RESUMEN
We designed and synthesized a novel di(benz[f]indenone)-fused tetraazaanthracene derivative and isolated its two isomers, 1a and 1s, having anti and syn configurations, respectively. Their structure and that of the condensation reaction intermediates, anti-2a and syn-2s, were fully characterized using one- and two-dimensional nuclear magnetic resonance spectroscopy and single-crystal X-ray diffraction. The optical and electronic properties of 1a and 1s were investigated using ultraviolet-visible absorption and fluorescence spectroscopies, cyclic voltammetry, and time-dependent density functional theory calculations. The presence of the carbonyl and ethynyltris(isopropyl)silane groups endows the di(benzoindenone)-fused azaacene derivatives with a strong electron accepting character. With an electron affinity of approximately -3.7 eV, the two isomers represent attractive electron-deficient molecular systems for the generation of n-channel semiconducting materials. Organic field effect transistors of 1a and 1s showed electron transport, and organic solar cells gave a proof of concept of the potential of the two compounds as electron acceptor materials when they are paired with an electron donor polymer.
RESUMEN
A convenient and versatile procedure for the straightforward synthesis of substituted fluorenones as valuable scaffolds is described under rhodium catalysis. The present [2 + 2 + 2] cycloaddition reaction of diynes with 3-acetoxy or-3-alkoxyindenones as surrogates of the highly reactive benzocyclopentynone 2π partner allows the preparation of various fluorenone-type derivatives in good yields and provides an additional and tunable process for the generation of more challenging molecules with application in pharmaceutical, polymer, and material sciences.
RESUMEN
A regioselective functionalization of the pyrazolo[1,5- a]pyridine scaffold using Mg- and Zn-TMP bases (TMP = 2,2,6,6-tetramethylpiperidyl) in the presence or absence of BF3·OEt2 is described. Also, various functionalized pyrazolo[1,5- a]pyridines bearing an ester function (and an NHBoc or ethyl group) are magnesiated and functionalized, leading to polysubstituted heterocycles. Additionally, a sulfoxide directed ortho-metalation, followed by the transition-metal-free amination of a pyrazolo[1,5- a]pyridine sulfoxide, using a magnesium amide, is reported.