Synthesis, crystal structure, and nonlinear optical behavior of β-unsubstituted meso-meso E-vinylene-linked porphyrin dimers

A vinylene-linked porphyrin dimer, with no substituents at the beta-positions, has been synthesized by Cul/CsF promoted Stille coupling. In the crystal structure of this dimer, the C2H2 bridge is twisted by 45 degrees relative to the plane of the porphyrins. The absorption, emission spectra, and electrochemistry reveal substantial porphyrin-porphyrin T-conjugation. The triplet excited-state absorption spectrum of this dimer makes it suitable for reverse saturable absorption at 710-900 nm.