The synthesis and characterisation of polymetallic transition metal complexes towards single-molecule magnets

QD Chemistry

Graham, Kristoffer ; Murrie, Mark

University:University of Glasgow

Department:School of Chemistry

关键词: Single Molecule Magnets, Polymetallic Transition Metal Complexes, Magnetism, Coordination Complexes;   

Others  :  http://theses.gla.ac.uk/1351/1/2009GrahamPhD.pdf

来源: University of Glasgow

【 摘 要 】

The synthesis and characterisation of sixteen new complexes are reported. The use of the ligand edte (((HOCH2CH2)2NCH2CH2N(CH2CH2OH)2)), H4L1) has resulted in five new iron complexes. Two Fe6 complexes and an Fe3 complex display non-zero ground states of S = 5 and S = 3 respectively. An Fe12 complex which displays a unique cluster topology and an Fe2 dimer are also reported, both with a ground state S = 0.A further six new iron clusters are reported using bicine(((HOCH2CH2)2N(CH2COOH)), H3L2). Two homeo-structural Fe6 complexes display spin ground states of S = 5 and S = 4, whereas a mixed-valence Fe6 cluster has a ground state of S = 3 and a large magnetic anisotropy. Further measurements are needed below 1.8 K to confirm any SMM behaviour. In addition an Fe12 cluster with a unique core topology possesses a spin ground state of S = 0. Two remaining Fe6clusters are still to be magnetically characterised.The final three iron complexes are reported using the ligand tricine (((HOCH2)3CNHCH2COOH)H4L3). Fe9 posesses a ground state S = 11/2. Magnetic characterisation of Fe7 and Fe12 complexes are still needed to determine the spinground state of these clusters.Two new Cr(III) clusters are reported using bis-tris (((HOCH2)3CN(CH2CH2OH)2),H4L4), the first a simple monomer and the second a Cr4 tetramer characterised with a spin ground state S = 0.