Search for new iron single-molecule magnets |
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| Institution: | 1. Department of Chemistry and Biochemistry – 0358, University of California at San Diego, La Jolla, CA 92093-0358, USA;2. Department of Physics, University of Florida, Gainesville, FL 32611, USA;3. Laboratoire Louis-Neél-CNRS, 25 Avenue des Martyrs, 38042 Grenoble Cedex 9, France;4. Department of Chemistry, University of Delaware, Newark, DE 19716, USA;5. Department Chemistry, University of Florida, Gainesville, FL 32611-7200, USA;1. Faculty of Chemistry and Chemical Technology, Department of Chemistry, Moldova State University, 60 Mateevici Street, MD 2009 Chisinau, Republic of Moldova;2. Institute of Applied Physics, Academy of Sciences, 5 Academiei Street, MD 2028 Chisinau, Republic of Moldova;1. Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), Mianyang 621900, PR China;2. China Academy of Engineering Physics (CAEP), Mianyang 621900, PR China;1. Division of Polymer Engineering, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia;2. Faculty of Engineering Technology, Universiti Malaysia Perlis (UniMAP), P.O Box 77, D/A Pejabat Pos Besar, Kangar, Perlis, 01000, Malaysia;1. Department of Chemistry, University College of Science, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India;2. School of Chemistry, The University of Reading, P.O. Box 224, Whiteknights, Reading RG 66AD, UK;3. Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán, 2, 46980 Paterna, Valencia, Spain |
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| Abstract: | The synthesis, X-ray structure, and magnetic properties of a trinuclear iron complex with the formulation Fe3O2Cl2(4,7-Me-phen)6](BF4)3 (complex 1) are reported. DC magnetic susceptibility measurements show the Fe atoms are antiferromagnetically coupled, yielding an S=5/2 ground state. An investigation as to whether complex 1 exhibits the properties associated with single-molecule magnetism was undertaken. Detailed high frequency EPR experiments were carried out to determine the spin Hamiltonian parameters associated with the S=5/2 spin ground state. Analysis of the temperature dependence of the transitions seen with the magnetic field oriented along the easy axis (z axis) of the Fe3 complex confirm that the molecule has a positive D value. A fit of the frequency dependence of the resonances afforded the following spin Hamiltonian parameters: S=5/2, gz=1.95, gx=gy=2.00, D=0.844 cm?1, E=±0.117 cm?1, and B4 0=?2.7×10?4 cm?1. Low temperature magnetization versus magnetic field data confirm that complex 1 has no barrier towards magnetization reversal. Thus, it is concluded that, due to the positive D-value, complex 1 is not a single-molecule magnet. |
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