New family of Ln9Mn4 (Ln = Gd, Tb, Dy) and Y9Mn4 clusters from the use of methyl-2-pyridyl-ketone oxime in heterometallic Mn chemistry

A new family of [Ln(9)Mn(4)O(8)(OH)(4)(O2CPh)(17) (mpko)(4)] (Ln(III) = Gd (2), Tb (3), Dy (1); 2Mn(III), 2Mn(IV)) clusters and their diamagnetic Y III analog (1) have been obtained from the reaction of Mn(O2CPh)(2), LnCl(3) or YCl3, methyl-2-pyridyl-ketone oxime (mpkoH), and NMe4OH in a 2:2:2:4 M ratio in MeCl\l/CH2Cl2 (22:3 mL). The crystal structure of 4 center dot CH2Cl2 center dot 8MeCN reveals a very low-symmetry core comprising a [Dy2Mn2O4] cubane sandwiched between a {Dy2MnO4(OH)(4)} unit and an external Mn atom; alternatively, it can be described as a zig-zag 1-D {(MnOMnO2MnOMnIII)-O-IV-O-IV-O-III}(6+) unit sandwiched between Dy-5 and Dy-4 units. Fitting of the variabletemperature, solid-state de and ac magnetic susceptibility data on the Mn-4 unit of 1 revealed dominant antiferromagnetic (AF) Mn center dot center dot center dot Mn interactions: J(1) = -22.5(9) cm(-1), J(2) = -7.6(5) cm(-1), and J(3) = +0.30(3) CM-1, with , a constant g = 1.97, where J(1), J(2), and J(3) are the J((MnMnIV)-Mn-IV), J((MnMnIII)-Mn-IV) and J ((MnMnIII)-Mn-IV) exchange parameters, respectively. These parameters indicate an S = 4 ground state with S-T = 3 and S-T = 2 excited states at 2.4 and 4.2 cm(-1), respectively, above it. The many non-equivalent Mn center dot center dot center dot Gd interactions in Gd9Mn4 complex 2 were deduced to include both F and AF interactions leading to an S = 18 or 19 ground state. Complexes 3 and 4 exhibited frequency-dependent ac out-of-phase (chi '' M) signals below 4 K indicating them to be weak SMMs.

Automated summary

The translation describes a new family of [Ln-Mn-O-H-(O2CPh)-mpko] clusters and their properties, including magnetic interactions.