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

The preparation of the shape-persistent carbosilane-functionalized porphyrins H2TPP(4-SiRR'Me)4, Zn(II)-TPP(4-SiRR'Me)4 (R = R' = Me, CH2CH=CH2, CH2CH2CH2OH; R = Me, R' = CH2CH=CH2, 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, CH2CH=CH2; R = Me, R' = CH2CH[double bond, length as m-dash]CH2) 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 0th and 1st 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.