Liu Guang-Ning, Zhang Xu, Wang Hong-Mei, Xu Hong, Wang Zi-Han, Meng Xiang-Long, Dong Ya-Nan, Zhao Ruo-Yu, Li Cuncheng
Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China.
Dalton Trans. 2017 Sep 26;46(37):12474-12486. doi: 10.1039/c7dt02152f.
Two types of in situ formed structure directing agents (SDAs) including aromatic triphenylphosphine (PPh)- and aliphatic piperazine (Hpp)-derivative cations were used to synthesize five new hybrid iodoargentates, namely (EtPPh)AgI (1, Et = ethyl), (n-PrPPh)AgI (2, n-Pr = n-propyl), (i-PrPPh)AgI (3, i-Pr = isopropyl), (Mepp)AgI (4, Me = methyl), and (Happ)(AgI)·2I·2HO (5, app = N-aminoethylpiperazine). A comparative study of the two types of SDAs on the structures, stabilities and properties of hybrid iodoargentates was performed in detail. Structurally, except for (EtPPh) and (n-PrPPh), which both directly form (AgI) anionic chains in 1 and 2, three SDAs generate hybrid iodoargentates different from each other with inorganic anions ranging from a 0-D (AgI) dimer to 1-D α-type (AgI) and (AgI) chains. With regard to the electronic structures, aromatic PPh-derivative cations make noticeable contributions to the bottom of the conduction bands, while aliphatic pp-derivative cations make nearly no contribution to the frontier orbitals, clearly indicating their different ways to adjust the band gaps. With regard to stability, the decomposition temperatures of 1-3 in the range of 324-349 °C are noticeably higher than the values of 217 and 225 °C for 4 and 5. Furthermore, 1-4 exhibit good water stabilities, which is ascribed to the alkylation reactions precluding the formation of strong hydrogen bonds between alkylated SDAs and extraneous HO molecules. Contrarily, the presence of typical hydrophilic [double bond, length as m-dash]NH, [triple bond, length as m-dash]NH and -NH groups on the protonated (Happ) cation makes 5 sensitive to water and a hydrolysis reaction occurs to generate a cubic AgI phase. Finally, 1-3 exhibit high photocatalytic efficiencies for the degradation of rhodamine B (RhB) dye in wastewater under visible light. All conclusions obtained here will help a lot in the synthesis of stable functional metal halide-based hybrids.
使用两种原位形成的结构导向剂（SDA），包括芳族三苯基膦（PPh）-和脂肪族哌嗪（Hpp）-衍生物阳离子，合成了五种新型杂化碘银酸盐，即（EtPPh）AgI（1，Et = 乙基）、（n-PrPPh）AgI（2，n-Pr = 正丙基）、（i-PrPPh）AgI（3，i-Pr = 异丙基）、（Mepp）AgI（4，Me = 甲基）和（Happ）（AgI）·2I·2H₂O（5，app = N-氨基乙基哌嗪）。详细研究了这两种类型的SDA对杂化碘银酸盐的结构、稳定性和性质的影响。在结构上，除了（EtPPh）⁺和（n-PrPPh）⁺在1和2中直接形成（AgI）⁻阴离子链外，三种SDA生成了彼此不同的杂化碘银酸盐，其无机阴离子范围从0维（AgI）二聚体到1维α型（AgI）⁻和（AgI）₄³⁻链。关于电子结构，芳族PPh-衍生物阳离子对导带底部有显著贡献，而脂肪族pp-衍生物阳离子对前沿轨道几乎没有贡献，清楚地表明了它们调节带隙的不同方式。关于稳定性，1-3在324-349°C范围内分解温度明显高于4和5的217和225°C。此外，1-4表现出良好的水稳定性，这归因于烷基化反应阻止了烷基化SDA与外来H₂O分子之间形成强氢键。相反，质子化（Happ）⁺阳离子上典型的亲水性[双键，长度为m破折号]NH、[三键，长度为m破折号]NH和-NH基团的存在使5对水敏感并发生水解反应生成立方AgI相。最后，1-3在可见光下对废水中罗丹明B（RhB）染料的降解表现出高光催化效率。这里获得的所有结论将对合成稳定的基于功能金属卤化物的杂化物有很大帮助。
