Synthesis and photochromic properties of spiro[naphthopyran-7′H-benzocyclohepta-5′,8′-dienes]
摘要:
A series of spironaphthopyrans has been synthesised by the acid-catalysed condensation between either a substituted 1-naphthol or 2-naphthol and the propargylic alcohol derived from the addition of lithium trimethylsilylacetylide to a 7H-benzocycloheptan-7-one with subsequent in situ silyl group removal. The photochromism of the novel spironaphthopyrans was characterised by a bathochromically shifted lambda(max) coupled with a relatively quick initial fade of the photogenerated species relative to the comparable diphenyl substituted model compounds. After initial fading a relatively intense residual colour persisted for the spironaphthopyrans. (C) 2012 Elsevier Ltd. All rights reserved.
The properties of 1-hydroxy-4,5-arene-fused tropyliums were assessed based on experimental and theoretical investigations. An X-ray crystallographic analysis revealed a decrease of bond alternation in the seven-membered ring of 1-hydroxy-4,5-benzotropylium derivatives compared with that of the parent 4,5-benzotropones, which is indicative of an increase in aromaticity upon protonation. NICS and AICD
基于实验和理论研究评估了 1-羟基-4,5-芳烃稠合的 tropyliums 的性质。X 射线晶体学分析显示,与母体 4,5-苯并托酮相比,1-羟基-4,5-苯并托鎓衍生物的七元环中的键交替减少,这表明芳香性增加质子化。NICS 和 AICD 计算也支持 1-羟基-4,5-芳烃稠合的 tropylium 的芳香性增加。还测定了一系列 1-羟基-4,5-芳烃稠合的托鎓衍生物的 p K a值。
Synthesis of 4,5-Benzotropone π Complexes of Iron, Rhodium, and Iridium and Their Potential Use in Catalytic Borrowing-Hydrogen Reactions
The syntheses of rhodium, iridium, and iron π complexes bearing 4,5-benzotropone ligands are reported. X-ray crystallographic analyses revealed that a tropone core coordinates to a metal center in a η4 manner with a tub-form geometry. Some of the benzotropone π complexes exhibited catalyticactivity for N-alkylation of aniline by borrowing hydrogen.