(VIVO)2MII5] (M = Ni, Co) Anderson wheels.

Hector W L Fraser,Emily H Payne,Arup Sarkar,Euan K Brechin,Gopalan Rajaraman,Gary S Nichol,Dmitri Mitcov,Stergios Piligkos,Lucinda R B Wilson

doi:10.1039/d1dt01710a

Abstract

Heterometallic Anderson wheels of formula [(VIVO)2MII5(hmp)10Cl2](ClO4)2·2MeOH (M = Ni, 1; Co, 2) have been synthesised from the solvothermal reaction of M(ClO4)2·6H2O and VCl3 with hmpH (2-(hydroxymethyl)pyridine). The metallic skeleton describes a centred hexagon, with the two vanadyl ions sitting on opposing sides of the outer ring. Magnetic susceptibility and magnetisation measurements indicate the presence of both ferromagnetic and antiferromagnetic exchange interactions. Theoretical calculations based on density functional methods reproduce both the sign and strength of the exchange interactions found experimentally, and rationalise the parameters extracted.

Highlights

Alongside its prominent role in polyoxometalate chemistry,1 vanadium has had significant impact in the field of moleculebased magnetism
The recent success we have had in employing the ligand 2-(hydroxymethyl)pyridine in the construction of heterometallic Anderson wheels of general formula [MI2IIMI5I(hmp)12]4+,11 hinted that this might be a viable route to isolating similar MIV–MII cages
Paper highlights the apparent stability of the Anderson wheel structure, and the modular nature of the molecule whereby different metals in different oxidation states can be combined with the same ligand sets to afford analogous species

Summary

Introduction

Alongside its prominent role in polyoxometalate chemistry, vanadium has had significant impact in the field of moleculebased magnetism. Restricting the search to complexes of any nuclearity containing the VIV– O–MII (M = Ni, Co) moiety, and excluding polyoxometalates, surprisingly affords only two different structure types: [(VO)M] dimers, and a single [(VO)6M] wheel.. Restricting the search to complexes of any nuclearity containing the VIV– O–MII (M = Ni, Co) moiety, and excluding polyoxometalates, surprisingly affords only two different structure types: [(VO)M] dimers, and a single [(VO)6M] wheel.10 The latter complex has the formula [MVI6VO6{(OCH2CH2)2N(CH2CH2OH)}6]X (X = halide) in which the six vanadyl moieties form a wheel that ‘encapsulates’ a variety of s- and 3d metal ions (M).. The recent success we have had in employing the ligand 2-(hydroxymethyl)pyridine (hmpH) in the construction of heterometallic Anderson wheels of general formula [MI2IIMI5I(hmp)12]4+ (where MIII = Cr, Al and MII = Mn, Fe, Co, Ni, Cu, Zn), hinted that this might be a viable route to isolating similar MIV–MII cages

Experimental procedures

Results and discussion

Complex Method

Conclusions