It was demonstrated experimentally that nonplanar iron porphyrins can be induced to undergo a conversion in their electronic configuration to form a cross-hybrid transition by compressing the macrocyclic core size for the central metal ion. A series of monostrapped iron porphyrins were used as model systems, and their electronic properties were probed using electron spin resonance and differential spectral analyses. These results indicate that the formation of a cross-hybrid transition stage is related to the stability of the high-valence state and potent oxidizing ability of the central iron ion.

Ruffle- and dome-type porphyrins were developed as model systems to investigate the role of deformation mode and degree of distortion in heme. Their crystal structures revealed that as the degree of distortion increases, cavity size can be contracted in the ruffle mode and expanded in the dome mode, and the size of cavity can exceed the limit of free metal ions from the fourth period (see scheme).

We report a crystalline compound 2-azido-4,6-dimethoxy-1,3,5-triazine (ADT) as an intrinsically safe, highly efficient, and shelf-stable diazo-transfer reagent. Because the decomposition of ADT is an endothermal process (Δ H = 30.3 kJ mol), ADT is intrinsically nonexplosive, as proved by thermal, friction, and impact tests. The diazo-transfer reaction based on ADT gives diazo compounds in excellent yields within several minutes at room temperature. ADT is very stable upon >1 year storage under air at room temperature.

Five categories of valuable N-containing compounds can be selectively synthesized by the catalytic tandem reduction of nitroarenes with in situ generated Pd nanoclusters as the catalyst.