@misc{lindsey_chinnasamy_fan_2009, title={Self-assembled photosynthesis-inspired light harvesting material and solar cells containing the same}, volume={7,633,007}, number={1999 Dec. 15}, author={Lindsey, J. S. and Chinnasamy, M. and Fan, D.}, year={2009} } @article{stromberg_marton_kee_kirmaier_diers_muthiah_taniguchi_lindsey_bocian_meyer_et al._2007, title={Examination of tethered porphyrin, chlorin, and bacteriochlorin molecules in mesoporous metal-oxide solar cells}, volume={111}, ISSN={["1932-7447"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-35748969147&partnerID=MN8TOARS}, DOI={10.1021/jp0749928}, abstractNote={The performance of five tetrapyrrole molecules as sensitizers in regenerative solar cells was evaluated. The tetrapyrroles form two sets. One set contains three meso-substituted porphyrins that differ only in the nature of their surface-binding tether:  isophthalic acid, ethynylisophthalic acid, or cyanoacrylic acid. The other set includes the ethynylisophthalic acid tether attached to porphyrin, chlorin, and bacteriochlorin macrocycles, which contain zero, one, and two saturated pyrrole rings, respectively. Incident photon-to-current efficiency was measured for each sensitizer loaded onto a mesoporous TiO2 semitransparent electrode in a solar cell. The porphyrin bearing the cyanoacrylic acid tether gives the largest peak and integrated (350−900 nm) photocurrent density of the five tetrapyrrole molecules. For this sensitizer, a quasi-monochromatic power conversion efficiency of 21% was obtained at the Soret maximum (450 nm), along with a fill factor of 0.69. To elucidate the molecular origins of the effec...}, number={42}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, publisher={American Chemical Society (ACS)}, author={Stromberg, Jonathan R. and Marton, Andras and Kee, Hooi Ling and Kirmaier, Christine and Diers, James R. and Muthiah, Chinnasamy and Taniguchi, Masahiko and Lindsey, Jonathan S. and Bocian, David F. and Meyer, Gerald J. and et al.}, year={2007}, month={Oct}, pages={15464–15478} } @article{muthiah_bhaumik_lindsey_2007, title={Rational routes to formyl-substituted chlorins}, volume={72}, ISSN={["0022-3263"]}, DOI={10.1021/jo0707885}, abstractNote={Two distinct approaches have been developed for the synthesis of chlorins bearing formyl groups: (1) reaction of an acetal-substituted 1-acyldipyrromethane with 2,3,5,6-tetrahydro-1,3,3-trimethyldipyrrin to give upon hydrolysis a 5-formylchlorin and (2) Pd-mediated coupling of a bromochlorin with a one-carbon synthon (hydroxymethyl tributyltin or CO) to give a 13-, 15-, or 3,13-formylchlorin. The zinc chlorins exhibit long-wavelength peak absorption maxima ranging from 626 to 667 nm, indicating the wavelength tunability afforded by formyl substitution.}, number={15}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Muthiah, Chinnasamy and Bhaumik, Jayeeta and Lindsey, Jonathan S.}, year={2007}, month={Jul}, pages={5839–5842} } @article{muthiah_ptaszek_nguyen_flack_lindsey_2007, title={Two complementary routes to 7-substituted chlorins. Partial mimics of chlorophyll b}, volume={72}, ISSN={["1520-6904"]}, DOI={10.1021/jo701500d}, abstractNote={Chlorophyll a and chlorophyll b exhibit distinct spectra yet differ only in the nature of a single substituent (7-methyl versus 7-formyl, respectively). Two complementary approaches have been developed for the synthesis of 7-substituted chlorins. The first approach is a de novo route wherein 2,9-dibromo-5-p-tolyldipyrromethane (Eastern half) and 9-formyl-2,3,4,5-tetrahydro-1,3,3-trimethyldipyrrin (Western half) undergo acid-catalyzed condensation followed by metal-mediated oxidative cyclization. The resulting zinc chlorin is sterically uncongested and bears (1) a geminal dimethyl group in the reduced, pyrroline ring, (2) a bromo substituent at the 7-position, and (3) a p-tolyl group at the 10-position. The second approach entails regioselective 7-bromination of a 10,15-diarylchlorin that lacks a substituent at the 5-position. In an extension of this latter approach, a 5,15-diarylchlorin that lacks a substituent at the 10-position undergoes regioselective bromination at the 8-position. The introduction of a TIPS-ethynyl, acetyl, or formyl group at the 7-position was achieved using Pd-catalyzed reactions with the corresponding 7-bromochlorin. In the 10-p-tolyl-substituted zinc chlorins, the series of substituents (7-TIPS-ethynyl, 7-acetyl, 7-formyl) progressively causes (1) a bathochromic shift in the absorption maximum of the B band (405 to 426 nm) and (2) a hypsochromic shift in the position of the Qy band (605 to 598 nm). The trends mirror those for chlorophyll b versus chlorophyll a but are of lesser magnitude. Taken together, the facile access to chlorins that bear auxochromes at the 7-position enables wavelength tunability and provides the foundation for fundamental spectroscopic studies.}, number={20}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Muthiah, Chinnasamy and Ptaszek, Marcin and Nguyen, Tien M. and Flack, Kyle M. and Lindsey, Jonathan S.}, year={2007}, month={Sep}, pages={7736–7749} } @article{laha_muthiah_taniguchi_mcdowell_ptaszek_lindsey_2006, title={Synthetic chlorins bearing auxochromes at the 3- and 13-positions}, volume={71}, ISSN={["0022-3263"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33646926396&partnerID=MN8TOARS}, DOI={10.1021/jo060208o}, abstractNote={Synthetic chlorins bearing diverse auxochromes at the 3- and 13-positions of the macrocycle are valuable targets given their resemblance to chlorophylls a and b, which bear 3-vinyl and 13-keto groups. A de novo route has been exploited to construct nine zinc chlorins bearing substituents at the 3- and 13-positions and two benchmark zinc chlorins lacking such substituents. The chlorins are sterically uncongested and bear (1) a geminal dimethyl group in the reduced pyrroline ring, (2) a H, an acetyl, a triisopropylsilylethynyl (TIPS-ethynyl), or a vinyl at the 3-position, (3) a H, an acetyl, or TIPS-ethynyl at the 13-position, and (4) a H or a mesityl at the 10-position. The synthesis of the 13-substituted chlorins relied on p-TsOH x H2O-catalyzed condensation of an 8,9-dibromo-1-formyldipyrromethane (eastern half) and 2,3,4,5-tetrahydro-1,3,3-trimethyldipyrrin (western half), followed by metal-mediated oxidative cyclization, affording the 13-bromochlorin. Similar use of a bromo- or TIPS-ethynyl-substituted western half provided access to 3-substituted chlorins. A 3-bromo, 13-bromo, or 3,13-dibromochlorin was further transformed by Pd-coupling to introduce the vinyl group (via tributylvinyltin), TIPS-ethynyl group (via TIPS-acetylene), or acetyl group (via tributyl(1-ethoxyvinyl)tin, followed by acidic hydrolysis). In the 10-mesityl-substituted zinc chlorins, the series of substituents, 3-vinyl, 13-TIPS-ethynyl, 3-TIPS-ethynyl, 13-acetyl, 3,13-bis(TIPS-ethynyl), 3-TIPS-ethynyl-13-acetyl, or 3,13-diacetyl, progressively causes (1) a redshift in the absorption maximum of the B band (405-436 nm) and the Q(y) band (606-662 nm), (2) a relative increase in the intensity of the Q(y) band (I(B)/I(Q) = 4.2-1.5), and (3) an increase in the fluorescence quantum yield phi(f) (0.059-0.29). The zinc chlorins bearing a 3-TIPS-ethynyl-13-acetyl or a 3,13-diacetyl group exhibit a number of spectral properties resembling those of chlorophyll a or its zinc analogue. Taken together, this study provides access to finely tuned chlorins for spectroscopic studies and diverse applications.}, number={11}, journal={JOURNAL OF ORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Laha, Joydev K. and Muthiah, Chinnasamy and Taniguchi, Masahiko and McDowell, Brian E. and Ptaszek, Marcin and Lindsey, Jonathan S.}, year={2006}, month={May}, pages={4092–4102} }