Easy Ligand Activation in the Coordination Sphere of Ru inside the [PW11O39]7– Backbone

Abstract

Irradiation of the Keggin-type [PW11O39{Ru(NO)}]4− (Ru-NO) polyoxometalate in CH3CN results in rapid NO ligand elimination with the formation of [PW11O39{RuIII(CH3CN)}]4− (Ru-CH3CN). This complex offers an easy entry into the Ru-based chemistry of the {PW11Ru} complex. Attempts to substitute N3− for CH3CN in the presence of an NaN3 excess lead a variety of products: (i) [PW11O39{RuIII(N3)}]4− (Ru-N3); (ii) [PW11O39{RuIII(N4HC-CH3)}]4− (Ru-Tz) as a click-reaction product; and (iii) [PW11O39{RuII(N2)}]5− (Ru-N2). UV-VIS, CV, and HR-ESI-MS techniques were used for the reaction monitoring and characterization of the products.

Binuclear Ru(III)-Containing Polyoxometalate with Efficient Photocatalytic Activity for Oxidative Coupling of Amines to Imines

“…31,78−81 In compound 1, the transition metal Ru site contains multiple d-electrons, allowing itself to exhibit good redox and catalytic properties. 27,82 According to the literature and experimental results, a possible reaction mechanism is proposed (Scheme 1). 77,83−89 First, in order to explore the electron transfer within Ru-POM under visible light, a solution containing 4-methoxybenzylamine (electron donor), acetoni- trile, and 1 was irradiated with visible light (λ > 400 nm) under an argon atmosphere, and the color of the solution changed from reddish brown to dark purple (Figure S9).…”

“…As a metal–oxygen cluster, POMs have a strong redox capacity and a homogeneous charge distribution, allowing for multiple electron transfer processes . Under light irradiation, the intramolecular charge is transferred from oxygen to metal to form a highly reactive excited POMs enabling the oxygen photolysis in multiple use cases, e.g., water oxidation, CO 2 reduction, pollutant degradation, and organic reactions. ,− In compound 1 , the transition metal Ru site contains multiple d-electrons, allowing itself to exhibit good redox and catalytic properties. , According to the literature and experimental results, a possible reaction mechanism is proposed (Scheme ). ,− First, in order to explore the electron transfer within Ru-POM under visible light, a solution containing 4-methoxybenzylamine (electron donor), acetonitrile, and 1 was irradiated with visible light (λ > 400 nm) under an argon atmosphere, and the color of the solution changed from reddish brown to dark purple (Figure S9).…”

Bioorthogonal chemistry of polyoxometalates – challenges and prospects

“…Metal centers are capable of activating organic molecules, thereby leading to the functionalization of POM. This concept was demonstrated by Sokolov et al 179 Keggin-type polyoxotungstate modified with a Ru center [PW 11 O 39 {Ru III (N 3 )}] 4− was functionalized with a tetrazolyl group by activating acetonitrile and azide ligands in the ruthenium coordination sphere. Reported reaction conditions included high temperatures and organic solvents; the reaction is not selective.…”

Bioorthogonal Chemistry of Polyoxometalates – Challenges and Prospects

“…Metal centers are capable of activating organic molecules, thereby leading to the functionalization of POM. This concept was demonstrated by Sokolov et al 153 Keggin-type polyoxotungstate modified with a Ru center [PW11O39{Ru III (N3)}] 4− are functionalized with a tetrazolyl group by activating acetonitrile and azide ligands in the ruthenium coordination sphere. Reported reaction conditions include high temperatures and organic solvents, and the reaction is not selective.…”