ChemPlusChem

Ready, set, go: The reactions of cationic transition-metal hydroxides, [M(OH)]⁺, of the first row with ammonia have been studied both experimentally and computationally. With the exception of scandium, all ions investigated react predominantly under NH bond activation (Cr–Ni, Zn), ligand exchange (Ni), or dehydrogenation (Ti, V). Regarding the efficiency, [Co(OH)]⁺ is taking a strong lead, followed by [Fe(OH)]⁺ and [Zn(OH)]⁺. Behind them are [Cr(OD)]⁺ and [Mn(OH)]⁺ while [Ti(OH)]⁺ and [V(OH)]⁺ ) are just one step behind.

Grow and change: Electrospray ionization (tandem) mass spectrometry was used to investigate the growth of bismuth–oxido clusters in solution, their ligand-exchange reactions, and their fragmentation in the gas phase (see figure). Clusters of different sizes and with different ligand shells were studied to identify typical growth intermediates and to examine dissociation reactions that proceed in the ligand shell as well as within the cluster core.

In a spin: LiNi_0.5Mn_1.5O₄ hierarchical nanofibers with diameters of 200–500 nm and lengths of up to several tens of micrometers were synthesized using low-cost starting materials by electrospinning combined with annealing. These nanofibers exhibit a favorable electrochemical performance. At a 0.5 C, they show an initial discharge capacity of 133 mA h g⁻¹ with a capacity retention over 94 % after 30 cycles (see figure).

Out of the blue: A reaction-based two-photon probe XanCu (see scheme) is reported for the selective detection of Cu⁺ in reducing aqueous environments. Copper(I)-mediated oxidative benzylic ether (CO) bond cleavage offers “switch-on” detection of the metal ion.

A supposed spectator ligand plays a crucial role in a seemingly simple ligand substitution reaction on palladium. Continuous monitoring by ESI-MS reveals all the details of an initial fast displacement of iodide by an incoming phosphine ligand, and of the recoordination of iodide that prompts the displacement of the bidentate ligand actually being substituted. An apparent double substitution and subsequent isomerization can be readily explained by two fast and one slow ligand substitution reactions (see figure).