Constructing clusters with enhanced magnetic properties by assembling and distorting Mn3 building blocks.
The reaction of Mn(ClO4)(2).6H2O with Naphth-saoH2 (Naphth-saoH2=2-hydroxy-1-napthaldoxime) in pyridine (py) forms the complex [MnIII3O(Naphth-sao)3(py)3](ClO4).0.5py (.0.5py) in very good yields. Reaction of with NaO2CPh in EtOH produces the complex [MnIII6O2(Naphth-sao)6(O2CPh)2(EtOH)6].[MnIII6O2(Naphth-sao)6(O2CPh)2(EtOH)4].2.5Et2O.0.5H2O (.2.5Et2O.0.5H2O). Further reaction of complex with 1 equivalent of both NaN3 and Mn(ClO4)(2).6H2O in MeOH produces the complex [MnII2MnIII6O2(Naphth-sao)6(N3)6(MeOH)8].10MeOH (.10MeOH) that displays an S approximately 0 ground state. Ligand substitution of Naphth-saoH2 with Me-saoH2 in CH2Cl2-MeOH for the latter complex (Me-saoH2= 2-hydroxyphenylethanone oxime) forms the complex [MnII2MnIII6O2(Me-sao)6(N3)6(MeOH)8].10MeOH (.10MeOH) that displays an S=7 ground state with Ueff= 44.6 K. In all four complexes the main building block is the triangular {MnIII3O(R-sao)3} unit (R=Naphth for , and ; R=Me for ). The ligand substitution in triggers a structural distortion in the [Mn6] sub-core as observed by the increased (Mn-N-O-Mn) torsion angles in , switching the interactions from antiferro- to ferromagnetic, dramatically changing the ground-state of the octanuclear complexes from S=0 to 7.
Milios
Constantinos J
CJ
Department of Chemistry, University of Crete, 71003, Herakleion, Greece. komil@chemistry.uoc.gr
Inglis
Ross
R
Jones
Leigh F
LF
Prescimone
Alessandro
A
Parsons
Simon
S
Wernsdorfer
Wolfgang
W
Brechin
Euan K
EK