Aggregation-induced emission (AIE) luminogens with photochromic properties show strong potential in molecular switches, photo-controllable materials, photo-patterning, etc. In this paper one Schiff-base compound 1 exhibited reversible photo-controllable colour changes in solid states due to the typical ESIPT effect: the crystal turned from colourless to yellow after ultraviolet light irradiation and became colourless again in the dark. Second, 1 presented a good aggregation-induced emission (AIE) activity in aqueous solution. Third, highly efficient light-harvesting systems are successfully fabricated in aqueous solution based on AIE(1) and rhodamine B, where AIE(1) acts as an energy donor and rhodamine B acts as an acceptor. Fourth, addition of Al³⁺ or Cu²⁺ ions destructed the N⋯H–O hydrogen bond and induced the rearrangement or destruction of AIE(1) with a different emission. Last, theoretical calculations of deprotonated 1 indicated that the protons on phenolic hydroxyl groups have a great influence on the fluorescence properties of 1. These results demonstrated that compound 1 is a multi-functional organic luminescent material exhibiting excellent photochromism, light-harvesting and AIE properties.

Searches for planar hexacoordinate carbon (phC) species comprised of only seven atoms uncovered good CX₃M₃ prototypes, D_3h CN₃Be₃ ⁺ and CO₃Li₃ ⁺. The latter is the global minimum. It might also be possible to detect the deep-lying kinetically-viable D_3h CN₃Be₃ ⁺ local minimum, based on its robustness toward molecular dynamic simulations and its very high isomerization barrier.

Non-spherical distributions of ligand atoms in coordination complexes are generally unfavorable due to higher repulsion than for spherical distributions. To the best of our knowledge, non-spherical heptagonal bipyramidal nonacoordination is hitherto unreported, because of extremely high repulsion among seven equatorial ligand atoms. Herein, we report the computational prediction of such nonacoordination, which is constructed by the synergetic coordination of an equatorial hepta-dentate centripetal ligand (B₇O₇) and two axial mono-dentate ligands (-BO) in the gear-like mono-anionic complexes [OB-M©B₇O₇-BO]^– (M = Fe, Ru, Os). The high repulsion among seven equatorial ligand B atoms has been compensated by the strong B–O bonding. These complexes are the dynamically stable (up to 1500 K) global energy minima with the HOMO-LUMO gaps of 7.15 to 7.42 eV and first vertical detachment energies of 6.14 to 6.66 eV (being very high for anions), suggesting their high probability for experimental realization in both gas-phase and condensed phases. The high stability stems geometrically from the surrounded outer-shell oxygen atoms and electronically from meeting the 18e rule as well as possessing the σ + π + δ triple aromaticity. Remarkably, the ligand-metal interactions are governed not by the familiar donation and backdonation interactions, but by the electrostatic interactions and electron-sharing bonding.