl-1,2,4,5-tetrazines
Fouad, Farid,Ellman, Brett,Bunge, Scott,Miller, Patrik,Twieg, Robert
, p. 34 - 42 (2013/11/06)
A new series of symmetrical 3,6-diphenyl-1,2,4,5-tetrazines with four alkoxy tails were synthesized along with new examples with two alkoxy tails. Mesogenic properties were studied by differential scanning calorimetry and polarizing optical microscopy. Th
Luminescent columnar liquid crystals generated by self-assembly of 1,3,4-oxadiazole derivatives
Vieira, Andre A.,Gallardo, Hugo,Barbera, Joaquin,Romero, Pilar,Serrano, Jose Luis,Sierra, Teresa
supporting information; scheme or table, p. 5916 - 5922 (2011/12/03)
Five new V-shaped acids derived from 1,3,4-oxadiazole are described. These compounds were used to prepare supramolecular complexes via hydrogen bonding interactions with 2,4-diamino-6-dodecylamino-1,3,5-triazine in a 3:1 ratio. The formation of the comple
Bidirectional Association of Branched Noncovalent Complexes of Tetrazoles and 1,3,5-Tris(4,5-dihydroimidazol-2-yl)benzene in Solution
Kraft, Arno,Osterod, Frank,Froehlich, Roland
, p. 6425 - 6433 (2007/10/03)
Noncovalent 3:1 complexes were obtained by combining acidic tetrazoles with the tribasic 1,3,5-tris(4,5-dihydroimidazol-2-yl)benzene (1). A branched structure and the use of solubilizing groups ensured that the resulting complexes dissolved in a range of nonpolar organic solvents. An X-ray crystal structure analysis of a model complex with tetrazole showed a completely planar, C3-symmetrical, hydrogen-bonded molecule that salt-packed along the crystallographic c axis with an interplanar spacing of 3.31 A. Model binding studies between a tetrazolate and a protonated 1,3-bis(4,5-dihydroimidazol-2-yl)benzene allowed an association constant of 2470 ± 400 M-1 to be measured in the competitive solvent mixture CDCl3/CD3OD (97:3). The ionic nature and the extended planarity of the tetrazole complexes' core favored the formation of supramolecular stacks not only in the solid, but also in (nonpolar) solution. Self-association was evidenced by NMR and CD spectroscopy as well as by vapor-pressure osmometry.
