X-ray scattering and electrical resistivity measurements were performed on SmNiC2. Satellite peaks characterized by an incommensurate wave vector (0.5, eta, 0) appear below 148 K, at which the resistivity shows an anomaly. The temperature dependence of thermal diffuse scattering above 148 K suggests critical phonon softening. These results indicate the formation of a charge-density-wave. The satellite peaks abruptly disappear and the resistivity sharply decreases when a ferromagnetic transition takes place at 17.7 K.

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The reductive carboxylation of α,β-unsaturated carbonyl compounds with carbon dioxide was studied. After the screening of various transition-metal complex catalysts and reducing agents, it was found that the combination of bis(acetylacetonato)cobalt(II) and diethylzinc could effectively afford the corresponding α-carboxylate in high yield from α,β-unsaturated nitriles. The product was obtained after esterification by trimethylsilyldiazomethane. The highly selective carboxylation was observed at the α-position in the present study.

The gaseous carbon dioxide incorporation reaction with α,β-unsaturated compounds was examined in the presence of a catalytic amount of bis(acetylacetonato)cobalt(II) and using diethylzinc as a reductant. After screening with various electron-withdrawing groups, both α,β-unsaturated nitriles and carboxamides were found to efficiently capture carbon dioxide to provide the corresponding carboxylates or malonates in good to excellent yields under mild conditions.

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