RESUMO
Single-ion magnets (SIMs) are potential building blocks of novel quantum computing devices. Unique magnetic properties of SIMs require effective separation of magnetic ions and can be tuned by even slight changes in their coordination sphere geometry. We show that an additional level of tailorability in the design of SIMs can be achieved by organizing magnetic ions into supramolecular architectures, resulting in gaining control over magnetic ion packing. Here, γ-cyclodextrin was used to template magnetic Co(II) and nonmagnetic auxiliary Li(+) ions to form a heterometallic {Co, Li, Li}4 ring. In the sandwich-type complex [(γ-CD)2Co4Li8(H2O)12] spatially separated Co(II) ions are prevented from superexchange magnetic coupling. Ac/dc magnetic and EPR studies demonstrated that individual Co(II) ions with positive zero-field splitting exhibit field-induced slow magnetic relaxation consistent with the SIMs' behavior, which is exceptional in complexes with easy-plane magnetic anisotropy.
RESUMO
The rotational spectrum of n-propanol (n-CH(3)CH(2)CH(2)OH) was studied with several techniques of contemporary broadband rotational spectroscopy at frequencies from 8 to 550 GHz. Rotational transitions in all five conformers of the molecule, Gt, Gg, Gg', Tt, and Tg, have been unambiguously assigned. Over 6700 lines of the Gt, Gg, and Gg' species, for quantum number values reaching K(a) = 33 and J = 67, were fitted in a joint analysis leading to the determination of DeltaE(Gg-Gt) = 47.82425(25) cm(-1) and DeltaE (Gg'-Gg) = 3.035047(11) cm(-1). Stark effect measurements in supersonic expansion were used to further confirm the assignment. The results are compared with those for the ethanol molecule and with ab initio calculations, allowing several inferences to be drawn concerning the differences in the large amplitude torsional potential of the hydroxyl group in the two molecules.