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21.
Lucia Veltri Roberta Amuso Marzia Petrilli Corrado Cuocci Maria A. Chiacchio Paola Vitale Bartolo Gabriele 《Molecules (Basel, Switzerland)》2021,26(8)
A straightforward approach to new polycyclic heterocycles, 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones, is presented. It is based on the ZnCl2-promoted deprotective 6-endo-dig heterocyclization of N-Boc-2-alkynylbenzimidazoles under mild conditions (CH2Cl2, 40 °C for 3 h). The zinc center plays a dual role, as it promotes Boc deprotection (with formation of the tert-butyl carbocation, which can be trapped by substrates bearing a nucleophilic group) and activates the triple bond toward intramolecular nucleophilic attack by the carbamate group. The structure of representative products has been confirmed by X-ray diffraction analysis. 相似文献
22.
Lucantonio Petrilli Alberto Flamini Nicola Poli 《Journal of inclusion phenomena and macrocyclic chemistry》1996,24(4):311-323
The metal(II) coordinating anion 2-(5-amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide (C11N7H
2
–
, L, max = 570 nm) has been incorporated by impregnation as the sodium salt in a membrane (0.1 mm thick) of crosslinked polyvinylformal (PVF) at a concentration 1.5 × 10–3 M. The L-doped PVF membrane, soaked in a concentrated aqueous solution of Cu2+ (0.1 M), changes colour from violet to blue on formation of the corresponding pure bis-pyrrolizinato complex CuL2 (max = 660 nm). The CuL2-doped PVF membrane reacts in the gas phase on exposure to species (X) that are copper-coordinating ligands stronger than L, generating the reverse colour change to violet. The remarkable stability towards water of CuL2/PVF is a promising indication for prospective use of ML2 complexes, incorporated in polymeric membranes, for the detection of (X) species in the atmosphere even in the presence of moisture, or directly in aqueous solutions.Abbreviations
average molecular weight;
- wt
weight
- min
minutes
- max
maximum
- M
molar
- c
concentration 相似文献
23.
E. L. Muñoz A. W. Carbonari L. A. Errico A. G. Bibiloni H. M. Petrilli M. Rentería 《Hyperfine Interactions》2007,178(1-3):37-43
The combination of hyperfine techniques and ab initio calculations has been shown to be a powerful tool to unravel structural and electronic characterizations of impurities in solids. A recent example has been the study of Cd-doped SnO, where ab initio calculations questioned previous TDPAC assignments of the electric-field gradient (EFG) in 111In-implanted Sn-O thin films. Here we present new TDPAC experiments at 111In-difused polycrystalline SnO. A reversible temperature dependence of the EFG was observed in the range 295–900 K. The TDPAC results were compared with theoretical calculations performed with the full-potential linearized augmented plane wave (FP-LAPW) method, in the framework of the density functional theory. Through the comparison with the theoretical results, we infer that different electronic surroundings around Cd impurities can coexist in the SnO sample. 相似文献