Preparation and magnetic properties of low symmetry [Mn4O3] complexes withS=9/2

Controlled potential electrolysis (CPE) procedures have provided access to a family of distorted trigonal pyramidal [Mn4O3(O2CR)(4)(dbm)(3)] complexes (where R = C6H5 (1), C6H4-p-Me (2) and C6H4-p-7-MeO (3)) with an asymmetri c [Mn-4(mu (3)-O-3)(eta (2),mu (3)-O2CR)](6+) core. This results in C-s sym metry, lower than previous [Mn4O3X(O2CMe)(4)(dbm)(3)] complexes with C-3v s ymmetry. The dc magnetic susceptibility data of the C-s symmetry clusters a re similar to those of the C-3v symmetry complexes, and fits of the data sh ow a ferromagnetic coupling between Mn(III)-Mn(III) and antiferromagnetic c oupling between the three Mn(III)-Mn(IV) pairs, giving a resultant S = 9/2 ground state. The out-of-phase ac susceptibility indicates slow magnetizati on relaxation and that these molecules are single-molecule magnets at low t emperatures. (C) 2001 Elsevier Science Ltd. All rights reserved.