Porphyrins with a carbosilane dendrimer periphery as synthetic components for supramolecular self-assembly

Abstract

The preparation of the shape-persistent carbosilane-functionalized porphyrins H₂TPP(4-SiRR′Me)₄, Zn(II)-TPP(4-SiRR′Me)₄ (R = R′ = Me, CH₂CHCH₂, CH₂CH₂CH₂OH; R = Me, R′ = CH₂CHCH₂, CH₂CH₂CH₂OH; TPP = tetraphenyl porphyrin), H₂TPP(4-Si(C₆H₄-1,4-SiRR′Me)₃)₄, and Zn(II)-TPP(4-Si(C₆H₄-1,4-SiRR′Me)₃)₄ (R = R′ = Me, CH₂CHCH₂; R = Me, R′ = CH₂CHCH₂) using the Lindsey condensation methodology is described. For a series of five samples their structures in the solid state were determined by single crystal X-ray structure analysis. The appropriate 0^th and 1^st generation porphyrin-based 1,4-phenylene carbosilanes form 2D and 3D supramolecular network structures, primarily controlled by either π–π interactions (between pyrrole units and neighboring phenylene rings) or directional molecular hydrogen recognition and zinc–oxygen bond formation in the appropriate hydroxyl-functionalized molecules. UV-Vis spectroscopic studies were carried out in order to analyze the effect of the dendritic branches on the optical properties of the porphyrin ring.