Journal of Porphyrins and Phthalocyanines J. Porphyrins Phthalocyanines 2011; 15: 1150–1171 DOI: 10.1142/S1088424611004221 Published at http://www.worldscinet.com/jpp/ Copyright © 2011 World Scientific Publishing Company Bis- and trisporphyrin bio-inspired models for bacterial antennas and photosystems Pierre D. Harvey* a , Mikhail A. Filatov b† and Roger Guilard* b a Départment de Chimie, Université de Sherbrooke, Sherbrooke, PQ, J1K 2R1, Canada b Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB, UMR 5260 CNRS), Université de Bourgogne, BP 47870-21078, Dijon, France Dedicated to Professor Karl M. Kadish on the occasion of his 65 th birthday Received 29 August 2011 Accepted 28 September 2011 ABSTRACT: This review presents the synthetic aspects and photophysical properties of trimeric systems constructed with a first unit consisting of a cofacial porphyrin and then of another porphyrin attached as a side arm. Two scenarios are dealt with. The first one is the case where the three chromophores are different, called donor 1–donor 2–acceptor, specifically where the cofacial fragment is composed of donor 1 and donor 2, and the side arm is the acceptor. They are considered as models for the apo- proteins used in the LH II (light harvesting device) in the purple photosynthetic bacteria. The second one is the case where the chromophores of the cofacial bisporphyrin residue are identical and are closely placed to each other for inter-ring π-interactions. The side arm is simply a mono-porphyrin, and therefore it is different. The cofacial bisporphyrin unit exhibits then similar characteristics to the special pairs located within the reaction center protein, and are designated as artificial special pairs. On the synthetic standpoint, the various pathways to access such models are presented fully exploiting the Suzuki methodology. On the photophysical side, a large emphasis will be placed on the singlet energy transfers. Cascade processes in the trimers donor 1–donor 2–acceptor are presented and each individual contributions donor 1 → donor 2; donor 2 → acceptor; donor 1 → acceptor are addressed qualitatively and quantitatively. For the artificial special pairs flanked with an antenna, the effect of the spacer between the artificial special pair and the antenna will be discussed as well as the choice of substituents and metal demonstrating that one can reverse the orientation of the singlet energy transfer: artificial special pair → side arm or side arm → artificial special pair. Finally, the antenna effect are presented for one example of artificial special pair equipped with 6 semi-flexible dendritic antennas. KEYWORDS: photosynthetic purple bacteria, light-harvesting complex, photoinduced electron- transfer, singlet state energy-transfer, excited-state dynamics, luminescence properties, porphyrin arrays, cofacial bisporphyrins, Suzuki reaction.  SPP full member in good standing *Correspondence to: Pierre D. Harvey, email: pierre.harvey@ usherbrooke.ca, tel: +1 (819)-821-7092, fax: +1 (819)-821- 8017 and Roger Guilard, email: roger.guilard@u-bourgogne.fr, tel: +33 (0)380-39-61-11, fax: +33 (0)380-39-61-17 † Current address: Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany