Hybrid Molecular Material Exhibiting Single-Molecule Magnet Behavior and Molecular Conductivity

Two unique materials based on Mn4 single-molecule magnet (SMM) clusters (ST = 9) and integer or non-integer
average valent platinum maleonitriledithiolate (mnt2-) complexes, [{MnII2MnIII2(hmp)6(MeCN)2}{Pt(mnt)2}2][Pt(mnt)2]2·2MeCN (1) and [{MnII2MnIII2(hmp)6(MeCN)2}{Pt(mnt)2}4][Pt(mnt)2]2 (2), were synthesized by the material diffusion
method and electrochemical oxidation, respectively (hmp- = 2-hydroxymethylpyridinate). 1 and 2 are comprised
of four and six [Pt(mnt)2]n- units, respectively, in addition to a common MnII2MnIII2 double-cuboidal unit, [MnII2MnIII2(hmp)6(MeCN)2]4+ (hereinafter [Mn4]4+). Among the [Pt(mnt)2]n- units, two units in 1 and four units in 2 are
coordinated with the [Mn4]4+ unit, forming a 1D chain of {−[Mn4]−[Pt(mnt)2]2−} for 1 and a discrete subunit of
{[Pt(mnt)2]2−[Mn4]−[Pt(mnt)2]2} for 2. The other two [Pt(mnt)2]n- units, occupying void space of the packing, form
a stacking column with the coordinating [Pt(mnt)2]n- units, finally constructing hybrid frames of aggregates consisting
of [Mn4]4+ units and [Pt(mnt)2]n- units. Electronic conductivity measurements revealed that 1 is an insulator and 2
is a semiconductor with σ = 0.22 S·cm-1 at room temperature and an activation energy of 136 meV. Detailed
magnetic measurements proved that the [Mn4]4+ units in 1 and 2 behave as SMMs with an ST = 9 ground state
at low temperatures. There is no significant interaction between [Mn4]4+ units and [Pt(mnt)2]n- units, but interactions
between localized spins of [Pt(mnt)2]n- were detected even in 2 at low temperatures where the conductivity is
electronically insulated. 2 is the first example of a hybridized material exhibiting SMM behavior and electronic
conductivity.