Strong and Anisotropic Superexchange in the Single-Molecule Magnet (SMM) [(Mn6OsIII)-Os-III](3+): Promoting SMM Behavior through 3d-5d Transition Metal Substitution

Höke V, Stammler A, Bögge H, Schnack J, Glaser T. Strong and Anisotropic Superexchange in the Single-Molecule Magnet (SMM) [(Mn6OsIII)-Os-III](3+): Promoting SMM Behavior through 3d-5d Transition Metal Substitution. Inorganic Chemistry. 2014;53(1):257-268.The reaction of the in situ generated trinuclear triplesalen complex [(talen(t-Bu2))Mn-3(III)(solv)(n)](3+) with (Ph4P)(3)[Os-III(CN)(6)] and NaClO4 center dot H2O affords [(Mn6OsIII)-Os-III] (ClO4)(3) (= [{(talen(t-Bu2))Mn-3(III)}(2){Os-III(CN)(6)}](ClO4)(3)) in the presence of the oxidizing agent [(tacn)(2)Ni-III] (ClO4)(3) (tacn =1,4,7-triazacyclononane), while the reaction of [(talen(t-Bu2))-Mn-3(III)(solv)(n)](3+) with K-4[Os-II(CN)(6)] and NaClO4 center dot H2O yields [(Mn6OsII)-Os-III](ClO4)(2) under an argon atmosphere. The molecular structure of [(Mn6OsIII)-Os-III](3+) as determined by single-crystal X-ray diffraction is closely related to the already published [(Mn6Mc)-M-III](3+) complexes (M-c = Cr-III, Fe-III, Co-III, Mn-III). The half-wave potential of the Os-III/Os-II couple is E-1/2 = 0.07 V vs Fc(+)/Fc. The FT-IR and electronic absorption spectra of [(Mn6OsII)-Os-III](2+) and [(Mn6OsIII)-Os-III](3+) exhibit distinct features of dicationic and tricationic [(Mn6Mc)-M-III](n+) complexes, respectively. The dc magnetic data (mu(eff) vs T, M vs B, and VTVH) of [(Mn6OsII)-Os-III](2+) are successfully simulated by a full-matrix diagonalization of a spin-Hamiltonian including isotropic exchange, zero-field splitting with full consideration of the relative orientation of the D-tensors, and Zeeman interaction, indicating antiferromagnetic Mn-III-Mn-III interactions within the trinuclear triplesalen subunits (J(Mn-Mn)((1)) = -(0.53 +/- 0.01) cm(-1), (H) over cap (ex) = -2 Sigma(i(i)center dot(S) over cap (j)) as well as across the central Os-II ion (J(Mn-Mn)((2,cis)) = -(0.06 +/- 0.01) cm(-1), (J(Mn-Mn)((2,trans)) = -(0.15 +/- 0.01) cm(-1)), while D-Mn = -(3.9 +/- 0.1) cm(-1). The mu(eff) vs T data of [(Mn6OsIII)-Os-III](3+) are excellently reproduced assuming an anisotropic Ising-like Os-III-Mn-III superexchange with a nonzero component J(Os-Mn)((aniso)) = -(11.0 +/- 1.0) cm(-1) along the Os-Mn direction, while J(Mn-Mn) = -(0.9 +/- 0.1) cm(-1) and D-Mn = -(3.0 +/- 1.0) cm(-1). Alternating current measurements indicate a slower relaxation of the magnetization in the SMM [(Mn6OsIII)-Os-III](3+) compared to the 3d analogue [(Mn6FeIII)-Fe-III](3+) due to the stronger and anisotropic M-c-Mn-III exchange interaction

Social touch promotes interfemale communication via activation of parvocellular oxytocin neurons

Oxytocin (OT) is a great facilitator of social life but, although its effects on socially relevant brain regions have been extensively studied, OT neuron activity during actual social interactions remains unexplored. Most OT neurons are magnocellular neurons, which simultaneously project to the pituitary and forebrain regions involved in social behaviors. In the present study, we show that a much smaller population of OT neurons, parvocellular neurons that do not project to the pituitary but synapse onto magnocellular neurons, is preferentially activated by somatosensory stimuli. This activation is transmitted to the larger population of magnocellular neurons, which consequently show coordinated increases in their activity during social interactions between virgin female rats. Selectively activating these parvocellular neurons promotes social motivation, whereas inhibiting them reduces social interactions. Thus, parvocellular OT neurons receive particular inputs to control social behavior by coordinating the responses of the much larger population of magnocellular OT neurons. Charlet, Grinevich et al. show that social touch between female rats activates parvocellular oxytocin neurons; these neurons control social behavior by coordinating the responses of the much larger population of magnocellular oxytocin neurons