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Yuen JM, Harris MA, Liu M, Diers JR, Kirmaier C, Bocian DF, Lindsey JS, Holten D. Effects of substituents on synthetic analogs of chlorophylls. Part 4: How formyl group location dictates the spectral properties of chlorophylls b, d and f. Photochem Photobiol 2015; 91:331-42. [PMID: 25488432 DOI: 10.1111/php.12401] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/03/2014] [Indexed: 12/24/2022]
Abstract
Photosynthetic organisms are adapted to light characteristics in their habitat in part via the spectral characteristics of the associated chlorophyll pigments, which differ in the position of a formyl group around the chlorin macrocycle (chlorophylls b, d, f) or no formyl group (chlorophyll a). To probe the origin of this spectral tuning, the photophysical and electronic structural properties of a new set of synthetic chlorins are reported. The zinc and free base chlorins have a formyl group at either the 2- or 3-position. The four compounds have fluorescence yields in the range 0.19-0.28 and singlet excited-state lifetimes of ca 4 ns for zinc chelates and ca 8 ns for the free base forms. The photophysical properties of the 2- and 3-formyl zinc chlorins are similar to those observed previously for 13-formyl or 3,13-diformyl chlorins, but differ markedly from those for 7-formyl analogs. Molecular-orbital characteristics obtained from density functional theory (DFT) calculations were used as input to spectral simulations employing the four-orbital model. The analysis has uncovered the key changes in electronic structure engendered by the presence/location of a formyl group at various macrocycle positions, which is relevant to understanding the distinct spectral properties of the natural chlorophylls a, b, d and f.
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Faries KM, Diers JR, Springer JW, Yang E, Ptaszek M, Lahaye D, Krayer M, Taniguchi M, Kirmaier C, Lindsey JS, Bocian DF, Holten D. Photophysical Properties and Electronic Structure of Chlorin-Imides: Bridging the Gap between Chlorins and Bacteriochlorins. J Phys Chem B 2015; 119:7503-15. [DOI: 10.1021/jp511257w] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Jiang J, Yang E, Reddy KR, Niedzwiedzki DM, Kirmaier C, Bocian DF, Holten D, Lindsey JS. Synthetic bacteriochlorins bearing polar motifs (carboxylate, phosphonate, ammonium and a short PEG). Water-solubilization, bioconjugation, and photophysical properties. NEW J CHEM 2015. [DOI: 10.1039/c5nj00759c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A bacteriochlorin scaffold has been derivatized for life sciences applications.
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Alexy EJ, Yuen JM, Chandrashaker V, Diers JR, Kirmaier C, Bocian DF, Holten D, Lindsey JS. Panchromatic absorbers for solar light-harvesting. Chem Commun (Camb) 2014; 50:14512-5. [PMID: 25308466 DOI: 10.1039/c4cc06853j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
A set of panchromatic absorbers exhibiting long excited-state lifetimes in both polar and nonpolar media has been prepared. The architectures are based on a porphyrin strongly coupled electronically to 1-4 perylene-monoimides via ethyne linkers. The constructs should find utility in molecular solar-conversion systems.
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Kressel L, Faries KM, Wander MJ, Zogzas CE, Mejdrich RJ, Hanson DK, Holten D, Laible PD, Kirmaier C. High yield of secondary B-side electron transfer in mutant Rhodobacter capsulatus reaction centers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1892-1903. [DOI: 10.1016/j.bbabio.2014.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/22/2014] [Accepted: 07/26/2014] [Indexed: 10/25/2022]
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Jiang J, Reddy KR, Pavan MP, Lubian E, Harris MA, Jiao J, Niedzwiedzki DM, Kirmaier C, Parkes-Loach PS, Loach PA, Bocian DF, Holten D, Lindsey JS. Amphiphilic, hydrophilic, or hydrophobic synthetic bacteriochlorins in biohybrid light-harvesting architectures: consideration of molecular designs. PHOTOSYNTHESIS RESEARCH 2014; 122:187-202. [PMID: 24997120 DOI: 10.1007/s11120-014-0021-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 05/26/2014] [Indexed: 06/03/2023]
Abstract
Biohybrid light-harvesting architectures can be constructed that employ native-like bacterial photosynthetic antenna peptides as a scaffold to which synthetic chromophores are attached to augment overall spectral coverage. Synthetic bacteriochlorins are attractive to enhance capture of solar radiation in the photon-rich near-infrared spectral region. The effect of the polarity of the bacteriochlorin substituents on the antenna self-assembly process was explored by the preparation of a bacteriochlorin-peptide conjugate using a synthetic amphiphilic bacteriochlorin (B1) to complement prior studies using hydrophilic (B2, four carboxylic acids) or hydrophobic (B3) bacteriochlorins. The amphiphilic bioconjugatable bacteriochlorin B1 with a polar ammonium-terminated tail was synthesized by sequential Pd-mediated reactions of a 3,13-dibromo-5-methoxybacteriochlorin. Each bacteriochlorin bears a maleimido-terminated tether for attachment to a cysteine-containing analog of the Rhodobacter sphaeroides antenna β-peptide to give conjugates β-B1, β-B2, and β-B3. Given the hydrophobic nature of the β-peptide, the polarity of B1 and B2 facilitated purification of the respective conjugate compared to the hydrophobic B3. Bacteriochlorophyll a (BChl a) associates with each conjugate in aqueous micellar media to form a dyad containing two β-peptides, two covalently attached synthetic bacteriochlorins, and a datively bonded BChl-a pair, albeit to a limited extent for β-B2. The reversible assembly/disassembly of dyad (β-B2/BChl)2 was examined in aqueous detergent (octyl glucoside) solution by temperature variation (15-35 °C). The energy-transfer efficiency from the synthetic bacteriochlorin to the BChl-a dimer was found to be 0.85 for (β-B1/BChl)2, 0.40 for (β-B2/BChl)2, and 0.85 for (β-B3/BChl)2. Thus, in terms of handling, assembly and energy-transfer efficiency taken together, the amphiphilic design examined herein is more attractive than the prior hydrophilic or hydrophobic designs.
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Chi SC, Mothersole DJ, Dilbeck P, Niedzwiedzki DM, Zhang H, Qian P, Vasilev C, Grayson KJ, Jackson PJ, Martin EC, Li Y, Holten D, Neil Hunter C. Assembly of functional photosystem complexes in Rhodobacter sphaeroides incorporating carotenoids from the spirilloxanthin pathway. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:189-201. [PMID: 25449968 PMCID: PMC4331045 DOI: 10.1016/j.bbabio.2014.10.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/17/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022]
Abstract
Carotenoids protect the photosynthetic apparatus against harmful radicals arising from the presence of both light and oxygen. They also act as accessory pigments for harvesting solar energy, and are required for stable assembly of many light-harvesting complexes. In the phototrophic bacterium Rhodobacter (Rba.) sphaeroides phytoene desaturase (CrtI) catalyses three sequential desaturations of the colourless carotenoid phytoene, extending the number of conjugated carbon–carbon double bonds, N, from three to nine and producing the yellow carotenoid neurosporene; subsequent modifications produce the yellow/red carotenoids spheroidene/spheroidenone (N = 10/11). Genomic crtI replacements were used to swap the native three-step Rba. sphaeroides CrtI for the four-step Pantoea agglomerans enzyme, which re-routed carotenoid biosynthesis and culminated in the production of 2,2′-diketo-spirilloxanthin under semi-aerobic conditions. The new carotenoid pathway was elucidated using a combination of HPLC and mass spectrometry. Premature termination of this new pathway by inactivating crtC or crtD produced strains with lycopene or rhodopin as major carotenoids. All of the spirilloxanthin series carotenoids are accepted by the assembly pathways for LH2 and RC–LH1–PufX complexes. The efficiency of carotenoid-to-bacteriochlorophyll energy transfer for 2,2′-diketo-spirilloxanthin (15 conjugated C
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>C bonds; N = 15) in LH2 complexes is low, at 35%. High energy transfer efficiencies were obtained for neurosporene (N = 9; 94%), spheroidene (N = 10; 96%) and spheroidenone (N = 11; 95%), whereas intermediate values were measured for lycopene (N = 11; 64%), rhodopin (N = 11; 62%) and spirilloxanthin (N = 13; 39%). The variety and stability of these novel Rba. sphaeroides antenna complexes make them useful experimental models for investigating the energy transfer dynamics of carotenoids in bacterial photosynthesis. The spirilloxanthin biosynthetic pathway has been constructed in Rba. sphaeroides. The new carotenoids are accepted by the photosystem assembly pathways. These pigments are efficiently integrated into LH2 and RC–LH1–PufX complexes. Carotenoid–BChl energy transfer drops with the number of conjugated CC bonds (N). The lowest efficiency, 35%, is for the N = 15 carotenoid 2,2′ diketospirilloxanthin.
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Huang L, Krayer M, Roubil JGS, Huang YY, Holten D, Lindsey JS, Hamblin MR. Stable synthetic mono-substituted cationic bacteriochlorins mediate selective broad-spectrum photoinactivation of drug-resistant pathogens at nanomolar concentrations. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 141:119-27. [PMID: 25463659 DOI: 10.1016/j.jphotobiol.2014.09.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/14/2022]
Abstract
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.
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Harris MA, Sahin T, Jiang J, Vairaprakash P, Parkes-Loach PS, Niedzwiedzki DM, Kirmaier C, Loach PA, Bocian DF, Holten D, Lindsey JS. Enhanced Light-Harvesting Capacity by Micellar Assembly of Free Accessory Chromophores and LH1-like Antennas. Photochem Photobiol 2014; 90:1264-76. [DOI: 10.1111/php.12319] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/11/2014] [Indexed: 01/05/2023]
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Harris MA, Jiang J, Niedzwiedzki DM, Jiao J, Taniguchi M, Kirmaier C, Loach PA, Bocian DF, Lindsey JS, Holten D, Parkes-Loach PS. Versatile design of biohybrid light-harvesting architectures to tune location, density, and spectral coverage of attached synthetic chromophores for enhanced energy capture. PHOTOSYNTHESIS RESEARCH 2014; 121:35-48. [PMID: 24604033 DOI: 10.1007/s11120-014-9993-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/22/2014] [Indexed: 06/03/2023]
Abstract
Biohybrid antennas built upon chromophore-polypeptide conjugates show promise for the design of efficient light-capturing modules for specific purposes. Three new designs, each of which employs analogs of the β-polypeptide from Rhodobacter sphaeroides, have been investigated. In the first design, amino acids at seven different positions on the polypeptide were individually substituted with cysteine, to which a synthetic chromophore (bacteriochlorin or Oregon Green) was covalently attached. The polypeptide positions are at -2, -6, -10, -14, -17, -21, and -34 relative to the 0-position of the histidine that coordinates bacteriochlorophyll a (BChl a). All chromophore-polypeptides readily formed LH1-type complexes upon combination with the α-polypeptide and BChl a. Efficient energy transfer occurs from the attached chromophore to the circular array of 875 nm absorbing BChl a molecules (denoted B875). In the second design, use of two attachment sites (positions -10 and -21) on the polypeptide affords (1) double the density of chromophores per polypeptide and (2) a highly efficient energy-transfer relay from the chromophore at -21 to that at -10 and on to B875. In the third design, three spectrally distinct bacteriochlorin-polypeptides were prepared (each attached to cysteine at the -14 position) and combined in an ~1:1:1 mixture to form a heterogeneous mixture of LH1-type complexes with increased solar coverage and nearly quantitative energy transfer from each bacteriochlorin to B875. Collectively, the results illustrate the great latitude of the biohybrid approach for the design of diverse light-harvesting systems.
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Diers JR, Tang Q, Hondros CJ, Chen CY, Holten D, Lindsey JS, Bocian DF. Vibronic Characteristics and Spin-Density Distributions in Bacteriochlorins as Revealed by Spectroscopic Studies of 16 Isotopologues. Implications for Energy- and Electron-Transfer in Natural Photosynthesis and Artificial Solar-Energy Conversion. J Phys Chem B 2014; 118:7520-7532. [DOI: 10.1021/jp504286w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Saggu M, Carter B, Zhou X, Faries K, Cegelski L, Holten D, Boxer SG, Kirmaier C. Putative hydrogen bond to tyrosine M208 in photosynthetic reaction centers from Rhodobacter capsulatus significantly slows primary charge separation. J Phys Chem B 2014; 118:6721-32. [PMID: 24902471 PMCID: PMC4064694 DOI: 10.1021/jp503422c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
Slow, ∼50
ps, P* → P+HA– electron
transfer is observed in Rhodobacter
capsulatus reaction centers (RCs) bearing the native
Tyr residue at M208 and the single amino acid change of isoleucine
at M204 to glutamic acid. The P* decay kinetics are unusually homogeneous
(single exponential) at room temperature. Comparative solid-state
NMR of [4′-13C]Tyr labeled wild-type and M204E RCs
show that the chemical shift of Tyr M208 is significantly altered
in the M204E mutant and in a manner consistent with formation of a
hydrogen bond to the Tyr M208 hydroxyl group. Models based on RC crystal
structure coordinates indicate that if such a hydrogen bond is formed
between the Glu at M204 and the M208 Tyr hydroxyl group, the −OH
would be oriented in a fashion expected (based on the calculations
by Alden et al., J. Phys. Chem.1996, 100, 16761–16770) to destabilize P+BA– in free energy. Alteration
of the environment of Tyr M208 and BA by Glu M204 via this
putative hydrogen bond has a powerful influence on primary charge
separation.
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Yang E, Wang J, Diers JR, Niedzwiedzki DM, Kirmaier C, Bocian DF, Lindsey JS, Holten D. Probing electronic communication for efficient light-harvesting functionality: dyads containing a common perylene and a porphyrin, chlorin, or bacteriochlorin. J Phys Chem B 2014; 118:1630-47. [PMID: 24484243 DOI: 10.1021/jp411629m] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The synthesis, photophysical, redox, and molecular-orbital characteristics of three perylene-tetrapyrrole dyads were investigated to probe the efficacy of the arrays for use as light-harvesting constituents. Each dyad contains a common perylene-monoimide that is linked at the N-imide position via an arylethynyl group to the meso-position of the tetrapyrrole. The tetrapyrroles include a porphyrin, chlorin, and bacteriochlorin, which have zero, one, and two reduced pyrrole rings, respectively. The increased pyrrole-ring reduction results in a progressive red shift and intensification of the lowest-energy absorption band, as exemplified by benchmark monomers. The arylethyne linkage affords moderate perylene-tetrapyrrole electronic coupling in the dyads as evidenced by the optical, molecular-orbital, and redox properties of the components of the dyads versus the constituent parts. All three dyads in nonpolar solvents exhibit relatively fast (subpicosecond) energy transfer from the perylene to the tetrapyrrole. Competing charge-transfer processes are also absent in nonpolar solvents, but become active for both the chlorin and bacteriochlorin-containing dyads in polar solvents. Calculations of energy-transfer rates via the Förster, through-space mechanism reveal that these rates are, on average, 3-fold slower than the observed rates. Thus, the Dexter through-bond mechanism contributes more substantially than the through-space mechanism to energy transfer in the dyads. The electronic communication between the perylene and tetrapyrrole falls in a regime intermediate between those operative in other classes of perylene-tetrapyrrole dyads that have previously been studied.
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Springer JW, Taniguchi M, Krayer M, Ruzié C, Diers JR, Niedzwiedzki DM, Bocian DF, Lindsey JS, Holten D. Photophysical properties and electronic structure of retinylidene–chlorin–chalcones and analogues. Photochem Photobiol Sci 2014; 13:634-50. [DOI: 10.1039/c3pp50421b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kirmaier C, Holten D. Subpicosecond Spectroscopy of Charge Separation inRhodobacter capsulatusReaction Centers. Isr J Chem 2013. [DOI: 10.1002/ijch.198800016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wang J, Yang E, Diers JR, Niedzwiedzki DM, Kirmaier C, Bocian DF, Lindsey JS, Holten D. Distinct Photophysical and Electronic Characteristics of Strongly Coupled Dyads Containing a Perylene Accessory Pigment and a Porphyrin, Chlorin, or Bacteriochlorin. J Phys Chem B 2013; 117:9288-304. [DOI: 10.1021/jp405004d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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67
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Harris MA, Luehr CA, Faries KM, Wander M, Kressel L, Holten D, Hanson DK, Laible PD, Kirmaier C. Protein Influence on Charge-Asymmetry of the Primary Donor in Photosynthetic Bacterial Reaction Centers Containing a Heterodimer: Effects on Photophysical Properties and Electron Transfer. J Phys Chem B 2013; 117:4028-41. [DOI: 10.1021/jp401138h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Yang E, Ruzié C, Krayer M, Diers JR, Niedzwiedzki DM, Kirmaier C, Lindsey JS, Bocian DF, Holten D. Photophysical properties and electronic structure of bacteriochlorin-chalcones with extended near-infrared absorption. Photochem Photobiol 2013; 89:586-604. [PMID: 23360219 DOI: 10.1111/php.12053] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/21/2013] [Indexed: 02/06/2023]
Abstract
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.
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Yang E, Diers JR, Huang YY, Hamblin MR, Lindsey JS, Bocian DF, Holten D. Molecular electronic tuning of photosensitizers to enhance photodynamic therapy: synthetic dicyanobacteriochlorins as a case study. Photochem Photobiol 2013; 89:605-18. [PMID: 23163632 DOI: 10.1111/php.12021] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 11/11/2012] [Indexed: 01/01/2023]
Abstract
Photophysical, photostability, electrochemical and molecular-orbital characteristics are analyzed for a set of stable dicyanobacteriochlorins that are promising photosensitizers for photodynamic therapy (PDT). The bacteriochlorins are the parent compound (BC), dicyano derivative (NC)2BC and corresponding zinc (NC)2BC-Zn and palladium chelate (NC)2BC-Pd. The order of PDT activity against HeLa human cancer cells in vitro is (NC)2BC-Pd > (NC)2BC > (NC)2BC-Zn ≈ BC. The near-infrared absorption feature of each dicyanobacteriochlorin is bathochromically shifted 35-50 nm (748-763 nm) from that for BC (713 nm). Intersystem crossing to the PDT-active triplet excited state is essentially quantitative for (NC)2BC-Pd. Phosphorescence from (NC)2BC-Pd occurs at 1122 nm (1.1 eV). This value and the measured ground-state redox potentials fix the triplet excited-state redox properties, which underpin PDT activity via Type-1 (electron transfer) pathways. A perhaps counterintuitive (but readily explicable) result is that of the three dicyanobacteriochlorins, the photosensitizer with the shortest triplet lifetime (7 μs), (NC)2BC-Pd has the highest activity. Photostabilities of the dicyanobacteriochlorins and other bacteriochlorins studied recently are investigated and discussed in terms of four phenomena: aggregation, reduction, oxidation and chemical reaction. Collectively, the results and analysis provide fundamental insights concerning the molecular design of PDT agents.
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Aravindu K, Mass O, Vairaprakash P, Springer JW, Yang E, Niedzwiedzki DM, Kirmaier C, Bocian DF, Holten D, Lindsey JS. Amphiphilic chlorins and bacteriochlorins in micellar environments. Molecular design, de novo synthesis, and photophysical properties. Chem Sci 2013. [DOI: 10.1039/c3sc51335a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Reddy KR, Jiang J, Krayer M, Harris MA, Springer JW, Yang E, Jiao J, Niedzwiedzki DM, Pandithavidana D, Parkes-Loach PS, Kirmaier C, Loach PA, Bocian DF, Holten D, Lindsey JS. Palette of lipophilic bioconjugatable bacteriochlorins for construction of biohybrid light-harvesting architectures. Chem Sci 2013. [DOI: 10.1039/c3sc22317e] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Aravindu K, Kim HJ, Taniguchi M, Dilbeck PL, Diers JR, Bocian DF, Holten D, Lindsey JS. Synthesis and photophysical properties of chlorins bearing 0–4 distinct meso-substituents. Photochem Photobiol Sci 2013; 12:2089-109. [DOI: 10.1039/c3pp50240f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Harris MA, Parkes-Loach PS, Springer JW, Jiang J, Martin EC, Qian P, Jiao J, Niedzwiedzki DM, Kirmaier C, Olsen JD, Bocian DF, Holten D, Hunter CN, Lindsey JS, Loach PA. Integration of multiple chromophores with native photosynthetic antennas to enhance solar energy capture and delivery. Chem Sci 2013. [DOI: 10.1039/c3sc51518d] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Reddy KR, Lubian E, Pavan MP, Kim HJ, Yang E, Holten D, Lindsey JS. Synthetic bacteriochlorins with integral spiro-piperidine motifs. NEW J CHEM 2013. [DOI: 10.1039/c3nj41161c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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75
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Sharma SK, Krayer M, Sperandio FF, Huang L, Huang YY, Holten D, Lindsey JS, Hamblin MR. Synthesis and evaluation of cationic bacteriochlorin amphiphiles with effective in vitro photodynamic activity against cancer cells at low nanomolar concentration. J PORPHYR PHTHALOCYA 2013; 17:73-85. [PMID: 23956614 PMCID: PMC3742135 DOI: 10.1142/s108842461250126x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
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.
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