Non-covalent interactions in hexanuclear polyoxidometalates [VIV6B20O50H8]8−. An experimental and theoretical approach. (1st January 2022)

• Record Type: Journal Article
• Authors: Muñoz-Becerra, Karina; Wrighton-Araneda, Kerry; Le Fur, Eric; Saillard, Jean-Yves; Kahlal, Samia; Cador, Olivier; Paredes-García, Verónica; Venegas-Yazigi, Diego
• Is Part Of: Polyhedron. Volume 211(2022)
• Publication Date: 2022-01-01
• Subjects: Polyoxidometalates -- Non-covalent interactions -- Magnetic properties -- Spectroscopic properties -- DFT calculations; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2021.115553
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: The magnetic and electronic properties of crystalline packing of polyoxometalates of the [V IV 6 B20 O50 H8 ] 8− family were studied experimentally and theoretically. The magnetic V IV -V IV coupling is strongly dependent on the non-covalent interactions between K cations and polyanions, while the UV–Vis properties are dominated by MMCT and d - d transitions within the {V6 IV O18 } 12− chromophore. Abstract: A complete study of the optical and magnetic properties of three new {V6 -type} polyoxidometalates (NH3 CH2 CH2 CH2 NH3 )4 {V6 B20 O50 H8 }·4H2 O 1, K2 (NH3 CH2 CH2 NH3 )2.5 (NH3 CH2 CH2 NH2 ){V6 B20 O50 H8 }·2H2 O 2, and K2 (NH3 CH2 CH2 CH2 NH3 )2 (H3 O)2 {V6 B20 O50 H8 }·8H2 O 3 is presented. Using TD-DFT calculations, the assignment of the experimental UV–Visible spectra was established with four absorption bands: a higher in energy assigned to metal-to-metal charge transfer and the remaining associated principally to d-d transitions, demonstrating that the {V6 IV O18 } 12− ring is the principal chromophore for these systems and that the surrounding packing does not have an influence on it. On the other hand, the differences observed in the magnetic properties are caused by the influence of the non-covalent interactions between the potassium ions with some oxygen atoms of the V IV coordination spheres, thus modifying the V IV -V IV exchange coupling. This effect was demonstrated using a simplified binuclear DFT model that predicts a higher V IV -V IV antiferromagnetic coupling when the K cations become closer to the oxygen bridge atoms that link the V IV centres of the {V6 IV O18 } 12− ring.