Accessing (Multi)Fluorinated Piperidines Using Heterogeneous Hydrogenation
作者:Tobias Wagener、Arne Heusler、Zackaria Nairoukh、Klaus Bergander、Constantin G. Daniliuc、Frank Glorius
DOI:10.1021/acscatal.0c03278
日期:2020.10.16
Fluorinated piperidines are desirable motifs for pharmaceutical and agrochemical research. Nevertheless, general synthetic access remains out of reach. Herein, we describe a simple and robust cis-selective hydrogenation of abundant and cheap fluoropyridines to yield a broad scope of (multi)fluorinated piperidines. This protocol enables the chemoselective reduction of fluoropyridines while tolerating
and N^O = pyridinecarboxylate and its derivatives) were synthesized and evaluated to identify the highest occupied molecular orbital (HOMO) energylevel (EHOMO) for efficient dye regeneration in dye-sensitizedsolarcells. EHOMO of these complexes was systematically tuned by changing the electron-donating ability of the C^N and N^O ligands. For complexes with an EHOMO in the potential range more negative
合成了[Ru(tctpy)(C ^ N)NCS类型和[Ru(tctpy)(N ^ O)NCS]类型的30种钌配合物(C ^ N =环金属配体,N ^ O =吡啶羧酸酯及其衍生物)并进行了评估,以确定在染料敏化太阳能电池中有效进行染料再生的最高占据分子轨道(HOMO)能级(E HOMO)。通过改变C ^ N和N ^ O配体的给电子能力,系统地调节了这些配合物的E HOMO。用于与络合物Ë HOMO在电位范围内时小于0.5V更负相对于饱和甘汞电极(SCE),与正移位增加入射光子-电流转换效率(IPCE)Ë HOMO但不能超过70%,这表明快速的染料再生是困难的。在另一方面,高IPCE上70%以上,用于与复合物经常观察Ë HOMO比0.5伏更积极与SCE。由此可以得出结论:有近0.5伏有效的电子转移的阈值相对于SCE(Δ G ^ 2为系列这些敏化剂的≈0.3电子伏特)。