TY - JOUR
T1 - Radical ligand-containing single-molecule magnets
AU - Demir, Selvan
AU - Jeon, Ie Rang
AU - Long, Jeffrey R.
AU - Harris, T. David
N1 - Funding Information:
This research was funded by the National Science Foundation through grants CHE-1111900 (JRL) and DMR-1351959 (TDH) .
Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2015
Y1 - 2015
N2 - Single-molecule magnets represent the ultimate size limit for spin-based information storage and processing; however, such applications require large spin relaxation barriers and blocking temperatures. Ongoing efforts to synthesize single-molecule magnets with higher barriers must take into consideration key physical parameters, such as spin ground state, S, and axial zero-field splitting parameter, D, which are both correlated to the barrier height. A third critical parameter that has received less attention is the exchange coupling constant, J. This constant determines the degree of separation between spin ground state and excited states, which must be sufficiently large in a single-molecule magnet to maintain slow magnetization dynamics at elevated temperatures, and also serves to shut down fast quantum relaxation pathways. Toward this end, one synthetic strategy to engender strong magnetic exchange is the incorporation of radical ligands into metal complexes. Within these complexes, the presence of direct exchange between paramagnetic ligand and metal units can result in exceptionally strong magnetic coupling, much stronger in fact than more common superexchange interactions. This review article provides a survey of radical ligand-containing single-molecule magnets, with a brief overview of other classes of metal-ligand radical complexes that could be exploited in the design of new single-molecule magnets. Furthermore, ligand-field and electronic structure considerations in dictating exchange strength and slow magnetic relaxation are highlighted, with the aim of helping to guide the synthesis of future radical ligand-containing single-molecule magnets with even stronger exchange coupling.
AB - Single-molecule magnets represent the ultimate size limit for spin-based information storage and processing; however, such applications require large spin relaxation barriers and blocking temperatures. Ongoing efforts to synthesize single-molecule magnets with higher barriers must take into consideration key physical parameters, such as spin ground state, S, and axial zero-field splitting parameter, D, which are both correlated to the barrier height. A third critical parameter that has received less attention is the exchange coupling constant, J. This constant determines the degree of separation between spin ground state and excited states, which must be sufficiently large in a single-molecule magnet to maintain slow magnetization dynamics at elevated temperatures, and also serves to shut down fast quantum relaxation pathways. Toward this end, one synthetic strategy to engender strong magnetic exchange is the incorporation of radical ligands into metal complexes. Within these complexes, the presence of direct exchange between paramagnetic ligand and metal units can result in exceptionally strong magnetic coupling, much stronger in fact than more common superexchange interactions. This review article provides a survey of radical ligand-containing single-molecule magnets, with a brief overview of other classes of metal-ligand radical complexes that could be exploited in the design of new single-molecule magnets. Furthermore, ligand-field and electronic structure considerations in dictating exchange strength and slow magnetic relaxation are highlighted, with the aim of helping to guide the synthesis of future radical ligand-containing single-molecule magnets with even stronger exchange coupling.
KW - Exchange coupling
KW - Radical ligands
KW - Redox-active ligands
KW - Single-molecule magnets
KW - Zero-field splitting
UR - http://www.scopus.com/inward/record.url?scp=84930945186&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84930945186&partnerID=8YFLogxK
U2 - 10.1016/j.ccr.2014.10.012
DO - 10.1016/j.ccr.2014.10.012
M3 - Review article
AN - SCOPUS:84930945186
SN - 0010-8545
VL - 289-290
SP - 149
EP - 176
JO - Coordination Chemistry Reviews
JF - Coordination Chemistry Reviews
IS - 1
ER -