Tunable Three-Dimensional Magnetic Coordination Polymers

Joseph M Zadrozny

doi:10.21061/jumr.v2i0.0606

Abstract

Four chlorinated phenyltricyanoethylenes were synthesized and reacted with vanadium hexacarbonyl to form ferrimagnetic coordination polymers.Species chlorinated at the 2, 3, or 4 position of the ring as well as a dichlorinated analogue with substitution at both the 2 and 6 positions were examined.The magnetic ordering temperatures of the polymers were reproducible and ranged from 140 to 288 K. All compounds displayed soft ferrimagnetic behavior, and their structure-property relationships are discussed.

Highlights

In 1991, Manriquez and coworkers reported the discovery of the first room temperature molecule-based magnet, prepared from the reaction of vanadium hexacarbonyl and tetracyano ethylene (TCNE).[1]
Replacing V2+ with later transition metal ions such as Mn2+ or Fe2+ may overcome this limitation, such substituted compounds have been found to be non-magnetic at room temperature.[3]
Vanadium hexacarbonyl was synthe sized following procedures outlined in the literature.[6]

Summary

Introduction

In 1991, Manriquez and coworkers reported the discovery of the first room temperature molecule-based magnet, prepared from the reaction of vanadium hexacarbonyl and tetracyano ethylene (TCNE).[1]. The remaining (three) d-electrons on the cation give rise to lo cal moments which do not completely cancel each other out, resulting in a net magnetic moment Magnets created in this manner are of technological importance because their magnetic properties can be tuned by varying either of the two starting materials (i.e. using slightly different molecules as the acceptor, or by using different metal ions). Molecule-based magnetic materials often have a higher magnetization per unit mass ratio than atom-based magnets The cause of this is two fold: first, lighter nonmetal elements are often incorporated into the atomic structures, and second, the molecule-based magnetic compounds tend to have an open-framework type structure as opposed to the dense, tightly packed atomic lattices of atombased magnets

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Conclusion