Influence of meso-linker attachment on the formation of core···π interactions in urea-functionalized porphyrins

Abstract

The ability to cover the face of a porphyrin macrocycle selectively is an attractive feature for concepts such as catalysis and anion binding that are reliant on porphyrin core interactions. Herein, we have synthesized a family of mono-urea functionalized porphyrin complexes with intent to investigate their potential to form coreꞏꞏꞏπ interactions selectively to one face of the porphyrin macrocycle. By altering the distance between the urea moiety and the porphyrin through direct linkage or introducing a linker group we can control the formation of the core interactions. This is clearly seen in the crystal structure of 1-phenyl-3-(2-([10,15,20- triphenylporphyrinato]zinc(II)-5-yl)phenyl)urea where a unique face capping effect is demonstrated. In the crystal of this complex, there is a hydrogen-bonding network between the urea group and the axial methanol ligand forming head-to-tail aggregates with the Zn–O axis all molecules pointing in one direction.