Synthesis And Performance Of Functional Materials Based On Aryl Substituted Oxazole

Oxazoles are one of the most important heterocyclic compounds, which ubiquitously exist in natural and non-natural products. It has been proved that the derivatives of oxazole possessed excellent biological activities.Besides, oxazole derivatives also have a place in functional materials. The extensive application of oxazoles and its derivatives have driven an ever increasing number of scientists into this field. There are several ways to construct oxazole framework, including direct cross-coupling arylation, cyclization of acyclic precursors and oxidation of oxazolines. It is known to all that extra oxidants or heavy metals were necessary to promote the reactions. The reason why it is worthy to synthesize oxazoles with an effective means is that tedious synthetic procedures and purification are obstacles of the application of oxazoles. To expand the application of oxazole, we employed 2-pyridyl oxazole as sensor for the detection of metal ions.Moreover, we also have done research on the performance of functional materials in organic electroluminescence devices (OLED) based on aryl substituted oxazoles. This paper will be divided into several parts as following:Firstly (Part 2), a convenient method has been established for the chemoselective synthesis of polyarylated oxazoles from aromatic aldehydes and 2-cyano heteroarenes. The protocol presents a novel one-pot methodology for the synthesis of oxazole derivatives without any metal catalysts or extra oxidants. Photophysical test showed that the polyarylated oxazoles may serve as potential fluorescent materials with blue light-emitting properties.Secondly (Part 3), a highly sensitive fluorescent chemosensor for rhodium based on 2-pyridyl oxazoles was discovered. To the best of our knowledge, this is the first organic fluorescentchemosensor which can detect the existence of rhodium. The degree of fluorescence quenching reached up to 99% in several minutes under acidic conditions with high selectivity and high sensitivity.Substituted 2-pyridyl imidazoles were employed as selective optical chemosensors for sensing mercury or cobalt by changing the substituents. This newly designed sensing system exhibited fluorescence turn-off behavior toward Hg(II) and Co(II) in the presence of other competitive metal ions within several seconds, respectively.Finally (Part 4), we introduced the diphenyl paraoxonase into 2-pyridyl oxazoles, furnishing two brand new ETMs. The DSC and TGA experiments showed that the glass transition temperature and thermal stability became better because of the introduction of diphenyl paraoxonase. What’s more, thanks to the nonexpansion of conjugation system, triplet energy level stay unchanged, which is a guarantee for the good performance of ETM.A novel electron transporting material (ETM) was synthesized for OLED based on the core of 2-pyridyl oxazole. We introduce the pyridine into the skeleton by Suzuki coupling reaction, bringing about a new ETM. These compounds possessed high glass transition temperature and good thermal stability. Some other results suggested that these compounds’ electron transporting rate were close to the rate of CBP.