Li Dapeng, Zhang Peng, Ge Suxiang, Sun Guofu, He Qin, Fa Wenjun, Li Yun, Ma Juntao
Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, College of Chemical and Materials Engineering, Xuchang University Henan 461000 P. R. China
School of Civil Engineering and Communication, North China University of Water Resources and Electric Power Henan 450011 P. R. China.
RSC Adv. 2021 Sep 22;11(50):31226-31234. doi: 10.1039/d1ra04064b. eCollection 2021 Sep 21.
Exploring the environmentally friendly and low-cost synthesis strategies of phthalocyanine (Pc) crystals in just one step is an absolute challenge. The solvothermal synthesis of phthalocyanine crystals shows the advantages of high-quality crystalline products, facile reaction and purification, and low cost. Nevertheless, only a few metal phthalocyanine crystals have been successfully synthesized solvothermal reactions. In this study, we found that the crystalline β metal-free phthalocyanine needles could be directly prepared the tetrapolymerization of phthalodinitrile catalyzed by DBU in solvothermal reactions. Similar to the preparation of β-phthalocyanine crystals, the α metal-free phthalocyanine crystals with the specific multiply-laminated structures can be obtained through solvothermal reactions assisted by DBN. SEM characterization showed that the individual β metal-free phthalocyanine has a well-defined quadrangular shape with smooth faces. However, the α metal-free phthalocyanine exhibits a distinctive undulating surface morphology. Both phthalocyanines showed satisfactory thermal stability (from room temperature to about 300 °C), excellent resistance to acid/alkali solution, and fast photoelectric response properties (order of magnitude of response time, 10 s) as tested by TG-DSC and TPV, respectively. It is noted that ethanol was used as the reaction medium and the resulting phthalocyanine crystals can be facilely purified using hot ethanol to dissolve the impurities adsorbed on the surfaces of phthalocyanine crystals. Compared to the traditional methods, no re-crystallization operation was carried out for our method. To the best of our knowledge, this is the first report on the solvothermal synthesis of metal-free phthalocyanine crystals with controllable crystal form adjusted by DBU/DBN in one step.
一步探索酞菁（Pc）晶体的环保、低成本合成策略是一项绝对的挑战。酞菁晶体的溶剂热合成显示出高质量晶体产物、反应和纯化简便以及成本低的优点。然而，通过溶剂热反应成功合成的金属酞菁晶体只有少数几种。在本研究中，我们发现，在溶剂热反应中，由DBU催化邻苯二甲腈的四聚反应可直接制备出结晶性的β型无金属酞菁针状物。与β-酞菁晶体的制备类似，通过DBN辅助的溶剂热反应可获得具有特定多层结构的α型无金属酞菁晶体。扫描电子显微镜表征显示，单个β型无金属酞菁具有轮廓分明的四边形形状，表面光滑。然而，α型无金属酞菁呈现出独特的起伏表面形态。通过TG-DSC和TPV测试，两种酞菁均表现出令人满意的热稳定性（从室温到约300℃）、优异的耐酸碱溶液性以及快速的光电响应特性（响应时间量级为10 s）。值得注意的是，使用乙醇作为反应介质，所得的酞菁晶体可通过热乙醇轻松纯化，以溶解吸附在酞菁晶体表面的杂质。与传统方法相比，我们的方法无需进行重结晶操作。据我们所知，这是首次关于通过DBU/DBN一步调节晶型来溶剂热合成无金属酞菁晶体的报道。
