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

Diers, James R.; Tang, Qun; Hondros, Christopher J.; Chen, Chih-Yuan; Holten, Dewey; Lindsey, Jonathan S.; Bocian, David F.

doi:10.1021/jp504286w

Cited by 14 publications

(11 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such 'Stokes shift' is smaller than for BC-MEs or BC-EEs (Table 2) or other bacteriochlorins bearing simple substituents (e.g., methyl, ethyl, phenyl, ester, acetyl, ethynyl) at the 2,3,12,13positions, which give an average shift of B4 nm (B90 cm À1 ). The low-and mid-frequency regions (150-1700 cm À1 ) of the Q y -excitation RR spectrum of CuBC-MM (l ex = 737 nm) is compared with that previously reported 46 for CuBC0 (l ex = 730 nm) in Fig. 14 (B) Resonance Raman studies of CuBC-MM.…”

Section: (Ii) Photophysical Characterizationmentioning

confidence: 82%

Synthesis and photophysical characteristics of 2,3,12,13-tetraalkylbacteriochlorins

et al. 2016

Self Cite

View full text Add to dashboard Cite

Bacteriochlorins absorb strongly in the near-infrared spectral region and hence are of great interest across the field of photochemistry. The established de novo self-condensation of a dihydrodipyrrinacetal has afforded stable bacteriochlorins bearing a variety of b-pyrrolic substituents, but the route was incompatible with the presence of two alkyl groups. The lacuna stemmed from the instability of the dialkyl-substituted dihydrodipyrrin-acetal. Here, two dihydrodipyrrin-carboxaldehydes, each bearing a tert-butoxycarbonyl group at the pyrrole a-position, were prepared and found to be stable to routine handling. Each ester-substituted dihydrodipyrrin-carboxaldehyde in acid underwent in situ ester cleavage and ensuing self-condensation to provide the corresponding 2,3,12,13-tetraalkylbacteriochlorin.The alkyl groups examined include methyl and methyl acetate. Such synthetic bacteriochlorins, while previously unknown, provide valuable models of the natural chromophores. The absorption and fluorescence characteristics of the tetraalkylbacteriochlorins are generally typical for this genre of macrocycle. The X-ray structure of the tetramethylbacteriochlorin reveals that the pyrrolinic (reduced) rings are modestly more twisted out-of-plane (torsional angle B111) than those of the nearly planar (torsional angle B11) parent bacteriochlorin that lacks pyrrolic tetraalkyl groups. The resonance Raman spectrum of the tetramethylbacteriochlorin is also far richer in the low-to mid-frequency region than that of the unsubstituted analogue, but like the unsubstituted counterpart, is far sparser in the highfrequency region than that of native bacteriochlorophyll. Access to tetraalkylbacteriochlorins constitutes one step on the path from the most simple, fully unsubstituted bacteriochlorin to the fully decorated, natural bacteriochlorophylls.

show abstract

Section: (Ii) Photophysical Characterizationmentioning

confidence: 82%

Synthesis and photophysical characteristics of 2,3,12,13-tetraalkylbacteriochlorins

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…The voltammetric measurements were performed at room temperature and in an inert atmosphere glovebox using methods and instrumentation previously described …”

Section: Methodsmentioning

confidence: 99%

Origin of Panchromaticity in Multichromophore–Tetrapyrrole Arrays

et al. 2018

Self Cite

View full text Add to dashboard Cite

Panchromatic absorbers that have robust photophysical properties enable new designs for molecular-based light-harvesting systems. Herein, we report experimental and theoretical studies of the spectral, redox, and excited-state properties of a series of perylene-monoimide-ethyne-porphyrin arrays wherein the number of perylene-monoimide units is stepped from one to four. In the arrays, a profound shift of absorption intensity from the strong violet-blue (B and B) bands of typical porphyrins into the green, red, and near-infrared (Q and Q) regions stems from mixing of chromophore and tetrapyrrole molecular orbitals (MOs), which gives multiplets of MOs having electron density spread over the entire array. This reduces the extensive mixing between porphyrin excited-state configurations and the transition-dipole addition and subtraction that normally leads to intense B and weak Q bands. Reduced configurational mixing derives from moderate effects of the ethyne and perylene on the MO energies and a more substantial effect of electron-density delocalization to reduce the configuration-interaction energy. Quantitative oscillator-strength analysis shows that porphyrin intensity is also shifted into the perylene-like green-region absorption and that the ethyne linkers lend absorption intensity. The reduced porphyrin configurational mixing also endows the S state with bacteriochlorin-like properties, including a 1-5 ns lifetime.

show abstract

“…Electrochemical studies were performed using a standard three-electrode cell, as described previously. 39 2.4. Computational Calculations.…”

Section: Introductionmentioning

confidence: 99%

Effects of Strong Electronic Coupling in Chlorin and Bacteriochlorin Dyads

et al. 2016

Self Cite

View full text Add to dashboard Cite

Achieving tunable, intense near-infrared absorption in molecular architectures with properties suitable for solar light harvesting and biomedical studies is of fundamental interest. Herein, we report the photophysical, redox, and molecular-orbital characteristics of nine hydroporphyrin dyads and associated benchmark monomers that have been designed and synthesized to attain enhanced light harvesting. Each dyad contains two identical hydroporphyrins (chlorin or bacteriochlorin) connected by a linker (ethynyl or butadiynyl) at the macrocycle β-pyrrole (3- or 13-) or meso (15-) positions. The strong electronic communication between constituent chromophores is indicated by the doubling of prominent absorption features, split redox waves, and paired linear combinations of frontier molecular orbitals. Relative to the benchmarks, the chlorin dyads in toluene show substantial bathochromic shifts of the long-wavelength absorption band (17-31 nm), modestly reduced singlet excited-state lifetimes (τS = 3.6-6.2 ns vs 8.8-12.3 ns), and increased fluorescence quantum yields (Φf = 0.37-0.57 vs 0.34-0.39). The bacteriochlorin dyads in toluene show significant bathochromic shifts (25-57 nm) and modestly reduced τS (1.6-3.4 ns vs 3.5-5.3 ns) and Φf (0.09-0.19 vs 0.17-0.21) values. The τS and Φf values for the bacteriochlorin dyads are reduced substantially (up to ∼20-fold) in benzonitrile. The quenching is due primarily to the increased S1 → S0 internal conversion that is likely induced by increased contribution of charge-resonance configurations to the S1 excited state in the polar medium. The fundamental insights gained into the physicochemical properties of the strongly coupled hydroporphyrin dyads may aid their utilization in solar-energy conversion and photomedicine.

show abstract

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

Cited by 14 publications

References 60 publications

Synthesis and photophysical characteristics of 2,3,12,13-tetraalkylbacteriochlorins

Synthesis and photophysical characteristics of 2,3,12,13-tetraalkylbacteriochlorins

Origin of Panchromaticity in Multichromophore–Tetrapyrrole Arrays

Effects of Strong Electronic Coupling in Chlorin and Bacteriochlorin Dyads

Contact Info

Product

Resources

About