Routh Kousik, Pradeep Chullikkattil P
School of Chemical Sciences, Indian Institute of Technology Mandi, Kamand 175005, Himachal Pradesh, India.
Inorg Chem. 2023 Aug 28;62(34):13775-13792. doi: 10.1021/acs.inorgchem.3c01470. Epub 2023 Aug 14.
Multifunctional materials based on polyoxovanadates (POVs) have rarely been reported. Herein, we used aryl sulfonium counterions (ASCIs) bearing a salicylaldehyde-type functionality to tune the properties of decavanadate ([VO])-based hybrids for their application in photochromism and heterogeneous oxidative desulfurization (ODS) catalysis. The counterions FHPDS ((3-formyl-4-hydroxyphenyl)dimethylsulfonium), DFHPDS ((3,5-diformyl-4-hydroxyphenyl)dimethylsulfonium), and EFPDS ((4-ethoxy-3-formylphenyl)dimethylsulfonium) were clubbed with the decavanadate cluster to generate the hybrids (FHPDS)HVO (), (DFHPDS)HVO (), and (EFPDS)HVO (). The photochromic properties of these hybrids were tested under 365 nm irradiation, which showed a color change from yellow to green. Different hybrids exhibited different photocoloration half-life () values in the range of 0.77-28.38 min, suggesting the dependence of the photocoloration properties upon functional groups on the counterions. The hybrid , having a 2,6-diformyl phenol moiety on the ASCI, exhibited an impressive of 0.77 min. UP to 70% reversibility of photocoloration was achieved for the best photochromic hybrid in 48 h at 70 °C under an oxygen atmosphere. Theoretical and experimental data suggested that some of these aryl sulfonium POVs follow a different e-h stabilization mechanism than traditional sulfonium POM hybrids. Further, the salicylaldehyde-type ASCIs control the solubility of the decavanadate hybrids, which enables their application as heterogeneous catalysts for the selective oxidation of various sulfides. The nature of the substituents on the ASCIs also affected their catalytic activities; the counterion that facilitates the reversible V/V switching enhances the catalytic ODS efficiency of the hybrids. Using as the catalyst, up to 99% conversion and 96% selectivity toward sulfones were achieved in dibenzothiophene (DBT) oxidation. The present study suggests a new promising approach for controlling POVs' photoresponsive and catalytic properties by using ASCIs bearing salicylaldehyde-type functional moieties.
基于多钒酸盐（POV）的多功能材料鲜有报道。在此，我们使用带有水杨醛型官能团的芳基锍抗衡离子（ASCI）来调节基于十钒酸盐（[VO]）的杂化物的性质，以用于光致变色和多相氧化脱硫（ODS）催化。抗衡离子FHPDS（(3 - 甲酰基 - 4 - 羟基苯基)二甲基锍）、DFHPDS（(3,5 - 二甲基 - 4 - 羟基苯基)二甲基锍）和EFPDS（(4 - 乙氧基 - 3 - 甲酰基苯基)二甲基锍）与十钒酸盐簇结合生成杂化物（FHPDS）HVO （）、（DFHPDS）HVO （）和（EFPDS）HVO （）。这些杂化物的光致变色性质在365 nm光照下进行测试，结果显示颜色从黄色变为绿色。不同的杂化物在0.77 - 28.38分钟范围内表现出不同的光致变色半衰期（）值，这表明光致变色性质取决于抗衡离子上的官能团。在ASCI上带有2,6 - 二甲基苯酚部分的杂化物表现出令人印象深刻的0.77分钟的半衰期。在氧气气氛下，70℃时，最佳光致变色杂化物在48小时内实现了高达70%的光致变色可逆性。理论和实验数据表明，这些芳基锍POV中的一些遵循与传统锍多金属氧酸盐杂化物不同的电子 - 空穴稳定机制。此外，水杨醛型ASCI控制十钒酸盐杂化物的溶解度，这使其能够作为多相催化剂用于各种硫化物的选择性氧化。ASCI上取代基的性质也影响它们的催化活性；促进可逆V/V转换的抗衡离子提高了杂化物的催化ODS效率。使用作为催化剂，在二苯并噻吩（DBT）氧化中实现了高达99%的转化率和96%的砜选择性。本研究提出了一种通过使用带有水杨醛型官能部分的ASCI来控制POV的光响应和催化性质的新的有前景的方法。
