Xn:Harmful;16278-99-2Relevant articles and documents
Influence of substitution pattern and enhanced π-conjugation on a family of thiophene functionalized 1,5-dithia-2,4,6,8-tetrazocines
Magnan, Fran?ois,Korobkov, Ilia,Brusso, Jaclyn
, p. 7272 - 7280 (2015/09/02)
A versatile, one-pot synthetic route to prepare a series of 1,5,2,4,6,8-dithiatetrazocines (DTTA) functionalized with 4-hexylthiophen-2-yl, 5-(thiophen-2′-yl)thiophen-2-yl and 5-(5′-hexylthiophen-2′-yl)thiophen-2-yl is described. The latter two compounds mark the first reported examples of π-extended DTTA systems. Comparative spectroscopic, computational and structural studies were carried out on this family of heterocycles to investigate the influence of the substitution pattern, in addition to enhanced conjugation, on the optoelectronic and solid-state properties. These studies revealed a slight increase in the optical energy gap upon displacement of the alkyl chain from the 5- to the 4-position in hexylthienyl functionalized DTTA, whereas extension of the conjugation diminishes the HOMO-LUMO gap. In the solid-state, variation in alkyl substituent plays an important role, contrary to what was previously observed for aryl functionalized DTTA derivatives.
Effect of substituents on redox, spectroscopic and structural properties of conjugated diaryltetrazines - A combined experimental and theoretical study
Kurach, Ewa,Djurado, David,Rimarik, Jan,Kornet, Aleksandra,Wlostowski, Marek,Luke, Vladimir,Pecaut, Jacques,Zagorska, Malgorzata,Pron, Adam
experimental part, p. 2690 - 2700 (2011/09/20)
Two series of new soluble conjugated compounds containing tetrazine central ring have been synthesized. The three-ring compounds have been synthesized by the reaction of aryl cyanide (where aryl = thienyl, alkylthienyl, phenyl or pyridyl) with hydrazine followed by oxidation of the intermediate product with diethyl azodicarboxylate. The five-ring compounds have been prepared using two pathways: (i) reaction of 5-cyano-2,2′-bithiophene (or its alkyl derivative) with hydrazine; (ii) via Suzuki or Stille coupling of 3,6-bis(5-bromo-2-thienyl)-1,2,4,5-tetrazine with a stannyl or boronate derivative of alkylthiophene. UV-vis spectroscopic properties of the synthesized compounds are strongly dependent on the nature of the aryl group, the position of the solubilizing substituent and the length of the molecule, showing the highest bathochromic shift (λmax > 440 nm) for five-ring compounds with alkyl groups attached to Cα carbon in the terminal thienyl ring. An excellent linear correlation has been found for spectroscopically determined and theoretically calculated (TD-B3LYP/6- 31G*) excitation energies. With the exception of dipyridyl derivative, the calculated lowest unoccupied molecular orbital (LUMO) level of the investigated molecules changes within a narrow range (from -2.63 to -2.41 eV), in line with the electrochemical data, which show a reversible reduction process with the redox potential varying from -1.23 V to -1.33 V (vs. Fc/Fc+). The electrochemically determined positions of the LUMO levels are consistently lower by 0.9 to 1.2 eV with respect to the calculated ones. All molecules readily crystallize. Single crystal studies of 3,6-bis(2,2′-bithien-5-yl)-1,2,4,5- tetrazine show that it crystallizes in a P21/c space group whose structural arrangement is not very favorable to the charge carriers flow within the crystal. Powder diffraction studies of other derivatives have shown that their structural organization is sensitive to the position of the solubilizing substituent. In particular, the presence of alkyl groups attached to C α carbon in the terminal thienyl ring promotes the formation of a lamellar-type supramolecular organization.
Electrophilic cyanations using 1-cyanobenzotriazole: sp2 and sp carbanions
Hughes, Terry V.,Cava, Michael P.
, p. 313 - 315 (2007/10/03)
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