Hybridized complexes of [Mn2III] single-molecule magnets and Ni dithiolate complexes

The electrochemical oxidation of an acetone solution or acetonitrile (MeCN) solution containing Mn-2(III)(5-MeOsaltmen)(2)(H2O)(2)](PF6)(2) (5-MeOsaltmen(2) = N,N'-(1,1,2,2-tetramethylethylene)bis(5-methoxysalicylideneiminate)) and (NBu4)[Ni(dmit)(2)] (dmit(2) = 2-thioxo-1,3-dithiole-4,5-dithiolate) has yielded two unique hybrid materials in which [Mn-2](2+) single-molecule magnets (SMMs) possessing an S-T = 4 ground state and [Ni(dmit)(2)](n) molecules each possessing an average valence of ca.-0.29 are aggregated in a layer-by-layer form; [Mn-2(5-MeOsaltmen)(2)(acetone)(2)][Ni(dmit)(2)](7) center dot 4acetone (1) and [Mn-2(5-MeOsaltmen)(2)(MeCN)(2)][Ni(dmit)(2)](7) center dot 4MeCN (2). Compounds 1 and 2 have a similar structure to each other and crystallize in the triclinic P (1) over bar space group with inversion centers on the midpoint of Mn center dot center dot center dot Mn vector of the dimer and a Ni ion of one of [Ni(dmit)(2)](0.29) molecules (i.e., Z = 1). The [Mn-2](2+) unit has a typical Mn(III) out-of-plane dimeric core and is structurally consistent with the already reported [Mn-2] SMMs.Seven [Ni(dmit)(2)](0.29) units in the formula have a square-planar coordination geometry in common, and the charge distribution among them can be averagely assigned according to their local structures and IR spectra; thus, the formal charge for each molecule is -0.29. These two kinds of molecules,[Mn-2](2+) SMM units and [Ni(dmit)(2)](0.29) units, construct hybrid frames aggregating individually, where the latter units form a b-type stacking arrangement. Electronic conductivity measurements revealed that 1 and 2 are semiconductors with sigma(rt) = 1.6 S cm (1) and 2.8 S cm (1), respectively, at room temperature. The detail magnetic measurements proved that the [Mn-2](2+) units in 1 and 2 behave as S-T = 4 SMMs at low temperatures, although their conductivities are already insulated at such temperatures. (C) 2008 Elsevier B.V. All rights reserved.