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The effect of partial replacement of Cu ions by small Be cations with no d-electrons in CaCu3Ti4O12ceramics was studied over the temperature range from 90 K to 800 K. Dielectric constant of CaCu3(1−x)Be3xTi4O12decreases exponentially with increasing x as ε′ =4000 + exp(-x/0.023); by 5% of Be-doping, the relaxation time and activation energy decrease to values of 50% and 92% compared with those in pure CCTO, respectively. The weakened hybridization in Cu-O bonds by Be-doping suppresses dielectric properties. This evidence indicates that the role ofA′-site ions is important for anomalous dielectric response in CaCu3Ti4O12at high temperatures. [ABSTRACT FROM AUTHOR]

The regioselective carbonylation of unactivated C(sp3)-H bonds of aliphatic amides was achieved using Ru3(CO)12 as a catalyst. The presence of a 2-pyridinylmethylamine moiety in the amide is crucial for a successful reaction. The reaction shows a preference for C-H bonds of methyl groups as opposed to methylene C-H bonds and tolerates a variety of functional groups. The stoichiometric reaction of an amide with Ru3(CO)12 gave a dinuclear ruthenium complex in which the 2-pyridinyl-methylamino moiety was coordinated to the ruthenium center in an N,N manner. [ABSTRACT FROM AUTHOR]

A novel method for the cyclocarbonylation of unactivated C-H bonds is developed by using the catalyst Ru3(CO)12. [ABSTRACT FROM AUTHOR]