@article{fujita_jing_krayer_allu_veeraraghavaiah_wu_jiang_diers_magdaong_mandal_et al._2019, title={Annulated bacteriochlorins for near- infrared photophysical studies}, volume={43}, ISSN={["1369-9261"]}, DOI={10.1039/c9nj01113g}, abstractNote={Bacteriochlorins with phenaleno or benzo annulation absorb at 913 or 1033 nm and exhibit excited-state lifetimes of 150 or 7 ps, suggesting applications in photoacoustic imaging.}, number={19}, journal={NEW JOURNAL OF CHEMISTRY}, author={Fujita, Hikaru and Jing, Haoyu and Krayer, Michael and Allu, Srinivasarao and Veeraraghavaiah, Gorre and Wu, Zhiyuan and Jiang, Jianbing and Diers, James R. and Magdaong, Nikki Cecil M. and Mandal, Amit K. and et al.}, year={2019}, month={May}, pages={7209–7232} }
 @article{vairaprakash_yang_sahin_taniguchi_krayer_diers_wang_niedzwiedzki_kirmaier_lindsey_et al._2015, title={Extending the Short and Long Wavelength Limits of Bacteriochlorin Near-Infrared Absorption via Dioxo- and Bisimide-Functionalization}, volume={119}, ISSN={["1520-6106"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84925935682&partnerID=MN8TOARS}, DOI={10.1021/jp512818g}, abstractNote={Six new bacteriochlorins expanding the range of the strong near-infrared (NIR) absorption (Qy band) to both shorter and longer wavelengths (∼690 to ∼900 nm) have been synthesized and characterized. The architectures include bacteriochlorin–bisimides that have six-membered imide rings spanning the 3,5- and 13,15-macrocycle positions or five-membered imide rings spanning the β-pyrrolic 2,3- and 12,13-positions. Both bisimide types absorb at significantly longer wavelength than the bacteriochlorin precursors (no fused rings), whereas oxo-groups at the 7- or 7,17-positions shift the Qy band to a new short wavelength limit. Surprisingly, bacteriochlorin–bisimides with five-membered β-pyrrolic-centered imide rings have a Qy band closer to that of six-membered bacteriochlorin–monoimides. However, the five-membered bisimides (versus the six-membered bacteriochlorin–monoimides) have significantly enhanced absorption intensity that is paralleled by an ∼2-fold higher fluorescence yield (∼0.16 vs ∼0.07) and longer singlet excited-state lifetime (∼4 ns vs ∼2 ns). The photophysical enhancements derive in part from mixing of the lowest unoccupied frontier molecular orbitals of the five-membered imide ring with those of the bacteriochlorin framework. In general, all of the new bacteriochlorins have excited-state lifetimes (1–4 ns) that are sufficiently long for use in molecular-based systems for photochemical applications.}, number={12}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, author={Vairaprakash, Pothiappan and Yang, Eunkyung and Sahin, Tuba and Taniguchi, Masahiko and Krayer, Michael and Diers, James R. and Wang, Alfred and Niedzwiedzki, Dariusz M. and Kirmaier, Christine and Lindsey, Jonathan S. and et al.}, year={2015}, month={Mar}, pages={4382–4395} }
 @article{faries_diers_springer_yang_ptaszek_lahaye_krayer_taniguchi_kirmaier_lindsey_et al._2015, title={Photophysical Properties and Electronic Structure of Chlorin-Imides: Bridging the Gap between Chlorins and Bacteriochlorins}, volume={119}, ISSN={["1520-5207"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84934319596&partnerID=MN8TOARS}, DOI={10.1021/jp511257w}, abstractNote={Efficient light harvesting for molecular-based solar-conversion systems requires absorbers that span the photon-rich red and near-infrared (NIR) regions of the solar spectrum. Reported herein are the photophysical properties of a set of six chlorin-imides and nine synthetic chlorin analogues that extend the absorption deeper (624-714 nm) into these key spectral regions. These absorbers help bridge the gap between typical chlorins and bacteriochlorins. The new compounds have high fluorescence quantum yields (0.15-0.34) and long singlet excited-state lifetimes (4.2-10.9 ns). The bathochromic shift in Qy absorption is driven by substituent-based stabilization of the lowest unoccupied molecular orbital, with the largest shifts for chlorins that bear an electron-withdrawing, conjugative group at the 3-position in combination with a 13,15-imide ring.}, number={24}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, author={Faries, Kaitlm M. and Diers, James R. and Springer, Joseph W. and Yang, Eunkyung and Ptaszek, Marcin and Lahaye, Dorothee and Krayer, Michael and Taniguchi, Masahiko and Kirmaier, Christine and Lindsey, Jonathan S. and et al.}, year={2015}, month={Jun}, pages={7503–7515} }
 @article{springer_taniguchi_krayer_ruzie_diers_niedzwiedzki_bocian_lindsey_holten_2014, title={Photophysical properties and electronic structure of retinylidene-chlorin-chalcones and analogues}, volume={13}, number={4}, journal={Photochemical & Photobiological Sciences}, author={Springer, J. W. and Taniguchi, M. and Krayer, M. and Ruzie, C. and Diers, J. R. and Niedzwiedzki, D. M. and Bocian, D. F. and Lindsey, J. S. and Holten, D.}, year={2014}, pages={634–650} }
 @article{huang_krayer_roubil_huang_holten_lindsey_hamblin_2014, title={Stable synthetic mono-substituted cationic bacteriochlorins mediate selective broad-spectrum photoinactivation of drug-resistant pathogens at nanomolar concentrations}, volume={141}, ISSN={["1873-2682"]}, DOI={10.1016/j.jphotobiol.2014.09.016}, abstractNote={Three stable synthetic mono-substituted cationic bacteriochlorins (BC37, BC38 and BC39) were recently reported to show exceptional activity (low nanomolar) in mediating photodynamic killing of human cancer cells after a 24h incubation upon excitation with near-infrared light (730 nm). The presence of cationic quaternary ammonium groups in each compound suggested likely activity as antimicrobial photosensitizers. Herein this hypothesis was tested against a panel of pathogenic microorganisms that have all recently drawn attention due to increased drug-resistance (Gram-positive bacteria, Staphylococcus aureus and Enterococcus faecalis; Gram-negative bacteria, Escherichia coli and Acinetobacter baumannii; and fungal yeasts, Candida albicans and Cryptococcus neoformans). All three bacteriochlorins were highly effective against both Gram-positive species (>6 logs of eradication at ⩽ 200 nM and 10 J/cm(2)). The dicationic bacteriochlorin (BC38) was best against the Gram-negative species (>6 logs at 1-2 μM) whereas the lipophilic monocationic bacteriochlorin (BC39) was best against the fungi (>6 logs at 1 μM). The bacteriochlorins produced substantial singlet oxygen (and apparently less Type-1 reactive-oxygen species such as hydroxyl radical) as judged by activation of fluorescent probes and comparison with 1H-phenalen-1-one-2-sulfonic acid; the order of activity was BC37 > BC38 > BC39. A short incubation time (30 min) resulted in selectivity for microbial cells over HeLa human cells. The highly active photodynamic inactivation of microbial cells may stem from the amphiphilic and cationic features of the bacteriochlorins.}, journal={JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY}, author={Huang, Liyi and Krayer, Michael and Roubil, John G. S. and Huang, Ying-Ying and Holten, Dewey and Lindsey, Jonathan S. and Hamblin, Michael R.}, year={2014}, month={Dec}, pages={119–127} }
 @article{reddy_jiang_krayer_harris_springer_yang_jiao_niedzwiedzki_pandithavidana_parkes-loach_et al._2013, title={Palette of lipophilic bioconjugatable bacteriochlorins for construction of biohybrid light-harvesting architectures}, volume={4}, number={5}, journal={Chemical Science}, author={Reddy, K. R. and Jiang, J. B. and Krayer, M. and Harris, M. A. and Springer, J. W. and Yang, E. and Jiao, J. Y. and Niedzwiedzki, D. M. and Pandithavidana, D. and Parkes-Loach, P. S. and et al.}, year={2013}, pages={2036–2053} }
 @article{yang_ruzie_krayer_diers_niedzwiedzki_kirmaier_lindsey_bocian_holten_2013, title={Photophysical Properties and Electronic Structure of Bacteriochlorin-Chalcones with Extended Near-Infrared Absorption}, volume={89}, ISSN={["1751-1097"]}, DOI={10.1111/php.12053}, abstractNote={Synthetic bacteriochlorins enable systematic tailoring of substituents about the bacteriochlorin chromophore and thereby provide insights concerning the native bacteriochlorophylls of bacterial photosynthesis. Nine free-base bacteriochlorins (eight prepared previously and one prepared here) have been examined that bear diverse substituents at the 13- or 3,13-positions. The substituents include chalcone (3-phenylprop-2-en-1-onyl) derivatives with groups attached to the phenyl moiety, a "reverse chalcone" (3-phenyl-3-oxo-1-enyl), and extended chalcones (5-phenylpenta-2,4-dien-1-onyl, retinylidenonyl). The spectral and photophysical properties (τs, Φf, Φ(ic), Φ(isc), τT, k(f), k(ic), k(isc)) of the bacteriochlorins have been characterized. The bacteriochlorins absorb strongly in the 780-800 nm region and have fluorescence quantum yields (Φf) in the range 0.05-0.11 in toluene and dimethylsulfoxide. Light-induced electron promotions between orbitals with predominantly substituent or macrocycle character or both may give rise to some net macrocycle ↔ substituent charge-transfer character in the lowest and higher singlet excited states as indicated by density functional theory (DFT) and time-dependent DFT calculations. Such calculations indicated significant participation of molecular orbitals beyond those (HOMO - 1 to LUMO + 1) in the Gouterman four-orbital model. Taken together, the studies provide insight into the fundamental properties of bacteriochlorins and illustrate designs for tuning the spectral and photophysical features of these near-infrared-absorbing tetrapyrrole chromophores.}, number={3}, journal={PHOTOCHEMISTRY AND PHOTOBIOLOGY}, author={Yang, Eunkyung and Ruzie, Christian and Krayer, Michael and Diers, James R. and Niedzwiedzki, Dariusz M. and Kirmaier, Christine and Lindsey, Jonathan S. and Bocian, David F. and Holten, Dewey}, year={2013}, pages={586–604} }
 @article{sharma_krayer_sperandio_huang_huang_holten_lindsey_hamblin_2013, title={Synthesis and evaluation of cationic bacteriochlorin amphiphiles with effective in vitro photodynamic activity against cancer cells at low nanomolar concentration}, volume={17}, ISSN={["1099-1409"]}, DOI={10.1142/s108842461250126x}, abstractNote={Bacteriochlorins are attractive candidates as photosensitizers for photodynamic therapy (PDT) due to their intense absorption in the near-infrared (NIR) region of the spectrum where light transmission through tissue is maximal. Many naturally occurring bacteriochlorins are inherently unstable due to adventitious atmospheric oxidation. A de novo synthesis affords bacteriochlorins that contain a geminal dimethyl group in each reduced pyrrole ring to increase stability against oxidation. Here, three new synthetic bacteriochlorins, each bearing a single side-chain containing one or two positive charges, were investigated for their in vitro PDT activity against HeLa human cancer cells. All bacteriochlorins were active at low nanomolar concentration when activated with NIR light; those bearing a single positive charge exhibited faster uptake and higher activity. The bacteriochlorins were localized in mitochondria, lysosomes and endoplasmic reticulum as shown by organelle specific fluorescent probes. Cell death was via apoptosis as shown by cell morphology and nuclear condensation. Taken together, the results show the importance of appropriate peripheral groups about a photosensitizer for effective PDT applications.}, number={1-2}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, author={Sharma, Sulbha K. and Krayer, Michael and Sperandio, Felipe F. and Huang, Liyi and Huang, Ying-Ying and Holten, Dewey and Lindsey, Jonathan S. and Hamblin, Michael R.}, year={2013}, pages={73–85} }
 @article{springer_parkes-loach_reddy_krayer_jiao_lee_niedzwiedzki_harris_kirmaier_bocian_et al._2012, title={Biohybrid Photosynthetic Antenna Complexes for Enhanced Light-Harvesting}, volume={134}, ISSN={["1520-5126"]}, DOI={10.1021/ja207390y}, abstractNote={Biohybrid antenna systems have been constructed that contain synthetic chromophores attached to 31mer analogues of the bacterial photosynthetic core light-harvesting (LH1) β-polypeptide. The peptides are engineered with a Cys site for bioconjugation with maleimide-terminated chromophores, which include synthetic bacteriochlorins (BC1, BC2) with strong near-infrared absorption and commercial dyes Oregon green (OGR) and rhodamine red (RR) with strong absorption in the blue-green to yellow-orange regions. The peptides place the Cys 14 (or 6) residues before a native His site that binds bacteriochlorophyll a (BChl-a) and, like the native LH proteins, have high helical content as probed by single-reflection IR spectroscopy. The His residue associates with BChl-a as in the native LH1 β-polypeptide to form dimeric ββ-subunit complexes [31mer(-14Cys)X/BChl](2), where X is one of the synthetic chromophores. The native-like BChl-a dimer has Q(y) absorption at 820 nm and serves as the acceptor for energy from light absorbed by the appended synthetic chromophore. The energy-transfer characteristics of biohybrid complexes have been characterized by steady-state and time-resolved fluorescence and absorption measurements. The quantum yields of energy transfer from a synthetic chromophore located 14 residues from the BChl-coordinating His site are as follows: OGR (0.30) < RR (0.60) < BC2 (0.90). Oligomeric assemblies of the subunit complexes [31mer(-14Cys)X/BChl](n) are accompanied by a bathochromic shift of the Q(y) absorption of the BChl-a oligomer as far as the 850-nm position found in cyclic native photosynthetic LH2 complexes. Room-temperature stabilized oligomeric biohybrids have energy-transfer quantum yields comparable to those of the dimeric subunit complexes as follows: OGR (0.20) < RR (0.80) < BC1 (0.90). Thus, the new biohybrid antennas retain the energy-transfer and self-assembly characteristics of the native antenna complexes, offer enhanced coverage of the solar spectrum, and illustrate a versatile paradigm for the construction of artificial LH systems.}, number={10}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Springer, Joseph W. and Parkes-Loach, Pamela S. and Reddy, Kanumuri Ramesh and Krayer, Michael and Jiao, Jieying and Lee, Gregory M. and Niedzwiedzki, Dariusz M. and Harris, Michelle A. and Kirmaier, Christine and Bocian, David F. and et al.}, year={2012}, month={Mar}, pages={4589–4599} }
 @article{krayer_yang_diers_bocian_holten_lindsey_2011, title={De novo synthesis and photophysical characterization of annulated bacteriochlorins. Mimicking and extending the properties of bacteriochlorophylls}, volume={35}, number={3}, journal={New Journal of Chemistry}, author={Krayer, M. and Yang, E. and Diers, J. R. and Bocian, D. F. and Holten, D. and Lindsey, J. S.}, year={2011}, pages={587–601} }
 @article{aravindu_krayer_kim_lindsey_2011, title={Facile synthesis of a B,D-tetradehydrocorrin and rearrangement to bacteriochlorins}, volume={35}, number={7}, journal={New Journal of Chemistry}, author={Aravindu, K. and Krayer, M. and Kim, H. J. and Lindsey, J. S.}, year={2011}, pages={1376–1384} }
 @article{yang_kirmaier_krayer_taniguchi_kim_diers_bocian_lindsey_holten_2011, title={Photophysical Properties and Electronic Structure of Stable, Tunable Synthetic Bacteriochlorins: Extending the Features of Native Photosynthetic Pigments}, volume={115}, ISSN={["1520-5207"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-80052828697&partnerID=MN8TOARS}, DOI={10.1021/jp205258s}, abstractNote={Bacteriochlorins, which are tetrapyrrole macrocycles with two reduced pyrrole rings, are Nature's near-infrared (NIR) absorbers (700-900 nm). The strong absorption in the NIR region renders bacteriochlorins excellent candidates for a variety of applications including solar light harvesting, flow cytometry, molecular imaging, and photodynamic therapy. Natural bacteriochlorins are inherently unstable due to oxidative conversion to the chlorin (one reduced pyrrole ring) or the porphyrin. The natural pigments are also only modestly amenable to synthetic manipulation, owing to a nearly full complement of substituents on the macrocycle. Recently, a new synthetic methodology has afforded access to stable synthetic bacteriochlorins wherein a wide variety of substituents can be appended to the macrocycle at preselected locations. Herein, the spectroscopic and photophysical properties of 33 synthetic bacteriochlorins are investigated. The NIR absorption bands of the chromophores range from ∼700 to ∼820 nm; the lifetimes of the lowest excited singlet state range from ∼2 to ∼6 ns; the fluorescence quantum yields range from ∼0.05 to ∼0.25; and the yield of the lowest triplet excited state is ∼0.5. The spectroscopic/photophysical studies of the bacteriochlorins are accompanied by density functional theory (DFT) calculations that probe the characteristics of the frontier molecular orbitals. The DFT calculations indicate that the impact of substituents on the spectral properties of the molecules derives primarily from effects on the lowest unoccupied molecular orbital. Collectively, the studies show how the palette of synthetic bacteriochlorins extends the properties of the native photosynthetic pigments (bacteriochlorophylls). The studies have also elucidated design principles for tuning the spectral and photophysical characteristics as required for a wide variety of photochemical applications.}, number={37}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, publisher={American Chemical Society (ACS)}, author={Yang, Eunkyung and Kirmaier, Christine and Krayer, Michael and Taniguchi, Masahiko and Kim, Han-Je and Diers, James R. and Bocian, David F. and Lindsey, Jonathan S. and Holten, Dewey}, year={2011}, month={Sep}, pages={10801–10816} }
 @article{krayer_yang_kim_kee_deans_sluder_diers_kirmaier_bocian_holten_et al._2011, title={Synthesis and Photophysical Characterization of Stable Indium Bacteriochlorins}, volume={50}, ISSN={["1520-510X"]}, DOI={10.1021/ic200325d}, abstractNote={Bacteriochlorins have wide potential in photochemistry because of their strong absorption of near-infrared light, yet metallobacteriochlorins traditionally have been accessed with difficulty. Established acid-catalysis conditions [BF(3)·OEt(2) in CH(3)CN or TMSOTf/2,6-di-tert-butylpyridine in CH(2)Cl(2)] for the self-condensation of dihydrodipyrrin-acetals (bearing a geminal dimethyl group in the pyrroline ring) afford stable free base bacteriochlorins. Here, InBr(3) in CH(3)CN at room temperature was found to give directly the corresponding indium bacteriochlorin. Application of the new acid catalysis conditions has afforded four indium bacteriochlorins bearing aryl, alkyl/ester, or no substituents at the β-pyrrolic positions. The indium bacteriochlorins exhibit (i) a long-wavelength absorption band in the 741-782 nm range, which is shifted bathochromically by 22-32 nm versus the analogous free base species, (ii) fluorescence quantum yields (0.011-0.026) and average singlet lifetime (270 ps) diminished by an order of magnitude versus that (0.13-0.25; 4.0 ns) for the free base analogues, and (iii) higher average yield (0.9 versus 0.5) yet shorter average lifetime (30 vs 105 μs) of the lowest triplet excited state compared to the free base compounds. The differences in the excited-state properties of the indium chelates versus free base bacteriochlorins derive primarily from a 30-fold greater rate constant for S(1) → T(1) intersystem crossing, which stems from the heavy-atom effect on spin-orbit coupling. The trends in optical properties of the indium bacteriochlorins versus free base analogues, and the effects of 5-OMe versus 5-H substituents, correlate well with frontier molecular-orbital energies and energy gaps derived from density functional theory calculations. Collectively the synthesis, photophysical properties, and electronic characteristics of the indium bacteriochlorins and free base analogues reported herein should aid in the further design of such chromophores for diverse applications.}, number={10}, journal={INORGANIC CHEMISTRY}, author={Krayer, Michael and Yang, Eunkyung and Kim, Han-Je and Kee, Hooi Ling and Deans, Richard M. and Sluder, Camille E. and Diers, James R. and Kirmaier, Christine and Bocian, David F. and Holten, Dewey and et al.}, year={2011}, month={May}, pages={4607–4618} }
 @article{ptaszek_lahaye_krayer_muthiah_lindsey_2010, title={De Novo Synthesis of Long-Wavelength Absorbing Chlorin-13,15-dicarboximides}, volume={75}, ISSN={["1520-6904"]}, DOI={10.1021/jo902649d}, abstractNote={Chlorins bearing a six-membered imide ring spanning positions 13-15, commonly referred to as purpurinimides, exhibit long-wavelength absorption yet have heretofore only been available via semisynthesis from naturally occurring chlorophylls. A concise route to synthetic chlorins, which bear a geminal dimethyl group in the pyrroline ring, has been extended to provide access to chlorin-13,15-dicarboximides. The new route entails (i) synthesis of a 13-bromochlorin, (ii) palladium-catalyzed carbamoylation at the 13-position, (iii) regioselective 15-bromination under acidic conditions, and (iv) one-flask palladium-mediated carbonylation and ring closure to form the imide. In some cases the ring closure reaction afforded the isomeric (and readily separable) chlorin-isoimide in addition to the chlorin-imide. The resulting chlorin-imides and chlorin-isoimides exhibit long-wavelength absorption (679-715 nm) and emission (683-720 nm) in the far-red and near-infrared spectral region. The absorption of the chlorin-(iso)imides fills the spectral window between that of analogous synthetic chlorins and 13(1)-oxophorbines (603-687 nm) and bacteriochlorins (707-792 nm). The synthetic versatility of the de novo route complements the existing semisynthetic route from chlorophylls and should enable fundamental spectroscopic studies and photochemical applications.}, number={5}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Ptaszek, Marcin and Lahaye, Dorothee and Krayer, Michael and Muthiah, Chinnasamy and Lindsey, Jonathan S.}, year={2010}, month={Mar}, pages={1659–1673} }
 @article{krayer_ptaszek_kim_meneely_fan_secor_lindsey_2010, title={Expanded Scope of Synthetic Bacteriochlorins via Improved Acid Catalysis Conditions and Diverse Dihydrodipyrrin-Acetals}, volume={75}, ISSN={["0022-3263"]}, DOI={10.1021/jo9025572}, abstractNote={Bacteriochlorins are attractive candidates for a wide variety of photochemical studies owing to their strong absorption in the near-infrared spectral region. The prior acid-catalysis conditions [BF(3) x O(Et)(2) in CH(3)CN at room temperature] for self-condensation of a dihydrodipyrrin-acetal (bearing a geminal dimethyl group in the pyrroline ring) typically afforded a mixture of three macrocycles: the expected 5-methoxybacteriochlorin (MeOBC-type), a 5-unsubstituted bacteriochlorin (HBC-type), and a free base B,D-tetradehydrocorrin (TDC-type). Here, a broad survey of >20 acids identified four promising acid catalysis conditions of which TMSOTf/2,6-di-tert-butylpyridine in CH(2)Cl(2) at room temperature was most attractive owing to formation of the 5-methoxybacteriochlorin as the sole macrocycle regardless of the pyrrolic substituents in the dihydrodipyrrin-acetal (electron-withdrawing, electron-donating, or no substituent). Eleven new dihydrodipyrrin-acetals were prepared following standard routes. Application of the new acid catalysis conditions has afforded diverse bacteriochlorins (e.g., bearing alkyl/ester, aryl/ester, diester, and no substituents) in a few days from commercially available starting materials. Consideration of the synthetic steps and yields for formation of the dihydrodipyrrin-acetal and bacteriochlorin underpins evaluation of synthetic plans for early installation of bacteriochlorin substituents via the dihydrodipyrrin-acetal versus late installation via derivatization of beta-bromobacteriochlorins. Treatment of the 5-methoxybacteriochlorins with NBS gave regioselective 15-bromination when no pyrrolic substituents were present or when each pyrrole contained two substituents; on the other hand, the presence of a beta-ethoxycarbonyl group caused loss of regioselectivity. The 15 new bacteriochlorins prepared herein exhibit a long-wavelength absorption band in the range 707-759 nm, providing tunable access to the near-infrared region. Taken together, this study expands the scope of available bacteriochlorins for fundamental studies and diverse applications.}, number={4}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Krayer, Michael and Ptaszek, Marcin and Kim, Han-Je and Meneely, Kelly R. and Fan, Dazhong and Secor, Kristen and Lindsey, Jonathan S.}, year={2010}, month={Feb}, pages={1016–1039} }
 @article{huang_mroz_zhiyentayev_sharma_balasubramanian_ruzie_krayer_fan_borbas_yang_et al._2010, title={In Vitro Photodynamic Therapy and Quantitative Structure-Activity Relationship Studies with Stable Synthetic Near-Infrared-Absorbing Bacteriochlorin Photosensitizers}, volume={53}, ISSN={["1520-4804"]}, DOI={10.1021/jm901908s}, abstractNote={Photodynamic therapy (PDT) is a rapidly developing approach to treating cancer that combines harmless visible and near-infrared light with a nontoxic photoactivatable dye, which upon encounter with molecular oxygen generates the reactive oxygen species that are toxic to cancer cells. Bacteriochlorins are tetrapyrrole compounds with two reduced pyrrole rings in the macrocycle. These molecules are characterized by strong absorption features from 700 to >800 nm, which enable deep penetration into tissue. This report describes testing of 12 new stable synthetic bacteriochlorins for PDT activity. The 12 compounds possess a variety of peripheral substituents and are very potent in killing cancer cells in vitro after illumination. Quantitative structure-activity relationships were derived, and subcellular localization was determined. The most active compounds have both low dark toxicity and high phototoxicity. This combination together with near-infrared absorption gives these bacteriochlorins great potential as photosensitizers for treatment of cancer.}, number={10}, journal={JOURNAL OF MEDICINAL CHEMISTRY}, author={Huang, Ying-Ying and Mroz, Pawel and Zhiyentayev, Timur and Sharma, Sulbha K. and Balasubramanian, Thiagarajan and Ruzie, Christian and Krayer, Michael and Fan, Dazhong and Borbas, K. Eszter and Yang, Eunkyung and et al.}, year={2010}, month={May}, pages={4018–4027} }
 @article{huang_huang_mroz_tegos_zhiyentayev_sharma_lu_balasubramanian_krayer_ruzie_et al._2010, title={Stable Synthetic Cationic Bacteriochlorins as Selective Antimicrobial Photosensitizers}, volume={54}, ISSN={["1098-6596"]}, DOI={10.1128/aac.00125-10}, abstractNote={Photodynamic inactivation is a rapidly developing antimicrobial treatment that employs a nontoxic photoactivatable dye or photosensitizer in combination with harmless visible light to generate reactive oxygen species that are toxic to cells. Tetrapyrroles (e.g., porphyrins, chlorins, bacteriochlorins) are a class of photosensitizers that exhibit promising characteristics to serve as broad-spectrum antimicrobials. In order to bind to and efficiently penetrate into all classes of microbial cells, tetrapyrroles should have structures that contain (i) one or more cationic charge(s) or (ii) a basic group. In this report, we investigate the use of new stable synthetic bacteriochlorins that have a strong absorption band in the range 720 to 740 nm, which is in the near-infrared spectral region. Four bacteriochlorins with 2, 4, or 6 quaternized ammonium groups or 2 basic amine groups were compared for light-mediated killing against a gram-positive bacterium (Staphylococcus aureus), a gram-negative bacterium (Escherichia coli), and a dimorphic fungal yeast (Candida albicans). Selectivity was assessed by determining phototoxicity against human HeLa cancer cells under the same conditions. All four compounds were highly active (6 logs of killing at 1 microM or less) against S. aureus and showed selectivity for bacteria over human cells. Increasing the cationic charge increased activity against E. coli. Only the compound with basic groups was highly active against C. albicans. Supporting photochemical and theoretical characterization studies indicate that (i) the four bacteriochlorins have comparable photophysical features in homogeneous solution and (ii) the anticipated redox characteristics do not correlate with cell-killing ability. These results support the interpretation that the disparate biological activities observed stem from cellular binding and localization effects rather than intrinsic electronic properties. These findings further establish cationic bacteriochlorins as extremely active and selective near-infrared activated antimicrobial photosensitizers, and the results provide fundamental information on structure-activity relationships for antimicrobial photosensitizers.}, number={9}, journal={ANTIMICROBIAL AGENTS AND CHEMOTHERAPY}, author={Huang, Liyi and Huang, Ying-Ying and Mroz, Pawel and Tegos, George P. and Zhiyentayev, Timur and Sharma, Sulbha K. and Lu, Zongshun and Balasubramanian, Thiagarajan and Krayer, Michael and Ruzie, Christian and et al.}, year={2010}, month={Sep}, pages={3834–3841} }
 @article{mroz_huang_szokalska_zhiyentayev_janjua_nifli_sherwood_ruzie_borbas_fan_et al._2010, title={Stable synthetic bacteriochlorins overcome the resistance of melanoma to photodynamic therapy}, volume={24}, ISSN={["0892-6638"]}, DOI={10.1096/fj.09-152587}, abstractNote={Cutaneous malignant melanoma remains a therapeutic challenge, and patients with advanced disease have limited survival. Photodynamic therapy (PDT) has been successfully used to treat many malignancies, and it may show promise as an antimelanoma modality. However, high melanin levels in melanomas can adversely affect PDT effectiveness. Herein the extent of melanin contribution to melanoma resistance to PDT was investigated in a set of melanoma cell lines that markedly differ in the levels of pigmentation; 3 new bacteriochlorins successfully overcame the resistance. Cell killing studies determined that bacteriochlorins are superior at (LD(50) approximately 0.1 microM) when compared with controls such as the FDA-approved Photofrin (LD(50) approximately 10 microM) and clinically tested LuTex (LD(50) approximately 1 microM). The melanin content affects PDT effectiveness, but the degree of reduction is significantly lower for bacteriochlorins than for Photofrin. Microscopy reveals that the least effective bacteriochlorin localizes predominantly in lysosomes, while the most effective one preferentially accumulates in mitochondria. Interestingly all bacteriochlorins accumulate in melanosomes, and subsequent illumination leads to melanosomal damage shown by electron microscopy. Fluorescent probes show that the most effective bacteriochlorin produces significantly higher levels of hydroxyl radicals, and this is consistent with the redox properties suggested by molecular-orbital calculations. The best in vitro performing bacteriochlorin was tested in vivo in a mouse melanoma model using spectrally resolved fluorescence imaging and provided significant survival advantage with 20% of cures (P<0.01).}, number={9}, journal={FASEB JOURNAL}, author={Mroz, Pawel and Huang, Ying-Ying and Szokalska, Angelika and Zhiyentayev, Timur and Janjua, Sahar and Nifli, Artemissia-Phoebe and Sherwood, Margaret E. and Ruzie, Christian and Borbas, K. Eszter and Fan, Dazhong and et al.}, year={2010}, month={Sep}, pages={3160–3170} }
 @article{ruzie_krayer_lindsey_2009, title={Fast and Robust Route to Hydroporphyrin-Chalcones with Extended Red or Near-Infrared Absorption}, volume={11}, ISSN={["1523-7052"]}, DOI={10.1021/ol900277m}, abstractNote={The reaction of an acetylchlorin or diacetylbacteriochlorin with an aldehyde under microwave conditions readily affords the corresponding hydroporphyrin−chalcone. The aldehydes include aryl aldehydes, cinnamaldehyde, and all-trans-retinal. The chalcone causes a bathochromic shift of the long-wavelength absorption band of the hydroporphyrin by up to 24 nm. The facile conjugation and wavelength tunability should make such constructs valuable for fundamental spectroscopic studies as well as diverse photochemical applications in the relatively unexplored red and near-infrared spectral regions.}, number={8}, journal={ORGANIC LETTERS}, author={Ruzie, Christian and Krayer, Michael and Lindsey, Jonathan S.}, year={2009}, month={Apr}, pages={1761–1764} }
 @article{krayer_balasubramanian_ruzie_ptaszek_cramer_taniguchi_lindsey_2009, title={Refined syntheses of hydrodipyrrin precursors to chlorin and bacteriochlorin building blocks}, volume={13}, ISSN={["1099-1409"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-70450189510&partnerID=MN8TOARS}, DOI={10.1142/S1088424609001406}, abstractNote={Bromo-substituted hydrodipyrrins are valuable precursors to synthetic bromo-chlorins and bromo-bacteriochlorins, which in turn are versatile substrates for derivatization in pursuit of diverse molecular designs. 8-bromo-2,3-dihydro-1-(1,1-dimethoxymethyl)-3,3-dimethyldipyrrin (1) is a crucial precursor in the rational synthesis of the bacteriochlorin building block 3,13-dibromo-8,8,18,18-tetramethylbacteriochlorin ( H 2 BC-Br 3 Br 13 ) . 8-bromo-2,3,4,5-tetrahydro-1,3,3-trimethyldipyrrin (2) is a crucial precursor in the rational synthesis of the analogous 3,13-disubstituted chlorin building block (e.g. H 2 C-Br 3 M 10 Br 13 ). The routes to 1 and 2 share a common precursor, namely 4-bromo-2-(2-nitroethyl)-1-N-tosylpyrrole (6-Ts), which is derived from pyrrole-2-carboxaldehyde. The prior seven-step synthesis of 1 from pyrrole-2-carboxaldehyde has limited access to H 2 BC-Br 3 Br 13 given the large excesses of materials, extensive reliance on column chromatography, and low overall yield (1.4%). Refined procedures for synthesis of the common precursor 6-Ts as well as 1 and 2 afford the advantages of (1) diminished consumption of solvents and reagents, (2) limited or no use of chlorinated solvents, (3) limited or no chromatography, and (4) improved yields of most steps. Streamlined procedures enable the final two or three transformations to be performed without purification of intermediates. The new procedures facilitate the expedient preparation of 1 and 2 at the multigram scale.}, number={10}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, publisher={World Scientific Pub Co Pte Lt}, author={Krayer, Michael and Balasubramanian, Thiagarajan and Ruzie, Christian and Ptaszek, Marcin and Cramer, David L. and Taniguchi, Masahiko and Lindsey, Jonathan S.}, year={2009}, month={Oct}, pages={1098–1110} }
 @article{rogers_krayer_lindsey_melander_2009, title={Tandem dispersion and killing of bacteria from a biofilm}, volume={7}, ISSN={["1477-0539"]}, DOI={10.1039/b817923a}, abstractNote={The combined effects of biofilm dispersion with a 2-aminoimidazole–triazole conjugate and bactericidal activity with a photodynamic inactivation agent suggest a novel combination therapy for treating diverse microbial infections.}, number={3}, journal={ORGANIC & BIOMOLECULAR CHEMISTRY}, author={Rogers, Steven A. and Krayer, Michael and Lindsey, Jonathan S. and Melander, Christian}, year={2009}, pages={603–606} }