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211.
Prof. Dariush Ajami Giannoula Theodorakopoulos Ioannis D. Petsalakis Prof. Julius Rebek Jr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):17092-17096
Encapsulation complexes permit the observation of molecules under conditions of limited motion. Inside capsules, molecular encounters are prolonged, prearranged, and protected from the medium, in contrast to the short‐lived and random encounters that occur in bulk solution. Herein, the interaction of α‐, β‐, and γ‐picolines in a cylindrical capsule is described. Two picolines were taken up, and NMR spectra indicated dynamic combinations of various social isomers. The stabilities of the complexes are interpreted through computational methods. The shape of the space in the capsule allowed the alignment of molecules and revealed delicate, atom‐to‐atom interactions and attractive forces that elude observation in dilute solution. These weak forces were amplified in the isolated small space of the capsule. 相似文献
212.
Farahnaz Nourmohammadian Issa Yavari Dariush Ajami 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):443-451
Abstract Ab initio molecular orbital calculations at HF/6-31G*, HF/6-311+G**, and B3LYP/6-311+G** levels of theory for geometry optimization are reported for 1,4-dithiopyrrolo[3,4-c]pyrrole (DtPP, 1) and its twelve structural isomers (2–13). Compounds 1–3 include 2 C─CH and 2 NH─CS structural units. Structural isomers 4–7 include 2 C–CH units, together with 2 NH and 2 C–S groups. Isomers 8–13 possess 2 CH, 2 C, 2 NH, and 2 C─S fragments. According to these calculations, isomers 2, 4, and 8, are more stable than 1. 相似文献
213.
Rahim Hekmatshoar Sanaz Souri Mahshid Rahimifard Farnoosh Faridbod 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2827-2833
Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate(DMAD) by substituted phenols lead to vinyl triphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with a phenolate conjugate base to produce 4-carboxymethyl coumarins in fairly highly yields. 相似文献
214.
A combination of benzyltriethylammonium borohydride and chlorotrimethylsilane (1:1) in dichloromethane (0–25°C) has been found to be a convenient reagent system for the selective reduction of carboxylic acids to alcohols. 相似文献