Multidimensional, conjugated building blocks have been formed through the axial coordination of polyynes to the central Ga atom of tetraarylporphyrins.E lectron deficient pentafluorophenyl substituents in the meso-positions provide more stable s-acetylide complexes to Ga than analogous structures with tert-butylphenyl groups.Mono-, di-, and triynes have been used, including ap yridyl endcapped diyne that allows for formation of porphyrin triads through coordination of the pyridyl ligand to aR uporphyrin. Figure 1. a) Porphyrin oligomer formed by Vernier templation. [8] b) Porphyrin dimer as the subunit of amolecularbox. [9] c) Schematic construction perpendiculart oporphyrin plane via metal acetylides, and d) Known axial metal acetylidesw ith pentacoordinate Ga-, In-, and Fe-metalloporphyrins (TPP, R' = C 6 H 5 ,R= H; OEP, R' = H, R = C 2 H 5 ).

The hierarchical synthesis of three porphyrin and four bisporphyrin derivatives is presented. This strategy relies on the incorporation of linkers based on azo moieties appended with pyridyl and/or acetylenic groups that facilitate axial coordination to Ga‐ and Ru‐metalloporphyrins. These porphyrinic systems allow for a quantitative analysis of the effects of diamagnetic anisotropy (DA) by using 1H NMR spectroscopic and X‐ray crystallographic analyses. A simple power‐law relationship between the proton chemical shift and the distance from the porphyrin core is experimentally outlined, which confirms previous theoretical predictions and shows that the limit of DA is about 2 nm. Photophysical properties of the azo‐linked porphyrins are analyzed by UV/Vis spectroscopy, showing that significant cis–trans isomerization is not observed for azo ligands bound only to Ga‐porphyrins. Incorporation of Ru‐porphyrins to an azo ligand facilitates photoswitching behavior, but the process faces competition from decarbonylation of the Ru‐porphyrin, and appreciable switching is only documented for GaL1Ru.

Multidimensional, conjugated building blocks have been formed through the axial coordination of polyynes to the central Ga atom of tetraarylporphyrins. Electron deficient pentafluorophenyl substituents in the meso‐positions provide more stable σ‐acetylide complexes to Ga than analogous structures with tert‐butylphenyl groups. Mono‐, di‐, and triynes have been used, including a pyridyl endcapped diyne that allows for formation of porphyrin triads through coordination of the pyridyl ligand to a Ru porphyrin.