Bent Dithienoporphyrin(2.1.2.1): Synthesis, Structure, Optical and Electronic Properties, and Metal Complexation

Four kinds of isomeric dithienoporphyrins(2.1.2.1) were prepared using two di(1H-pyrrolo-2-yl)thiophenes as building blocks and two arylaldehydes under mild acid-catalyzed conditions. The molecular conformation and optical and electronic properties of dithienoporphyrins(2.1.2.1) were investigated by NMR spectroscopy, X-ray diffraction, UV-vis absorption spectroscopy, electrochemical measurements, and theoretical calculations. The crystal structure of [2,3]F5TP has the largest angle between the two planes of the dipyrrin units among dibenzo-/dinaphthoporphyrins(2.1.2.1). This result indicates that the incorporation of thiophene subunits into a porphyrin(2.1.2.1) macrocycle results in the alteration of the molecular geometry to a more planarized structure. Dithienoporphyrin(2.1.2.1) is found to act as a ligand that can form metal complexes with nickel(II), copper(II), and palladium(II) ions. The molecular structures of the dithienoporphyrin(2.1.2.1) metal complexes exhibited bent molecular conformations. The red-shifted absorption, reversible redox processes, and theoretical calculations indicated that the electronic properties of the dithienoporphyrin(2.1.2.1) metal complexes are controlled by the inserted metal ions.

Automated summary

Four kinds of isomeric dithienoporphyrins(2.1.2.1) were synthesized using two di(1H-pyrrolo-2-yl)thiophenes as building blocks and two arylaldehydes under mild acid-catalyzed conditions. The conformation and properties of the dithienoporphyrins(2.1.2.1) were investigated using various spectroscopic techniques and theoretical calculations. The incorporation of thiophene subunits resulted in a more planarized molecular structure, and the dithienoporphyrin(2.1.2.1) acted as a ligand for metal ions, leading to bent molecular conformations.