Reversible, carbon dioxide mediated chemical hydrogen storage was first demonstrated using a heterogeneous Pd catalyst supported on mesoporous graphitic carbon nitride (Pd/mpg-C 3 N 4 ). The Pd nanoparticles were found to be uniformly dispersed onto mpg-C 3 N 4 with an average size of 1.7 nm without any agglomeration and further exhibit superior activity for the dehydrogenation of formic acid with a turnover frequency of 144 h À1 even in the absence of external bases at room temperature. Initial DFT studies suggest that basic sites located at the mpg-C 3 N 4 support play synergetic roles in stabilizing reduced Pd nanoparticles without any surfactant as well as in initiating H 2 -release by deprotonation of formic acid, and these potential interactions were further confirmed by X-ray absorption near edge structure (XANES). Along with dehydrogenation, Pd/mpg-C 3 N 4 also proves to catalyze the regeneration of formic acid via CO 2 hydrogenation. The governing factors of CO 2 hydrogenation are further elucidated to increase the quantity of the desired formic acid with high selectivity.

Amine-functionalized mesoporous silica-supported ultrasmall Pd nanoparticles catalyze hydrogen evolution from formic acid at ambient temperature.

Dynamic kinetic resolution (DKR) is an attractive process for the transformation of racemic mixtures into optically active compounds. For successful DKR, efficient racemization is required while the kinetic resolution is proceeding. This Microreview mainly summarizes the recent developments in the DKR of alcohols and amines, based on metal-catalyzed racemization and enzymatic acylation in a single reaction vessel.

[1] This paper reports on several substorms observed under northward interplanetary magnetic field (IMF) conditions, the intensity of which was at least as significant as that of typical substorms under moderately southward IMF conditions. Such northward IMF periods were identified during the recovery phase of three strong storms. In the case of each storm, two or more substorms occurred successively, being separated by $1.8-5 h, while the IMF condition continued persistently northward. The substorms are clearly evidenced by auroral and other complementary observations. For the most intense substorms, the auroral breakup occurred at the magnetic latitude of $58°, and for the others it was between 60°and 65°. The polar cap size prior to each onset was substantial despite the northward IMF conditions. The auroral expansion following each onset lasted from a few up to several magnetic local time hours and exhibited a clear poleward expansion feature. For most of the events studied, geosynchronous magnetic dipolarizations preceded by field stretching and/or energetic particle injections occurred. The occurrence of such (intense) substorms implies that a certain (large) amount of energy remains in the tail even under northward IMF conditions. The occurrence of two or more successive substorms further implies that even after the release of a certain amount of energy triggered by the substorm, the tail can still have a substantial amount of energy left, which can be released by a subsequent substorm(s). We conjecture that an intense substorm during a northward IMF period can be expected when such a period belongs to the recovery phase of an intense storm mainly because of large energy loading done by preceding southward IMF B z during the storm's main (and some early recovery) phase. In addition we argue that substorm energy can also be supplied by other mechanisms of the solar wind-magnetosphere coupling under northward IMF conditions such as dayside reconnection in the presence of a substantial IMF B y component.

Shine a light: A fluorescent light‐induced synthetic method for the title compounds has been developed and the chemoselective nature of the reaction is highlighted by the observation of the cis/trans isomers of various N‐unsubstituted imines. The synthetic utility of this method is demonstrated by the one‐pot imine formation/asymmetric allylation sequence of benzyl azide catalyzed by 1. (Ipc=isopinocampheyl).