As eries of largely p-extended multichromophoric molecules including cross-conjugated, half cross-conjugated, conjugation-interrupted and linearly conjugated systems were synthesized and characterized.T hese multichromophoric molecular systems revealed interesting structural-property relationships.B isporphyrin-fused pentacenes Pen-1 b and Pen-2 a showed rich redox chemistry with 7a nd 8o bservable redox states,r espectively.T he linearly-conjugated bisporphyrin-fused pentacenes (Pen-1 b and Pen-2 a)p ossess much narrower HOMO-LUMO gaps (1.65 and 1.42 eV redox, respectively) and higher HOMO energy levels than those of their pentacene analogues (2.23 and 2.01 eV redox, respectively), similar to those of muchl ess stable hexacenes and heptacenes.A ne stimated half-life of > 945 hw as obtained for bisporphyrin-fused pentacene Pen-2 a,w hich is much longer than that of its pentacene analogue (BPE-P,h alf-life, 33 h).

Push–pull opp-dibenzoporphyrins with a phenylethynyl bridge were newly synthesized as sensitizers for dye-sensitized solar cells, giving power conversion efficiencies up to 6.7%, close to that of the N719 dye under similar conditions.

A new synthetic method to fuse benzo[4,5]imidazo[2,1-a]isoindole to the porphyrin periphery through the β, β-positions has been developed, and its impact on the aromaticity and electronic structures is investigated. Reactivity...

Unsymmetric pentacenequinone-fused (cross-conjugated) and pentacene-fused (linear-conjugated) porphyrins were designed and synthesized. The cross-conjugated (AM 1 –AM 3 ) and linear-conjugated (AM 5 –AM 7 ) porphyrins displayed strikingly different sets of optical and electronic properties, both of which are unusual and nontypical of porphyrins. MCD, DFT, and TDDFT calculations suggest that multiple charge transfer states exist in both π-conjugated systems, which contributes to the complex absorption and MCD spectra of these molecular systems. The general Gouterman’s four-orbital model used to explain porphyrin spectroscopy led to contradicting theoretical and experimental data, and is thus not applicable for these molecular systems. The “2 + 4” and “3 + 3” active spaces have been deduced and have proven effective to interpret the absorption and MCD spectra of the pentacenequinone-fused (cross-conjugated) and pentacene-fused (linear-conjugated) porphyrins, respectively. Spectroelectrochemistry of AM 5 –AM 7 revealed broad and intense IR absorptions in the range of 1500–2500 nm, illustrating the exceptional ability of these pentacene-fused systems to accommodate positive charges. A pronounced metal effect was observed for pentacene-fused porphyrins. While pentacene-fused Ni­(II) porphyrin (AM6 ) demonstrated an abnormal ability to stabilize pentacene with a half-life of >28.3 days, the half-life of the free base and Zn­(II) counterparts were normal, similar to those of pentacene analogues. This work provides important and useful information on guiding new material designs.