Two iron(III)-based metal-organic frameworks (MOFs) are found to behave as efficient peroxidase mimics and catalyze the oxidation of different peroxidase substrates by H2O2 accompanied with significant color change in the solution. With these findings, a simple and sensitive colorimetric assay to detect H2O2 and ascorbic acid has been established.

The structural phase transitions in perovskite compounds were revived in the past decade by the emergence of a large number of perovskite compounds based on diatomic or multiatomic bridges, e.g. CN − , N 3 − , HCOO − , SCN − , and N(CN) 2 − , with various interesting properties for possible applications such as in dielectric switches, ferroelectrics, and multiferroics. Compared with the well-studied perovskite oxides and halides, these new perovskite compounds with larger bridges give rise to an increase in the complexity of structural variations as well as an opportunity to tailor the physical properties by taking advantage of the designable and tunable characteristics of the metal species, bridging ligands, and guest cation components.Here, we highlight the recent advances on the thermally-induced structural phase transitions of the perovskite compounds based on the diatomic or multiatomic bridges, focusing on the important role of the components in the phase transition behaviours as well as the intrinsic switching behaviours of physical properties.

Hydrothermal reactions of lanthanide(III) salts with m-sulfophenylphosphonic acid (H3L1) and 1,10-phenanthroline (phen) or N,N'-piperazinebis(methylenephosphonic acid) (H4L2) afforded six novel lanthanide(III) sulfonate-phosphonates based on tetranuclear clusters, namely, [La(2)(L1)2(phen)4(H2O)].4.5H2O (1), [Ln2(L1)2(phen)2(H2O)5].3H2O (Ln = Nd, 2; Eu, 3; Er, 4), and [Ln2(HL1)(H2L2)2(H2O)4].8H2O (Ln = La, 5; Nd, 6). Compounds 2-4 contain discrete tetranuclear lanthanide(III) cluster units in which four lanthanide(III) ions are bridged by two tridentate and two tetradentate phosphonate groups. In compound 1, the tetranuclear clusters are further interconnected into a 1D chain through the coordination of the sulfonate groups. The structures of compounds 5 and 6 can be viewed as a 3D architecture based on a different types of tetranuclear cluster units that are interconnected by bridging H2L2 anions. In the tetranuclear clusters of compounds 5 and 6, the four lanthanide(III) centers are interconnected by only two HL1 ligands. Compound 2 is a luminescent material in the near-IR region, whereas compound 3 displays a strong luminescent emission band in the red-light region. Magnetic property measurements of compounds 2-4 and 6 indicate that there are strong antiferromagetic interactions between magnetic centers within the cluster units.