One-Step Preparation of Fe/N/C Single-Atom Catalysts Containing Fe-N4 Sites from an Iron Complex Precursor with 5,6,7,8-Tetraphenyl-1,12-Diazatriphenylene Ligands.

Fe/N/C single-atom catalysts containing Fe-Nx sites prepared by pyrolysis are promising cathode materials for fuel cells and metal-air batteries due to their high oxygen reduction reaction (ORR) activities. We have developed iron complexes containing N2- or N3-chelating coordination structures with preorganized aromatic rings in a 1,12-diazatriphenylene framework tethering bromo substituents as precursors to precisely construct Fe-N4 sites in an Fe/N/C catalyst. One-step pyrolysis of the iron complex with carbon black forms atomically dispersed Fe-N4 sites without iron aggregates. X-ray absorption spectroscopy (XAS) and electrochemical measurements revealed that the iron complex with N3-coordination is more effectively converted to Fe-N4 sites catalyzing ORR with a TOF value of 0.21 e site-1 s-1 at 0.8 V vs. RHE. This indicates that the formation of Fe-N4 sites is controlled by precise tuning of the chemical structure of the iron complex precursor.

Interactions between dehydrobenzo[12]annulene (DBA) and gas molecules: do the preorganized acetylenes work cooperatively?

Intermolecular interactions of the cyclic conjugated molecule (DBA) with hydrogen, nitrogen and carbon dioxide molecules were evaluated by high level ab initio calculations.

Right- and left-handedness of 2(1) symmetrical herringbone assemblies of benzene.

A universal method to determine handedness of 2(1) helical assemblies composed of planar aromatic molecules is proposed and demonstrated by taking P2(1)/c and Pbca crystals of benzene, the simplest aromatic molecule, as examples.

Supramolecular tilt chirality derived from symmetrical benzene molecules: handedness of the 2(1) helical assembly.

Achiral molecules can form aggregates with chirality. This depends on the relative position of the molecules, in other words, the tilt of the molecules (so-called supramolecular tilt chirality). In this paper, we describe supramolecular chirality appearing in a 2(1) column composed of symmetrical benzene molecules, which is formed in the host cavity of inclusion crystals of cholic acid. Moreover, we determined the handedness, that is, right or left, of the 2(1) helical column of benzene on the basis of the molecular tilt. Determination of the 2(1) helical handedness was performed on assemblies of other benzene derivatives in cholic acid crystals and benzene assemblies in other host frameworks selected from the Cambridge Structural Database. Finally, we demonstrated complementarity of the handedness between the 2(1) symmetrical host framework of cholic acid and the benzene column.