This review highlights the recent progress in the production of hydrogen using a metal oxynitride photocatalyst under visible light irradiation.

A family of iron(III) spin crossover complexes with different counteranions, [Fe(qsal-F) − 5, or NCS − 6) have been prepared. All compounds are isostructural and crystallize (triclinic P1̅ space group) with two independent iron(III) centers (Fe1 and Fe2) in the asymmetric unit. No solvent molecules are found in the crystal lattice, allowing us to directly probe the relative influence of anion variation on the spin crossover characteristics. The crystal packing is governed by three types of π−π interactions (type A, type B, and type C), which form undulating 1D chains. Additional interactions (π−F, C−H•••O/F, and P4AE) connect the neighboring chains to form a complex supramolecular network. Hirshfeld surface analysis supports these findings. The anions are located between the cationic [Fe(qsal-F) 2 ] + chains; hence, similar interchain distances (d chain ) are observed irrespective of the anion. However, the interplane distances (d plane ) are influenced by the crystal packing and increase proportionally with the anion size. Magnetic studies reveal that smaller anions tend to stabilize the low-spin state (NO 3 − 3, ClO 4 − 4, and BF 4 − 5), while larger anions (PF 6 − 1 and OTf − 2) exhibit lower transition temperatures (T onset for 1 = 200 K and T for 2 = 190 K) and gradual spin crossovers. The anomaly is 6, where, despite having the smallest anion, it exhibits the lowest transition temperature with magnetic hysteresis in the first step (T 1/2 ↑ = 170 K and T 1/2 ↓ = 157 K). This suggests the size, shape, and supramolecular connectivity of the anion all influence the magnetic properties.

No abstract

Molecular devices based on spin-crossover (SCO) compounds are important targets for molecular electronics. In this study, six air-stable FeIII complexes have been prepared: [Fe­(naphBzen)2]Cl (1), [Fe­(naphBzen)2]­Cl·0.5hexane (1·0.5hexane); [Fe­(naphBzen)2]­Cl·2CHCl3·1.15hexane (1·2CHCl3·1.15hexane), [Fe­(naphBzen)2]Br (2), [Fe­(naphBzen)2]­Br·0.5hexane (2·0.5hexane), and [Fe­(naphBzen)2]­Br·2CHCl3 (2·2CHCl3). The hexane solvates are isostructural, crystallizing in the tetragonal space group I41/a. Weak van der Waals interactions between the cations result in the Fe1 and Fe2 centers packing into chiral chains and exhibiting two-step SCO. In contrast, the nonisostructural CHCl3 solvates have a single Fe center and crystallize in the triclinic space group P1̅ and are LS up to 350 K. The solvent-free systems are also not isostructural with [Fe­(naphBzen)2]­Cl, crystallizing in the triclinic space group P1̅, while [Fe­(naphBzen)2]Br undergoes a phase transition from tetragonal P43 to P43212 upon heating from 150 to 280 K. In both cases the compounds are trapped in the LS state. Magnetic data reveals that SCO occurs only in the hexane solvates, indicating that even very weak interactions can be critical in observing spin-crossover behavior.

LC-MS chromatogram of metabolites and their respective structures.