Conjugated-linker dependence of the photophysical properties and electronic structure of chlorin dyads

2021 ◽  
pp. A-Y
Author(s):  
Hyun Suk Kang ◽  
Andrius Satraitis ◽  
Adam Meares ◽  
Ganga Viswanathan Bhagavathy ◽  
James R. Diers ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Photophysical Properties ◽  
Bathochromic Shift ◽  
Fluorescence Yield ◽  
Quantum Yields ◽  
Design Strategies ◽  
Long Wavelength ◽  
Fluorescence Quantum Yields ◽  
Wavelength Absorption

The synthesis, photophysical properties and electronic structure of seven new chlorin dyads and associated benchmark monomers are described. Each dyad contains two identical chlorins linked at the macrocycle [Formula: see text]-pyrrole 13-position. The extent of electronic communication between chlorin constituents depends on the nature of the conjugated linker. The communication is assessed by modification of prominent ground-state absorption and redox properties, rate constants and yields of excited-state decay processes, and molecular-orbital characteristics. Relative to the benchmark monomers, the chlorin dyads in toluene exhibit a substantial bathochromic shift of the long-wavelength absorption band (30 nm average), two-fold increased radiative rate constant [average (10 ns)[Formula: see text] vs. (22 ns)[Formula: see text]], reduced singlet excited-state lifetimes (average 5.0 ns vs. 8.2 ns), and increased fluorescence quantum yields (average 0.56 vs. 0.42). The excited-state lifetime and fluorescence yield for the chlorin dyad with a benzothiadiazole linker are reduced substantially in benzonitrile vs. toluene due largely to [Formula: see text]25-fold accelerated internal conversion. The results aid design strategies for molecular architectures that may find utility in solar-energy conversion and photomedicine.

scholarly journals Pyrrolylquinoline-BF2 and BPh2 BODIPY-Type Analogues: Synthesis, Structural Analysis and Photophysical Properties

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1103
Author(s):  
Abdulrahman A. Alsimaree ◽  
Omar M. Alatawi ◽  
Paul G. Waddell ◽  
David P. Day ◽  
Nawaf I. Alsenani ◽  
...  
Keyword(s):  
Energy Gap ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Quantum Yields ◽  
Lumo Energy ◽  
Boron Chelates ◽  
Long Wavelength ◽  
Wavelength Absorption ◽  
Wavelength Emission ◽  
Homo Lumo

Two new pyrrolylquinoline-substituted heteroaromatic-containing compounds bearing a central boron bridge have been prepared by a short, high-yielding sequence consisting of Suzuki-coupling of 8-bromoquinoline and N-Boc 2-pyrroleboronic acid, thermolytic tert-butyloxycarbonyl deprotection, and subsequent boron chelation (either using boron trifluoride or triphenylborane). Both derivatives display longer wavelength absorption maxima (λabsmax) than a previously reported indolopyridine-BPh2 analogue, in agreement with the smaller HOMO-LUMO energy gap predicted by DFT quantum chemical calculations. Both of the pyrrolylquinoline-boron chelates display weak emission (quantum yields 0.3–0.9%) and the BPh2 complex displays a very broad, long-wavelength emission (λemmax = 715 nm, MeCN), which may be due to dimer emission and results in a large pseudo-Stokes’ shift (7753 cm−1) for this compound.

Regioselective Oxidative Cross-Coupling Reaction: Synthesis of Imidazo[1,2-a]pyridine Fluorophores

Synthesis ◽  
2021 ◽  
Author(s):  
Xianglong Chu ◽  
Yadi Niu ◽  
Chen Ma ◽  
Xiaodong Wang ◽  
Yunliang Lin ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Cross Coupling Reaction ◽  
Color Tunable ◽  
Palladium Catalyzed ◽  
Structure Relationship ◽  
High Fluorescence

AbstractA rapid access to a series of N-heteroarene fluorophores has been developed on the basis of the palladium-catalyzed direct oxidative C–H/C–H coupling of imidazo[1,2-a]pyridines with thiophenes/furans. The photophysical properties–structure relationship was systematically investigated. The resulting N-heteroarene fluorophores present color-tunable emissions (λem: 431–507 nm in CH2Cl2) and high fluorescence quantum yields (up to 91% in CH2Cl2).

scholarly journals Indenopyrans – synthesis and photoluminescence properties

2016 ◽  
Vol 12 ◽  
pp. 825-834 ◽  
Author(s):  
Andreea Petronela Diac ◽  
Ana-Maria Ţepeş ◽  
Albert Soran ◽  
Ion Grosu ◽  
Anamaria Terec ◽  
...  
Keyword(s):  
Solid State ◽  
Emission Band ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Band Broadening ◽  
Photoluminescence Properties ◽  
Fluorescence Quantum Yields ◽  
Blue Emitters ◽  
Solid State Fluorescence

New indeno[1,2-c]pyran-3-ones bearing different substituents at the pyran moiety were synthesized and their photophysical properties were investigated. In solution all compounds were found to be blue emitters and the trans isomers exhibited significantly higher fluorescence quantum yields (relative to 9,10-diphenylanthracene) as compared to the corresponding cis isomers. The solid-state fluorescence spectra revealed an important red shift of λmax due to intermolecular interactions in the lattice, along with an emission-band broadening, as compared to the solution fluorescence spectra.

Steric Effects in the Electronic Spectra of the 3,5-Diarylaminobenzene Derivatives

1986 ◽  
Vol 41 (11) ◽  
pp. 1311-1314 ◽  
Author(s):  
A. Balter ◽  
W. Nowak ◽  
P. Milart ◽  
J. Sepioł
Keyword(s):  
Excited State ◽  
Electronic Spectra ◽  
Fluorescence Properties ◽  
Steric Effects ◽  
Quantum Yields ◽  
Spectroscopic Behaviour ◽  
Fluorescence Quantum Yields ◽  
Excited State Lifetimes ◽  
Methyl Phenyl

Absorption and fluorescence properties, excited state lifetimes and fluorescence quantum yields were determined for a series of 3,5-diarylaminobenzene derivatives in solvents of different polarities. The role of the nitrile, methyl, phenyl and naphthyl substituents is discussed. Especially the steric effects on the spectroscopic behaviour of the investigated molecules are studied.

Synthesis and Photophysical Properties of 3-(Trifluoromethyl)-2H-imidazo[5,1-a]isoquinolinium Chloride Derivatives

Synlett ◽  
2017 ◽  
Vol 29 (03) ◽  
pp. 296-300 ◽  
Author(s):  
Ali Darehkordi ◽  
Fariba Rahmani ◽  
Mahin Ramezani ◽  
Alireza Bazmandegan-Shamili
Keyword(s):  
Blue Light ◽  
Uv Radiation ◽  
Photophysical Properties ◽  
Molecular Probes ◽  
Quantum Yields ◽  
Light Emitting ◽  
Fluorescence Studies ◽  
Fluorescence Quantum Yields ◽  
Fluorescent Molecular Probes ◽  
Stokes Shifts

A series of novel blue-light-emitting 2H-imidazo[5,1-a]isoquinolinium chloride derivatives were synthesized by the reaction of isoquinoline with trifluoroacetimidoyl chlorides and isocyanides in dry CH2Cl2 in excellent yields. Fluorescence studies showed that the compounds absorb UV radiation and then emit blue light at about 481 nm with moderate to good fluorescence quantum yields. These compounds also showed high Stokes shifts, and can be used to develop ­ultrasensitive fluorescent molecular probes to study a variety of biological events and processes.

Excited state acid–base equilibrium of tyrosine

1978 ◽  
Vol 56 (9) ◽  
pp. 1238-1245 ◽  
Author(s):  
David Michael Rayner ◽  
Donald Theodore Krajcarski ◽  
Arthur Gustav Szabo
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Quantum Yields ◽  
Acid Base ◽  
Large Shift ◽  
Fluorescence Quantum Yields ◽  
Base Equilibrium ◽  
Tyrosine Fluorescence ◽  
Acid Base Equilibrium ◽  
Buffer Base

Fluorescence attributable to the tyrosinate form of the amino acid tyrosine, previously only observed at pH > pK(S0) = 10.3 where tyrosinate exists in the ground state, has been observed at neutral pH in the presence of high buffer base concentrations. This observation is consistent with the large shift in pK(Sl) predicted from absorption measurements and confirms that proton transfer is indeed a mechanism by which carboxylate ions quench tyrosine fluorescence. The dependence of the fluorescence quantum yields of tyrosine and tyrosinate on pH does not fit a simple excited state acid–base equilibrium model but a more complicated system where carboxylate is also capable of simultaneously quenching tyrosine fluorescence by a mechanism not involving proton transfer. Kinetic analysis of the system allows calculation of pK(S1) = 4.2 for tyrosine. The quantum yield of tyrosinate fluorescence can be appreciably higher than that normally measured at alkaline pH where a separate quenching mechanism must operate. These results have significance in the interpretation of the fluorescence properties of proteins.

scholarly journals A Singlet Oxygen Photogeneration and Luminescence Study of Unsymmetrically Substituted Mesoporphyrinic Compounds

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Anabela Sousa Oliveira ◽  
Dumitru Licsandru ◽  
Rica Boscencu ◽  
Radu Socoteanu ◽  
Veronica Nacea ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Mean Values ◽  
Oxygen Generation ◽  
Fluorescence Quantum Yields ◽  
Thermally Activated ◽  
Phosphorescence Emission ◽  
Photophysical Studies

This paper deals with a series of new unsymmetrically substituted mesoporphyrins: 5-(2-hydroxyphenyl)-10,15,20-tris-phenyl-21,23-H-porphyrin (TPPOHO), 5-(3-hydroxyphenyl)-10,15,20-tris-phenyl-21,23-H-porphyrin (TPPOHM), 5-(4-hydroxyphenyl)-10,15,20-tris-phenyl-21,23-H-porphyrin (TPPOHP), 5-(2-hydroxyphenyl)-10,15,20-tris-butyl-21,23-H-porphyrin (TBPOHO), and their parent nonsubstituted compounds, respectively, 5,10,15,20-tetrakis-phenyl-21,23-H-porphyrin (TPP) and 5,10,15,20-tetrakis-butyl-21,23-H-porphyrin (TBP). Several photophysical studies were carried out to access the influence of the unsymmetrical substitution at the porphyrinic macrocycle on porthyrin's photophysical properties, especially porthyrin's efficiency as singlet oxygen sensitizers. The quantum yields of singlet oxygen generation were determined in benzene (ΦΔ(TPP) = 0.66 ± 0.05;ΦΔ(TPPOHO) = 0.69 ± 0.04;ΦΔ(TPPOHM) = 0.62 ± 0.04;ΦΔ(TPPOHP) = 0.73 ± 0.03;ΦΔ(TBP) = 0.76 ± 0.03;ΦΔ(TBPOHO) = 0.73 ± 0.02) using the 5,10,15,20-tetraphenyl-21,23-H-porphine (ΦΔ(TPP) = 0.66) and Phenazine (ΦΔ(Phz) = 0.83) as reference compounds. Their fluorescence quantum yields were found to be (Φf(TPPOHO) = 0.10 ± 0.04;Φf(TPPOHM) = 0.09 ± 0.03;Φf(TPPOHP) = 0.13 ± 0.02;Φf(TBP) = 0.08 ± 0.03 andΦf(TBPOHO) = 0.08 ± 0.02 using 5,10,15,20-tetraphenyl-21,23-H-porphine as referenceΦf(TPP) = 0.13). Singlet state lifetimes were also determined in the same solvent. All the porphyrins presented very similar fluorescence lifetimes (mean values ofτS(withO2, air equilibrated) = 9.6 ± 0.3 nanoseconds and (withoutO2, argon purged) = 10.1 ± 0.6 nanoseconds, resp.). The phosphorescence emission was found to be negligible for this series of unsymmetrically substituted mesoporphyrins, but an E-type, thermally activated, delayed fluorescence process was proved to occur at room temperature.

Synthesis and photophysical properties of a novel ethynyl zinc(II) phthalocyanine and its functionalized derivative with click chemistry

2013 ◽  
Vol 17 (06n07) ◽  
pp. 540-547 ◽  
Author(s):  
Altuğ Mert Sevim ◽  
İbrahim Özçeşmeci ◽  
Ahmet Gül
Keyword(s):  
Click Chemistry ◽  
Zinc Acetate ◽  
Spectroscopic Data ◽  
Photophysical Properties ◽  
Hexanoic Acid ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Elemental Analyses ◽  
New Compounds

The synthesis of novel, symmetrical zinc(II) phthalocyanine (ZnPc) bearing four ethynylcyclohexyloxy terminal moieties was achieved by cyclotetramerization of novel 4-(2-ethynylcyclohexyloxy) phthalonitrile in pentanol in the presence of DBU and zinc acetate without any protective/deprotective chemistry. Subsequently, this new zinc(II) phthalocyanine derivative was reacted with 6-azido-hexanoic acid under "click-chemistry" conditions to give phthalocyanine-hexanoic acid conjugates linked by 1,2,3-triazole units. The new compounds have been characterized by using elemental analyses, UV-vis, FTIR, 1 H NMR and mass spectroscopic data. The aggregation properties of the compounds were investigated in different concentrations. General trends are also described for fluorescence quantum yields and lifetimes of novel zinc derivatives in tetrahydrofuran. The fluorescence of the tetrasubstituted zinc(II) phthalocyanine complexes is effectively quenched by 1,4-benzoquinone (BQ) in THF.

Elaboration of an unexplored substitution site in synthetic bacteriochlorins

2015 ◽  
Vol 19 (07) ◽  
pp. 887-902 ◽  
Author(s):  
Nuonuo Zhang ◽  
Kanumuri Ramesh Reddy ◽  
Jianbing Jiang ◽  
Masahiko Taniguchi ◽  
Roger D. Sommer ◽  
...  
Keyword(s):  
Bathochromic Shift ◽  
Fluorescence Emission ◽  
Bacterial Photosynthesis ◽  
Alkoxy Group ◽  
The Self ◽  
X Ray ◽  
Long Wavelength ◽  
Substitution Site ◽  
Wavelength Absorption ◽  
Long Wavelength Absorption Band

The ability to introduce substituents at designated sites about the perimeter of synthetic bacteriochlorins – analogs of bacteriochlorophylls of bacterial photosynthesis – remains a subject of ongoing study. Here, the self-condensation of a dihydrodipyrrin-dioxolane affords a 5-[2-(trimethylsiloxy)ethoxy]bacteriochlorin. Like a 5-methoxybacteriochlorin, the latter undergoes regioselective bromination at the 15-position, directed by the distal 5-alkoxy group. On the other hand, attempted bromination of a bacteriochlorin bearing a 5-(2-hydroxyethoxy) group resulted in intramolecular ether formation with the adjacent β-pyrroline position to give an annulated dioxepine ring (confirmed by single-crystal X-ray structural analysis). The hydroxyethoxy group at the 5-position can be derivatized by acylation. In addition, the installation of auxochromes (methoxycarbonyl, phenylethynyl) at the β-pyrrole rings causes a substantial bathochromic shift of the long-wavelength absorption band (812 nm) and companion fluorescence emission band (821 nm). Taken together, the modification of the 5-substituent complements existing methods for installing a single substituent on the bacteriochlorin macrocycle.

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