@article{kirmaier_song_yang_schwartz_hindin_diers_loewe_tomizaki_chevalier_ramos_et al._2010, title={Excited-State Photodynamics of Perylene-Porphyrin Dyads 5 Tuning Light-Harvesting Characteristics via Perylene Substituents, Connection Motif, and Three-Dimensional Architecture}, volume={114}, ISSN={["1520-5207"]}, DOI={10.1021/jp910705q}, abstractNote={Seven perylene-porphyrin dyads were examined with the goal of identifying those most suitable for components of light-harvesting systems. The ideal dyad should exhibit strong absorption by the perylene in the green, undergo rapid and efficient excited-state energy transfer from perylene to porphyrin, and avoid electron-transfer quenching of the porphyrin excited state by the perylene in the medium of interest. Four dyads have different perylenes at the p-position of the meso-aryl group on the zinc porphyrin. The most suitable perylene identified in that set was then incorporated at the m- or o-position of the zinc porphyrin, affording two other dyads. An analogue of the o-substituted architecture was prepared in which the zinc porphyrin was replaced with the free base porphyrin. The perylene in each dyad is a monoimide derivative; the perylenes differ in attachment of the linker (either via a diphenylethyne linker at the N-imide or an ethynylphenyl linker at the C9 position) and the number (0-3) of 4-tert-butylphenoxy groups (which increase solubility and slightly alter the electrochemical potentials). In the p-linked dyad, the monophenoxy perylene with an N-imide diphenylethyne linker is superior in providing rapid and essentially quantitative energy transfer from excited perylene to zinc porphyrin with minimal electron-transfer quenching in both toluene and benzonitrile. The dyads with the same perylene at the m- or o-position exhibited similar results except for one case, the o-linked dyad bearing the zinc porphyrin in benzonitrile, where significant excited-state quenching is observed; this phenomenon is facilitated by close spatial approach of the perylene and porphyrin and the associated thermodynamic/kinetic enhancement of the electron-transfer process. Such quenching does not occur with the free base porphyrin because electron transfer is thermodynamically unfavorable even in the polar medium. The p-linked dyad containing a zinc porphyrin attached to a bis(4-tert-butylphenoxy)perylene via an ethynylphenyl linker at the C9 position exhibits ultrafast and quantitative energy transfer in toluene; the same dyad in benzonitrile exhibits ultrafast (<0.5 ps) perylene-to-porphyrin energy transfer, rapid (∼5 ps) porphyrin-to-perylene electron transfer, and fast (∼25 ps) charge recombination to the ground state. Collectively, this study has identified suitable perylene-porphyrin constructs for use in light-harvesting applications.}, number={45}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, author={Kirmaier, Christine and Song, Hee-eun and Yang, Eunkyung and Schwartz, Jennifer K. and Hindin, Eve and Diers, James R. and Loewe, Robert S. and Tomizaki, Kin-ya and Chevalier, Fabien and Ramos, Lavoisier and et al.}, year={2010}, month={Nov}, pages={14249–14264} }
 @misc{loewe_tomizaki_lindsey_2005, title={Synthesis of perylene-porphyrin building blocks and polymers thereof for the production of light-harvesting arrays}, volume={6,916,982}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Loewe, R. S. and Tomizaki, K.-Y. and Lindsey, J. S.}, year={2005} }
 @article{hindin_kirmaier_diers_tomizaki_taniguchi_lindsey_bocian_holten_2004, title={Photophysical properties of phenylethyne-linked porphyrin and oxochlorin dyads}, volume={108}, ISSN={["1520-6106"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-3042636305&partnerID=MN8TOARS}, DOI={10.1021/jp037614l}, abstractNote={A set of porphyrin-porphyrin and oxochlorin-oxochlorin dyads has been prepared in which the constituent pigments are joined at the meso-positions by a phenylethyne linker. Attachment of an ethynyl substituent to the meso-position of a tetrapyrrolic macrocycle strongly perturbs the electronic properties of the ring. The inherent asymmetry of the phenylethyne linker affords the possibility of perturbing either end of the dyad. The porphyrin dyads include bis-Zn, Zn-free base (Fb), and bis-Zn species wherein 0, 1, or 2 of the three nonlinking aryl rings of one of the Zn porphyrins are perfluorinated. The two oxochlorin dyads are both ZnFb species in which the meso-ethyne substituent is located on either the Zn complex or the Fb. The dyads have been studied using static and time-resolved absorption and emission spectroscopy and electrochemical techniques. The optical and electrochemical properties of a series of monomeric reference compounds were also examined. The time-resolved optical studies reveal that energy transfer in the phenylethyne-linked dyads is faster by ∼10-fold or more than in analogous dyads joined by a diphenylethyne linker. In particular, energy transfer occurs with a rate constant of > (20 ps) - 1 between the phenylethyne-linked oxochlorins and an efficiency of >98%, to be compared with a rate of (140 ps) - 1 and an efficiency of 83% found previously for diphenylethyne-linked oxochlorins. Taken together, these results should be useful in the design of multipigment architectures that absorb in the red and undergo fast and efficient energy transfer, as required for light-harvesting applications.}, number={24}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, publisher={American Chemical Society (ACS)}, author={Hindin, E and Kirmaier, C and Diers, JR and Tomizaki, KY and Taniguchi, M and Lindsey, JS and Bocian, DF and Holten, D}, year={2004}, month={Jun}, pages={8190–8200} }
 @article{tomizaki_lysenko_taniguchi_lindsey_2004, title={Synthesis of phenylethyne-linked porphyrin dyads}, volume={60}, ISSN={["0040-4020"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-1042275557&partnerID=MN8TOARS}, DOI={10.1016/j.tet.2004.01.003}, abstractNote={Four new porphyrin dyads have been prepared for studies in artificial photosynthesis. The two porphyrins are joined at the meso positions via a phenylethyne linker and are present in zinc/zinc or zinc/free base metalation states. The porphyrin bearing the ethynyl unit incorporates zero, one, or two pentafluorophenyl groups at non-linking meso positions for tuning the porphyrin redox potentials. The synthetic approach entailed Pd-mediated coupling of porphyrin building blocks that bear a single ethynylphenyl or bromo/iodo substituent.}, number={9}, journal={TETRAHEDRON}, publisher={Elsevier BV}, author={Tomizaki, K and Lysenko, AB and Taniguchi, M and Lindsey, JS}, year={2004}, month={Feb}, pages={2011–2023} }
 @article{tomizaki_yu_wei_bocian_lindsey_2003, title={Synthesis of cyclic hexameric porphyrin arrays. Anchors for surface immobilization and columnar self-assembly}, volume={68}, ISSN={["1520-6904"]}, DOI={10.1021/jo034861c}, abstractNote={To investigate new architectures for the self-assembly of multiporphyrin arrays, a one-flask synthesis of a shape-persistent cyclic hexameric array of porphyrins was exploited to prepare six derivatives bearing diverse pendant groups. The new arrays contain 6-12 carboxylic acid groups, 12 amidino groups, 6 thiol groups, or 6 thiol groups and 6 carboxylic acid groups in protected form (S-acetylthio, TMS-ethyl, TMS-ethoxycarbonyl). The arrays contain alternating Zn and free base (Fb) porphyrins or all Zn porphyrins. The one-flask synthesis entails a template-directed, Pd-mediated coupling of a p/p'-substituted diethynyl Zn porphyrin and a m/m'-substituted diiodo Fb porphyrin. The porphyrin building blocks (trans-A(2)B(2), trans-AB(2)C) contain the protected pendant groups at nonlinking meso positions. A self-assembled monolayer (SAM) of a Zn(3)Fb(3) cyclic hexamer containing one thiol group on each porphyrin was prepared on a gold electrode and the surface-immobilized architecture was examined electrochemically. Together, the work reported herein provides cyclic hexameric porphyrin arrays for studies of self-assembly in solution or on surfaces.}, number={21}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Tomizaki, KY and Yu, LH and Wei, LY and Bocian, DF and Lindsey, JS}, year={2003}, month={Oct}, pages={8199–8207} }
 @article{tomizaki_loewe_kirmaier_schwartz_retsek_bocian_holten_lindsey_2002, title={Synthesis and photophysical properties of light-harvesting arrays comprised of a porphyrin bearing multiple perylene-monoimide accessory pigments}, volume={67}, ISSN={["1520-6904"]}, DOI={10.1021/jo0258002}, abstractNote={We present the synthesis and characterization of new light-harvesting arrays containing two, four, or eight perylene-monoimide accessory pigments attached to a zinc porphyrin. Each perylene is substituted with one or three 4-tert-butylphenoxy substituents. A 4,3'- or 4,2'-diarylethyne linker joins the perylene N-imide position and the porphyrin meso-position, affording divergent or convergent architectures, respectively. The architectures are designed to provide high solubility in organic media and facile perylene-to-porphyrin energy transfer, while avoiding charge-transfer quenching of the excited porphyrin product. For the array containing four perylenes per porphyrin in both nonpolar (toluene) and polar (benzonitrile) media and for the array containing eight perylenes per porphyrin in toluene, the photoexcited perylene-monoimide dye (PMI) decays rapidly ( approximately 3.5 ps) and predominantly (>or=90%) by energy transfer to the zinc porphyrin to form the excited zinc porphyrin (Zn), which has excited-state characteristics (lifetime, fluorescence yield) comparable (within approximately 10%) to those of the isolated chromophore. For the array containing eight perylenes in benzonitrile, PMI decays approximately 80% by energy transfer (forming Zn) and approximately 20% by hole transfer (forming PMI- Zn+); Zn subsequently decays approximately 20% by electron transfer (also forming PMI- Zn+) and approximately 80% by the normal routes open to the porphyrin monomer (intersystem crossing, internal conversion, fluorescence). In addition to rapid and efficient perylene-to-porphyrin energy transfer, the broad blue-green to yellow absorption of the perylene dyes complements the blue absorption of the porphyrin, resulting in excellent light harvesting across a significant spectral region. Collectively, the work described herein identifies multiperylene-porphyrin arrays that exhibit suitable photochemical properties for use as motifs in larger light-harvesting systems.}, number={18}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Tomizaki, K and Loewe, RS and Kirmaier, C and Schwartz, JK and Retsek, JL and Bocian, DF and Holten, D and Lindsey, JS}, year={2002}, month={Sep}, pages={6519–6534} }
 @article{loewe_tomizaki_youngblood_bo_lindsey_2002, title={Synthesis of perylene-porphyrin building blocks and rod-like oligomers for light-harvesting applications}, volume={12}, ISSN={["1364-5501"]}, DOI={10.1039/b205680a}, abstractNote={We present the synthesis of four perylene–porphyrin building blocks for use in Glaser, Sonogashira, or Suzuki polymerizations. The building blocks bear synthetic handles (4-ethynylphenyl, 4-iodophenyl, bromo) at the trans 
(5,15) 
meso-positions of a zinc porphyrin and contain two or four perylene-monoimide dyes attached at the 3,5-positions of the non-linking meso-aryl rings of the porphyrin. Each perylene-monoimide bears three 4-tert-butylphenoxy substituents (at the 1-, 6-, and 9-positions) and two isopropyl groups (on the N-aryl unit) for increased solubility. In each case the intervening linker is a diarylethyne unit that bridges the N-imide position of the perylene and the meso-position of the porphyrin. The perylene–porphyrin building blocks were prepared by (1) reaction of a diperylene-dipyrromethane with an aldehyde yielding a trans-A2B2-porphyrin, (2) reaction of a diperylene-aldehyde with a dipyrromethane yielding a trans-A2B2-porphyrin, and (3) reaction of a diperylene-dipyrromethane with a dipyrromethane-dicarbinol yielding a trans-AB2C-porphyrin or ABCD-porphyrin. The building blocks were subjected to Glaser, Sonogashira, or Suzuki coupling conditions in an effort to prepare oligomers containing porphyrins joined via 4,4′-diphenylbutadiyne (dpb), 4,4′-diphenylethyne (dpe), or 1,4-phenylene linkers (p), respectively. Each porphyrin in the backbone bears two or four pendant perylene-monoimide dyes. The Glaser and Sonogashira reactions afforded a distribution of oligomers, whereas the Suzuki reaction was unsuccessful. The oligomers were soluble in solvents such as toluene, THF, or CHCl3 enabling routine handling. The use of perylenes results in (1) increased light-harvesting efficiency particularly in the green spectral region where porphyrins are relatively transparent and (2) greater solubility than is achieved with the use of porphyrins alone. The soluble perylene–porphyrin oligomers are attractive for use as light-harvesting materials in molecular-based solar cells.}, number={12}, journal={JOURNAL OF MATERIALS CHEMISTRY}, author={Loewe, RS and Tomizaki, K and Youngblood, WJ and Bo, ZS and Lindsey, JS}, year={2002}, pages={3438–3451} }
 @article{loewe_tomizaki_chevalier_lindsey_2002, title={Synthesis of perylene-porphyrin dyads for light-harvesting studies}, volume={6}, ISSN={["1099-1409"]}, DOI={10.1142/S1088424602000774}, abstractNote={ The spectral coverage of porphyrin-based light-harvesting arrays can be enhanced through the use of suitable accessory pigments. Perylene-monoimide dyes can serve as valuable accessory pigments with porphyrins. To investigate the choice of perylene-monoimide and the effects of molecular architecture on light-harvesting efficacy, five perylene-porphyrin dyads were prepared. Each dyad employs a diphenylethyne linker that bridges the perylene N-imide site and the porphyrin meso-position. Three dyads incorporate a mono-phenoxy perylene at the o-, m-, or p-position of the meso-aryl group on the porphyrin. The two remaining dyads incorporate a perylene-monoimide (bearing zero or three phenoxy substituents) at the p-position of the meso-aryl group on the porphyrin. The introduction of phenoxy groups on the perylenes increases the solubility, a key requirement for use in light-harvesting arrays. The long-wavelength absorption band of the perylene shifts from 506 nm to 532 or 533 nm upon substitution with one or three phenoxy groups, respectively. The synthesis of the dyads entails Pd -mediated coupling of a bromo-perylene and an ethynyl porphyrin, or the mixed-aldehyde condensation with a perylene-aldehyde, mesitaldehyde, and pyrrole. Five perylene-monoimide dyes bearing an ethyne or bromo substituent at the p-position of the N-aryl unit were developed for this modular chemistry. Each perylene-porphyrin dyad exhibits efficient energy transfer from the excited perylene to the ground-state porphyrin. }, number={9-10}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, author={Loewe, RS and Tomizaki, KY and Chevalier, F and Lindsey, JS}, year={2002}, pages={626–642} }