Assembly of trimeric polyoxovanadate aggregates based on [MnV _(13)O_(38)]~(7-) building blocks and lanthanide cations

摘要

Three trimeric polyoxovanadate based on 1:13 anions [MnV_(13)O _(38)]~(7-) with lanthanide cations Ln~(3+) (Ln = La, Ce and Nd) and pyridine-3-carboxylic acid: HK_3{[Ln(H_2O) _4]_6[MnV_(13)O_(38)]_3(SO _4)_2}·3(C_6H_6NO _2)·nH_2O (Ln = La 1, Nd 3; n = 33 for 1, 20 for 3), H_(2.5)K_(1.5){[Ce(H_2O)_4]_ 6[MnV_(13)O_(38)]_3(SO_4) _2}·3(C_6H_6NO_2)·20. 5H_2O (2) (C_6H_5NO_2 = pyridine-3-carboxylic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV spectroscopy, TG analysis, XPRD, electrochemical analyses, magnetism and single-crystal X-ray diffraction. Compounds 1-3 are isostructural and crystallized in the hexagonal system, space group P6 3/m. Compounds 1-3 contain an unusual trimeric polyoxoanion [{Ln _2MnV_(13)O_(38)}_3(SO_4)_ 2]~(7-), representing the first polyoxovanadate-based trimeric aggregate with rare earth ions. The electrochemical and electrocatalytic properties of the compounds have been investigated. Magnetic studies indicate that antiferromagnetic interactions exist in the compounds.