摘要详情
116 / 2023-10-09 21:31:04
Heterogeneous Visible-light-driven P-centered Radical Formation Using an Molecular Mo Oxide as Photosensitizer
polyoxometalates, heterogeneous catalysis, cross-dehydrogenative coupling, photocatalytic, green chemistry
摘要录用
In recent decades, with the rapid development of free radical chemistry, the use of metal salts, peroxides, photocatalysts, etc., through single electron transfer (SET) or hydrogen atom transfer (HAT), have been demonstrated effective protocols to generate X-P bonds with P-centered free radicals. Therefore, in the past few years, there has been a new understanding of the use of P-central radicals to construct crucial organophosphorus compounds. In particular, significant progress has been made in the P-centered free radical phosphorylation of organic compounds mediated by transition metals or excessive oxidants.[1-4]
With the increasing importance of the concept of green chemistry, chemical workers have been paying attention to the development of synthetic methods with high atomic economy and step economy, as well as greener reaction conditions. To achieve these goals, photocatalytic reaction system, and electrochemical reaction, have been successfully applied to the formation of X-P bonds. In the field of photo-induced P-centered radical generation, a variety of photocatalyst have been established to break the H-P bond in the P(O)H compounds.[5] The photosensitizer mainly included transition metal complexes and organic catalysts. Although these catalytic systems have significant advantages, their further practical applications are greatly limited by drawbacks such as high cost of precious metals, poor stability and durability of organic compounds.
Polyoxometalates (POMs) are metal oxide clusters with unique photo-induced charge-transfer properties and redox properties. Compared to organic or organometallic-based based homogeneous photocatalysts, they have higher thermal and oxidative stability. Reported according to literature, only three types of POM photocatalysts, viz. Dawson-type ([X2M18O62]n-), Keggin-type ([XM12O40]n-), and decatungstate ([W10O32]4-),[6-12] were found to be photoactive in organic functional group transformations. Considering that molybdenum and tungsten are both VIB group elements with similar properties, and molybdenum-based polyoxometalates can absorb UV light due to the large HOMO-LUMO gap energy, we therefore envisioned that if polyoxomolybdates could be employed as a photocatalyst to facilitate the oxidative dehydrogenative coupling reactions of R–H/R’–H with oxygen as the oxidant after being excited by visible light.
We herein demonstrated that P-centered radical could be generated through a Lindquist-type polyoxomolybdate, [N(C4H9)4]2[Mo6O19], after being excited by visible-light irradiation. This catalyst can be readily synthesized from cheap and commonly available (NH4)6Mo7O24·4H2O and [N(C4H9)4]Br in one pot in aqueous solution.[13] Moreover, the P-centered radical can generate even using water as the solvent, or with the irradiation of sunlight. These features made this P-centered radical formation pathway extremely green, sustainable and practical. It also provided a platform for the further construction of X-P bonds.
With the increasing importance of the concept of green chemistry, chemical workers have been paying attention to the development of synthetic methods with high atomic economy and step economy, as well as greener reaction conditions. To achieve these goals, photocatalytic reaction system, and electrochemical reaction, have been successfully applied to the formation of X-P bonds. In the field of photo-induced P-centered radical generation, a variety of photocatalyst have been established to break the H-P bond in the P(O)H compounds.[5] The photosensitizer mainly included transition metal complexes and organic catalysts. Although these catalytic systems have significant advantages, their further practical applications are greatly limited by drawbacks such as high cost of precious metals, poor stability and durability of organic compounds.
Polyoxometalates (POMs) are metal oxide clusters with unique photo-induced charge-transfer properties and redox properties. Compared to organic or organometallic-based based homogeneous photocatalysts, they have higher thermal and oxidative stability. Reported according to literature, only three types of POM photocatalysts, viz. Dawson-type ([X2M18O62]n-), Keggin-type ([XM12O40]n-), and decatungstate ([W10O32]4-),[6-12] were found to be photoactive in organic functional group transformations. Considering that molybdenum and tungsten are both VIB group elements with similar properties, and molybdenum-based polyoxometalates can absorb UV light due to the large HOMO-LUMO gap energy, we therefore envisioned that if polyoxomolybdates could be employed as a photocatalyst to facilitate the oxidative dehydrogenative coupling reactions of R–H/R’–H with oxygen as the oxidant after being excited by visible light.
We herein demonstrated that P-centered radical could be generated through a Lindquist-type polyoxomolybdate, [N(C4H9)4]2[Mo6O19], after being excited by visible-light irradiation. This catalyst can be readily synthesized from cheap and commonly available (NH4)6Mo7O24·4H2O and [N(C4H9)4]Br in one pot in aqueous solution.[13] Moreover, the P-centered radical can generate even using water as the solvent, or with the irradiation of sunlight. These features made this P-centered radical formation pathway extremely green, sustainable and practical. It also provided a platform for the further construction of X-P bonds.
重要日期
-
会议日期
11月12日
2023
至11月16日
2023
-
10月24日 2023
初稿截稿日期
-
11月16日 2023
注册截止日期
主办单位
Ningbo University
