Issue 31, 2018

Bicapped Keggin polyoxomolybdates: discrete species and experimental and theoretical investigations on the electronic delocalization in a chain compound

Abstract

Three monomeric polyoxometalates [M(C10H8N2)3][α-PMoVI9MoV3O40Zn2(C10H8N2)2]·2H2O (M-PMo12Zn2, M = Fe, Co, Ru) with {Zn(bpy)2}2+ units capped on reduced α-Keggin polyanions and [M(bpy)3]2+ counter-ions were synthesized under hydrothermal conditions. The 1D polymer [N(C4H9)4][Ru(C10H8N2)3][α-PMoVI8MoV6O43] (Ru-PMo14) was prepared by a similar strategy, in the absence of 2,2′-bpy ligands. In this chain capped reduced Keggin anions are linked via Mo–O–Mo bridges and are surrounded by both tetrabutylammonium cations and [Ru(bpy)3]2+ counter-ions. The compounds were characterized in the solid state by single crystal and powder X-ray diffraction and IR spectroscopy and in solution by 31P NMR spectroscopy. 31P diffusion ordered NMR spectroscopy (DOSY) indicates that the diffusion coefficient of the dissolved species of Ru-PMo14 corresponds to a dimeric structure. Magnetic susceptibility measurements performed on Ru-PMo14 show the existence of antiferromagnetic interactions between the d1 electrons of the six MoV centers, with a singlet spin ground state. However, attempts to fit the data in the 2–300 K temperature range with Heisenberg Hamiltonians adapted for 0 or 1D systems suggest that these electrons are delocalized. Density Functional Theory (DFT) and Wave Function Theory (WFT) calculations indicate a migration of the electrons of the capping MoV centers into the PMo12 units at high temperature, allowing the rationalization of the experimental observations.

Graphical abstract: Bicapped Keggin polyoxomolybdates: discrete species and experimental and theoretical investigations on the electronic delocalization in a chain compound

Supplementary files

Article information

Article type
Paper
Submitted
04 апр. 2018
Accepted
04 мај 2018
First published
24 мај 2018

Dalton Trans., 2018,47, 10636-10645

Bicapped Keggin polyoxomolybdates: discrete species and experimental and theoretical investigations on the electronic delocalization in a chain compound

W. Salomon, E. Rivière, X. López, N. Suaud, P. Mialane, M. Haouas, A. Saad, J. Marrot and A. Dolbecq, Dalton Trans., 2018, 47, 10636 DOI: 10.1039/C8DT01313F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements