Covalently Linked Dimer of Mn3 Single-Molecule Magnets and Retention of Its Structure and Quantum Properties in Solution.

[Mn3O(O2CMe)3(dpd)3/2)]2(I3)2 has been obtained from the reaction of 1,3-di(pyridin-2-yl)propane-1,3-dione dioxime (dpdH2) with triangular [Mn(III)3O(O2CMe)(py)3](ClO4). It comprises two [Mn(III)3O](7+) triangular units linked covalently by three dioximate ligands into a [Mn3]2 dimer. Solid state dc and ac magnetic susceptibility measurements reveal that each Mn3 subunit of the dimer is a separate single-molecule magnet (SMM) with an S = 6 ground state and that the two SMM units are very weakly ferromagnetically exchange coupled. High-frequency EPR spectroscopy on a single crystal displays signal splittings indicative of quantum superposition/entanglement of the two SMMs, and parallel studies on MeCN/toluene (1:1) frozen solutions reveal the same spectral features. The dimer thus retains its structure and inter-Mn3 coupling upon dissolution. This work establishes that covalently linked molecular oligomers of exchange-coupled SMMs can be prepared that retain their oligomeric nature and attendant inter-SMM quantum mechanical coupling in solution, providing a second phase for their study and demonstrating the feasibility of using solution methods for their deposition on surfaces and related substrates for study.