Strapped porphyrin rosettes based on the melamine–cyanuric acid motif. Self-assembly and supramolecular recognition

This paper describes studies on the synthesis, self-assembly behavior, and complexing properties of several strapped porphyrin-incorporated melamine–cyanuric or melamine-barbiturate-based rosette supramolecules in chloroform-d. Strapped porpyrin cyanuric acid and its Zn (II) complex were designed and synthesized. Both and could combine melamine derivatives or to afford porphyrin rosettes, which are more stable than the model rosette initially reported by Whitesides due to the larger size of the porphyrin unit. The new porphyrin rosettes could efficiently complex tripyridyl derivative through intermolecular, cooperative coordination between Zn (II) and pyridine. Two new pyridine-bearing barbiturates and were also synthesized. Mixing the identical amount of or with or in chloroform-d led to the formation of new isomeric rosettes as a result of different orientation of the pyridine unit of or in the rosettes. 1H NMR study also revealed that porpyrin-bearing rosette could complex pyridine-bearing rosette , leading to the formation of new two-layer-typed supramolecular architectures.