title: Heteroanionic Materials Based on Copper Clusters, Bisphosphonates, and Polyoxometalates: Magnetic Properties and Comparative Electrocatalytic NO(x) Reduction Studies.
abstract: Three compounds associating for the first time polyoxotungstates, bisphosphonates, and copper ions were structurally characterized. They consist in heteropolyanionic monodimensional materials where [Cu6(Ale)4(H2O)4](4-) (Ale = alendronate = [O3PC(O)(C3H6NH3)PO3](4-)) complexes alternate with polyoxometalate (POM) units. In Na12[{SiW9O34Cu3(Ale)(H2O)}{Cu6(Ale)4(H2O)4}]·50H2O (SiW9CuAle), the polyoxometalate core consists in a {SiW9Cu3} monomer capped by a pentacoordinated Ale ligand, while sandwich-type Keggin {(SbW9O33)2Cu3(H2O)(2.5)Cl(0.5)} and Dawson {(P2W15O56)2Cu4(H2O)2} complexes are found in Na8Li29[{(SbW9O33)2Cu3(H2O)(2.5)Cl(0.5)}2{Cu6(Ale)4(H2O)4}3]·163H2O (SbW9CuAle) and Na20[{(P2W15O56)2Cu4(H2O)2}{Cu6(Ale)4(H2O)4}]·50H2O (P2W15CuAle), respectively. A comparative magnetic study of the SiW9CuAle and SbW9CuAle compounds enabled full quantification of the Cu(II) superexchange interactions both for the POM and non-POM subunits, evidencing that, while the paramagnetic centers are anti-ferromagnetically coupled in the polyoxometalate units, both anti-ferromagnetic and ferromagnetic interactions coexist in the {Cu6(Ale)4(H2O)4} cluster. All the studied compounds present a good efficiency upon the reduction of HNO2 or NO2(-), the POM acting as a catalyst. However, it has been found that SbW9CuAle is inactive toward the reduction of nitrates, highlighting that both the {(SbW9O33)2Cu3} unit and the {Cu6(Ale)4(H2O)4} cluster do not act as electrocatalysts for this reaction. In contrast, SiW9CuAle and P2W15CuAle have shown a significant activity upon the reduction of NO3(-) and thus both at pH 1 and pH 5, evidencing that the chemical nature of the polyoxometalate is a crucial parameter even if it acts as precatalyst. Moreover, comparison of the activities of P2W15CuAle and [(P2W15O56)2Cu4(H2O)2](16-) evidenced that if the [Cu6(Ale)4(H2O)4](4-) cluster does not act as electrocatalyst, it acts as a cofactor, significantly enhancing the catalytic efficiency of the active POM.
authors: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, Université Paris-Saclay , 45 Avenue des Etats-Unis, 78035 Versailles cedex, France.
authors: Olivier
authors: O
authors: Oms
authors: Institut de Chimie, Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide, UMR CNRS 7177, Université de Strasbourg , 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg cedex, France.
authors: Shu
authors: S
authors: Yang
authors: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, Université Paris-Saclay , 45 Avenue des Etats-Unis, 78035 Versailles cedex, France.
authors: William
authors: W
authors: Salomon
authors: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, Université Paris-Saclay , 45 Avenue des Etats-Unis, 78035 Versailles cedex, France.
authors: Jérôme
authors: J
authors: Marrot
authors: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, Université Paris-Saclay , 45 Avenue des Etats-Unis, 78035 Versailles cedex, France.
authors: Anne
authors: A
authors: Dolbecq
authors: Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182, CNRS, Univ. Paris-Sud, Université Paris-Saclay , 91405 Orsay cedex, France.
authors: Eric
authors: E
authors: Rivière
authors: Institut de Chimie, Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide, UMR CNRS 7177, Université de Strasbourg , 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg cedex, France.
authors: Antoine
authors: A
authors: Bonnefont
authors: Institut de Chimie, Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide, UMR CNRS 7177, Université de Strasbourg , 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg cedex, France.
authors: Laurent
authors: L
authors: Ruhlmann
authors: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, Université Paris-Saclay , 45 Avenue des Etats-Unis, 78035 Versailles cedex, France.
authors: Pierre
authors: P
authors: Mialane