A macrocyclic host molecule possessing a nanocavity with two Ag(I) centers for guest binding and four anthracene walls has been developed. This dimetal-macrocycle forms stable inclusion complexes with ditopic aromatic guest molecules, [2.2]paracyclophane, and ferrocene, in solution and/or in the solid state through Ag-π interactions within the nanocavity. The binding constants for the inclusion complexes were found to range roughly from 10(4) to 10(9) M(-1). Electrochemical measurement revealed that the oxidized form of the included cationic ferrocene was less stabilized due to the direct binding to the cationic two Ag(I) centers.

Stacked rings: A diamond-shaped macrocycle with two inward phenanthroline ligands and outward long alkyl chains, and its Pd(II) complex form organic and organometallic fibrous aggregates, respectively, as revealed by NMR, UV/Vis, AFM, and TEM measurements. The most likely structures are face-to-face stacked macrocycles, generating nanotubes.

A phenanthroline-based macrocycle 1 has been newly developed which has two chemically equivalent metal chelating sites within the spatially restricted cavity for dinuclear metal arrangement. The macrocycle 1 reacts with Zn(CF(3)CO(2))(2) or ZnCl(2) to form homodinuclear Zn(II)-complexes. A single-crystal X-ray structural analysis of the resulting Zn(2)1(CF(3)CO(2))(4) determined the complex structure in which two Zn(II) ions are bound by two phenanthroline sites and two CF(3)CO(2)(-) ions bind to each Zn(II) ion in a tetrahedral geometry. Similarly, a homodinuclear Cu(I)-macrocycle was formed from 1 and Cu(CH(3)CN)(4)BF(4). Notably, from 1 and an equimolar mixture of Cu(CH(3)CN)(4)BF(4) and Zn(CF(3)CO(2))(2), a heterodinuclear Cu(I)-Zn(II)-macrocycle was exclusively formed in high yield (>90%) because of the relatively low stability of the dinuclear Cu(I)-macrocycle. A heterodinuclear Ag(I)-Zn(II)-macrocycle was similarly formed with fairly high selectivity from a mixture of Ag(I) and Zn(II) ions. Such selective heterodinuclear metal arrangement was not observed with other combinations of M-Zn(II) (M = Li(I), Mg(II), Pd(II), Hg(II), La(III), and Tb(III)).

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Lubricant oils can autoxidize due to contact with air and can be accelerated by heat and catalyzed with metal ion impurities. Therefore, new antioxidant additives are needed. Carbon nanomaterials exhibit excellent thermal oxidation resistance and can act as additives for lubricant oils to extend their operational lifetime. In this work, we studied the autoxidation behavior of a mixture of C60/C70 clusters in mineral oil (MO) containing different amounts of toluene during mixing. The addition of toluene during mixing increased the ratio of C60/C70 and the cluster size. The oil-fullerene mixtures (MO/C60/70) were heated at 150 °C for 48 h under magnetic stirring. FTIR analysis and TGA showed that the initial oxidation rate and high thermal oxidation (ca. 375 °C) decreased with the addition of fullerenes. Ball on disk friction tests showed that fullerenes effectively reduced the friction coefficient, favored by smaller C60/70 clusters. The obtained results demonstrate that small fullerene clusters with high C70 content can be achieved without the addition of toluene in mineral oil and exhibit higher antioxidation, and lower friction coefficient. Thus, fullerenes could be of high interest as an additive for lubricant oils.