Increase In Fluorescence Quantum Yield Research Articles

γ-glutamyl transpeptidase activatable NIR photosensitizer for visualization and selective killing of liver cancer cells

Photodynamic therapy (PDT) is a treatment model that involves using light sources to excite photosensitizers (PSs), generating reactive oxygen species. This method is considered a potential treatment for tumors. However, the non-selective toxicity of traditional PSs to both tumors and normal tissues hinders the advancement of PDT. This lack of selectivity is a major obstacle in the development of effective PDT. The activatable PS can only function in a specific environment, which enhances the selectivity and safety of PDT. In this paper, we focus on GGT (γ-glutamyltranspeptidase) overexpressed in liver cancer as the biological target. We designed and synthesized the activatable PS BrCy-Glu by modifying the substrate of GGT (l-glutamic acid) onto the brominated hemicyanine PS (BrCy-OH). The intramolecular charge transfer (ICT) effect of BrCy-Glu is inhibited, which leads to low fluorescence quantum yield and singlet oxygen yield. However, in the presence of GGT, it can undergo selective hydrolysis and be converted into BrCy-OH through a series of elimination reactions. This process is accompanied by a significant increase in fluorescence quantum yield and singlet oxygen yield. In vitro studies demonstrate that BrCy-Glu is suitable for precise fluorescence identification of liver cancer and selective eradication of cancer cells under light conditions.

Fluorescent Sensor Based on 1H-Pyrazolo[3,4-b]quinoline Derivative for Detecting Zn2+ Cations.

The photophysical and sensory properties of the donor-acceptor pyrazoloquinoline derivative (PQPc) were investigated using absorption, steady-state, and time-resolved fluorescence measurements. The compound synthesized from commercial, readily available substrates exhibited absorptions in the UV-Vis range, with a maximum of the longwave band around 390 nm. The maximum fluorescence was around 460-480 nm, depending on the solvent. The quantum yield was between 12.87% (for n-hexane) and 0.75% (for acetonitrile) and decreased with increasing solvent polarity. The PET mechanism was implicated as the cause of fluorescence quenching. Divalent ions such as Zn2+, Pb2+, Cd2+, Ca2+, Mg2+, Co2+, Ni2+, and Cu2+ were introduced to study the fluorescent response of PQPc. A 13-times increase in fluorescence quantum yield was observed after the addition of Zn2+ ions. Detailed research was carried out for the PQPc-Zn2+ system in order to check the possibility of analytical applications of PQPc as a fluorescent sensor. A detection limit of Zn2+ was set at the value level 1.93 × 10-7 M. PQPc-Zn2+ complexes had a stoichiometry of 1:1 with a binding constant of 859 M-1. Biological studies showed that the sensor was localized in cells near the membrane and cytoplasm and may be used to detect zinc ions in eukaryotic cells.

Substantial solubility and fluorescence property changes upon inclusion of rutaecarpine in cucurbit[7]uril: Kinetics and thermodynamics of binding

The effect of acid and cucurbit[7]uril (CB7) additions on the solubility and fluorescent properties of rutaecarpine (Rut), a pharmaceutically important plant alkaloid, was studied in aqueous solution. Approximately 550-fold water-solubility enhancement was achieved upon inclusion complex formation with CB7. The cationic protonated alkaloid (RutH+) was encapsulated in CB7 with a binding constant more than three orders of magnitude larger than that of the uncharged Rut. The stabilization of RutH+ by the host macrocycle led to a pKa increase of ∼3.3 units compared with that found in water. The substantial increase in fluorescence quantum yield upon RutH+–CB7 production could be exploited for the sensitive visualization of pH differences in the range of 4.5–6.5. The highly exothermic complexation was accompanied by considerable entropy diminution, partly because of the critical role of hydrogen bonding between the constituents. The rate constants of the creation and dissociation of RutH+–CB7 were 2.5 × 106 M−1 s−1 and 0.94 s−1 at 283 K, respectively.

Synthesis of O-B ← N embedded molecules and studies on the B ← N cleavage-driven thermo- and solvatochromic properties

Three O-B ← N embedded molecules identified as 1, 2, and 3 with different substituents and B ← N locations are synthesized to study the firmness of intramolecular B ← N coordination. After X-ray diffraction crystallography, electrochemical, and photophysical tests, in-depth B ← N cleavage-driven thermo- and solvatochromic studies were conducted. In contrast to compound 1 with phenyl side groups, compound 2 with bulky and electron-deficient perfluorophenyl substituents has twisted backbone, significantly increased fluorescence quantum yield (ΦF = 27 % vs 85 %), and most importantly, enhanced stability of B ← N coordination. Comparison to 1 and 2, whose B ← N bonds are located on the edge of fused rings, compound 3 with extended backbone conjugation and B ← N bonds embedded inside fused rings exhibits red-shifted absorption/emission, decreased ΦF = 7 %, and remarkably enhanced strength of B ← N coordination. This work discloses the effects of substituents and B ← N locations on firmness of intramolecular B ← N coordination, which are enlightening to understand the stability and application of these O-B ← N embedded molecules.

Viscosity-sensitive and AIE-active bimodal fluorescent probe for the selective detection of OCl- and Cu2+: a dual sensing approach via DFT and biological studies using green gram seeds.

A novel dual-mode viscosity-sensitive and AIE-active fluorescent chemosensor based on the naphthalene coupled pyrene (NCP) moiety was designed and synthesized for the selective detection of OCl- and Cu2+. In non-viscous media, NCP exhibited weak fluorescence; however, with an increase in viscosity using various proportions of glycerol, the fluorescence intensity was enhanced to 461 nm with a 6-fold increase in fluorescence quantum yields, which could be utilized for the quantitative determination of viscosity. Interestingly, NCP exhibited novel AIE characteristics in terms of size and growth in H2O-CH3CN mixtures with high water contents and different volume percentage of water, which was investigated using fluorescence, DLS study and SEM analysis. Interestingly, this probe can also be effectively employed as a dual-mode fluorescent probe for light up fluorescent detection of OCl- and Cu2+ at different emission wavelengths of 439 nm and 457 nm via chemodosimetric and chelation pathways, respectively. The fast-sensing ability of NCP towards OCl- was shown by a low detection limit of 0.546 μM and the binding affinity of NCP with Cu2+ was proved by a low detection limit of 3.97 μM and a high binding constant of 1.66 × 103 M-1. The sensing mechanism of NCP towards OCl- and Cu2+ was verified by UV-vis spectroscopy, fluorescence analysis, 1H-NMR analysis, mass spectroscopy, DFT study and Job plot analysis. For practical applications, the binding of NCP with OCl- and Cu2+ was determined using a dipstick method and a cell imaging study in a physiological medium using green gram seeds.

Isatin-Schiff base functionalized graphene oxide as a highly selective turn-on fluorescent probe for the detection of Pd(II) via photoinduced electron transfer pathway

We investigated the use of isatin-Schiff base functionalized graphene oxide (ISBGO) as a selective fluorescent chemosensor for the detection of palladium ions. Selectivity tests indicated that over 23 metal ions tested, ISBGO (λex = 340 nm, λem = 504 nm) showed the highest affinity for Pd(II), displaying a 10.1-fold enhancement. Also, interference tests proved that in the presence of both Pd(II) and other metal ions, there was still high fluorescence intensity and no considerable quenching occurred. According to DFT and TD-DFT calculations, photo-induced electron transfer (PET) is responsible for the turn-on response produced by the chemosensor. Coordination of Pd(II) with ISBGO in fact blocks PET from imine nitrogen of 3-iminoindolin-2-one moiety to the benzene ring, which in turn leads to a turn-on response. In addition, Job’s plot analysis and Benesi-Hildebrand approach suggest that ISBGO preferably forms a 1:1 complex with Pd(II) with an association constant of 1.020 × 105 M−1. Moreover, FT-IR spectroscopy and DFT study showed that amide oxygen and imine nitrogen of 3-iminoindolin-2-one moiety acted as binding sites of ISBGO. High sensitivity, fast response, great degree of sensitivity, short life time, low detection limit of 32 nM combined with high association constant (Kf) of 1.020 × 105 M−1 and increased fluorescence quantum yield (Φf) of roughly 1.5-fold in the presence of Pd (II), highlight the role of ISBGO as an excellent probe for sensing Pd(II) in aqueous solution.

Meso-aryltellurium-BODIPY-based fluorescence turn-on probe for selective, sensitive and fast glutathione sensing in HepG2 cells

Glutathione (GSH) as one most abundant thiol, acts as important roles in regulating cellular redox activities, and various diseases are closely related with its abnormal levels. Thus, monitoring intracellular GSH levels is essential for understanding cellular metabolism of many related diseases. In this work, we firstly reported a new fluorescence turn-on sensor, which was capable of selectively, sensitively and rapid sensing GSH over other thiols, especially cysteine and homocysteine in solutions and living cells. A meso-aryltellurium boron dipyrromethene (BODIPY) was firstly designed and synthesized, which showed silenced emission due to an efficient photoinduced electron transfer (PET) process from electron-rich Te to BODIPY, and then upon exposure to GSH, the meso-Te-C bond could be rapidly cleaved by the thiol group of GSH, thus resulting in an obvious fluorescence “turn-on” phenomenon through inhibition of the PET effect. This probe exhibited excellent selectivity and sensitivity towards GSH with a short response time of 2 min, showing a remarkable fluorescence enhancement observed at 541 nm with a large fluorescence quantum yield increase from nearly 0 to 0.73 upon excitation at 500 nm in PBS/CH3CN (9/1, v/v). The detection limit towards GSH was further calculated to be 1.7 nM by the linear fluorescence change at 541 nm in the GSH-concentration ranging from 0 to 4 μM. Furthermore, its sensing mechanism was validated by using mass spectrometry, confirming the rapid cleavage of the Te–C bond by GSH. Finally, cell imaging experiments demonstrated that this probe could successfully detect GSH in living cells, highlighting its potential for rapid and sensitive detection of intracellular GSH level changes. Therefore, a new meso-aryltellurium-BODIPY fluorescence turn-on sensor was firstly developed, which could selectively, sensitively and fast detect cellular GSH over other thiols based on the rapid cleavage of the meso Te–C bond.

Increasing the Fluorescence Quantum Yield and Lifetime of the Flavin Chromophore by Rational Design

AbstractA previous quantum chemical study (M. Bracker et al., Phys. Chem. Chem. Phys. 2019, 21, 9912–9923) on the excited state properties of fluorinated derivatives of the flavin chromophore promised an increased fluorescence performance of the derivative 7,8‐difluoro‐10‐methyl‐isoalloxazine (7,8‐dF‐MIA). Here, we describe the synthesis of 7,8‐dF‐MIA, its ribityl derivative, and for reason of comparison 9‐F‐MIA. The compounds dissolved in water (H2O and D2O) were characterized by steady state, time resolved, and fluorescence correlation spectroscopy. The experiments confirm the increase of the fluorescence quantum yield of 7,8‐dF‐MIA (0.42 in H2O) compared to MIA (0.22) predicted by quantum chemistry. The anticipated reduction of the fluorescence quantum yield for 9‐F‐MIA is also confirmed experimentally. The quantum chemical computations as well as the spectroscopic observations attribute the increased fluorescence quantum yield of 7,8‐dF‐MIA predominantly to a decrease of the rate constant of intersystem crossing. Switching from H2O to D2O as a solvent is shown to increase fluorescence quantum yields (0.53 for 7,8‐dF‐MIA) and lifetimes of all fluorinated MIA derivatives. This can be attributed to a Förster type energy transfer from the excited chromophore to vibrational overtones of water and further water‐mediated deactivation processes.

Exploring the Effects of Mutagenesis on FusionRed by Using Excited-State QM/MM Dynamics and Classical Force Field Simulations.

Fluorescent proteins (FPs) are a powerful tool for examining tissues, cells, and subcellular components in vivo and in vitro. FusionRed is a particular FP variant mutated from mKate2 that, in addition to lower cytotoxicity and aggregation rates, has shown potential for acting as a tunable photoswitch. This was posited to stem partially from the presence of a bulky side chain at position 158 and a further stabilizing residue at position 157. In this work, we apply computational techniques including classical molecular dynamics (MD) and combined quantum mechanics/molecular mechanics simulations (QM/MM) to explore the effect of mutagenesis at these locations in FusionRed on the chromophore structure, the excited-state surface, and relative positional stability of the chromophore in the protein pocket. We find specific connections between the statistical sampling of the underlying protein structure and the nonradiative decay mechanisms from excited-state dynamics. A single mutation (C158I) that restricts the motion of the chromophore through a favorable hydrophobic interaction corresponds to an increase in fluorescence quantum yield (FQY), while a second rescue mutation (C158I-A157N) partially restores the flexibility of the chromophore and photoswitchability with favorable water interactions on the surface of the protein that counteracts the original interaction. We suggest that applying this understanding of structural features that inhibit or favor rotation on the excited state can be applied for rational design of new, tunable and red photoswitches.

Regulation of fluorescent color and efficiency by molecular symmetry engineering of triphenylamine-based red emitters and their applications

Fine tuning the energy gaps of red emitters and promoting the fluorescence efficiencies are especially highly desired considering their specific applications. Herein, by varying the molecular symmetry from D-A-D to D-A structures, the red fluorescent emitters with triphenylamine (TPA) donor and 2,3-dicyanopyrazino phenanthrene (DCPP) acceptor realized increased fluorescence quantum yield (ΦPL) from 2TPA-DCPP to TPA-DCPP due to the decreased non-radiative paths. Moreover, fine control of the emitting color from orange to red and then to deep-red was achieved depending on the intermolecular packing patterns of TPA-DCPP in the aggregation state. Taking the advantages, TPA-DCPP-based OLED exhibited red emission (λ = 640 nm, CIE coordinate of (0.62, 0.38)) with an excellent maximum EQE of 8.30%. The TPA-DCPP@F-127 nanoparticles showed deep-red emission (λ = 684 nm) and were successfully used for cellular imaging of Hela cells. Our results demonstrated that “the simpler, the better” strategy may be feasible to construct D-A structured red emitters with high efficiencies for diverse applications.

Conformational Dynamics of mCherry Variants: A Link between Side-Chain Motions and Fluorescence Brightness.

The 3-fold higher brightness of the recently developed mCherry-XL red fluorescent protein (FP) compared to its progenitor, mCherry, is due to a significant decrease in the nonradiative decay rate underlying its increased fluorescence quantum yield. To examine the structural and dynamic role of the four mutations that distinguish the two FPs and closely related variants, we employed microsecond time scale, all-atom molecular dynamics simulations. The simulations revealed that the I197R mutation leads to the formation of multiple hydrogen-bonded contacts and increased rigidity of the β-barrel. In particular, mCherryXL showed reduced nanosecond time scale breathing of the gap between the β7 and β10-strands, which was previously shown to be the most flexible region of mCherry. Together with experimental results, the simulations also reveal steric interactions of residue 161 and a network of hydrogen-bonding interactions of the chromophore with residues at positions 59, 143, and 163 that are critical in perturbing the chromophore electronic structure. Finally, we shed light on the conformational dynamics of the conserved residues R95 and S146, which are hydrogen-bonded to the chromophore, and provide physical insights into the observed photophysics. To the best of our knowledge, this is the first study that evaluates the conformational space for a set of closely related FPs generated by directed evolution.

Modification of optical properties in helicenes via construction of phosphine oxide-based push-pull systems

Six [6]helicene based push-pull systems combining three diarylamines as donors and two phosphine-oxides as acceptors were designed and synthesized in order to modify optical properties of the helicene skeleton. The properties of the target compounds were studied by DFT calculations and spectroscopic methods in both solution and solid film and compared to those of purposely synthesized reference compounds. It was found that the optical properties change substantially upon formation of the push-pull system and show dependence on the withdrawing ability of the acceptor. Furthermore, the introduction of the diphenylaminophenylene group as a donor led to significant increase of fluorescence quantum yield and also a significant dependence of the fluorescence maxima on the polarity of solvent – solvatochromism. The Lippert-Mataga plots were used to estimate the change in dipole moments (Δμ).

Fluorescent property of carbon dots extracted from cigarette smoke and the application in bio-imaging.

Cigarette smoke is one of the six major pollution sources in the room air. It contains large number of particles with size less than 10 nm. There exist carbon dots (CDs) in cigarette smoke which have strong fluorescence and with good bio-compatibility and low toxicity. CDs in cigarette smoke can be applied in bio-imaging which has great potential applications in the integration of cancer diagnosis and treatment. In this paper, CDs were extracted from cigarette smoke. Then, sodium borohydride was added to CDs aqueous solution for reduction and the reduced CDs (R-CDs) were used for biological cell imaging. The results indicate that the CDs with the particle size <10 nm in cigarette smoke are self-assembled by the polymerizated polycyclic aromatic hydrocarbons (PAHs) and ammonium nitrite which are disk nano-structure composed of sp2/sp3 carbon and oxygen/nitrogen groups or polymers. Sodium borohydride can reduce the carbonyl group on the surface of CDs to hydroxyl group and increase the ratio of the Na 1s ratio of the CDs from 1.86 to 7.42. The CDs can emit blue fluorescence under ultraviolet irradiation. After reduction, the R-CDS have the intensity of fluorescence 7.2 times than before and the fluorescence quantum yield increase from 6.13% to 8.86%. The photoluminescence (PL) wavelength of R-CDS have red-shift of 7 nm which was due to the increasing of Na element ratio. The onion epidermal cells labeled with R-CDs show that the CDs could pass through the cell wall into the cell and reach the nucleus. The cell wall and the nucleus could be clearly visualized. CDs also shows low toxicity to human bronchial epithelial cells (BEAS-2B) with good biological activity. The obtained results indicate that the CDs and R-CDs have good fluorescent property which could be used as bio-imaging agent.

On the fluorescence enhancement of arch neuronal optogenetic reporters

The lack of a theory capable of connecting the amino acid sequence of a light-absorbing protein with its fluorescence brightness is hampering the development of tools for understanding neuronal communications. Here we demonstrate that a theory can be established by constructing quantum chemical models of a set of Archaerhodopsin reporters in their electronically excited state. We found that the experimentally observed increase in fluorescence quantum yield is proportional to the computed decrease in energy difference between the fluorescent state and a nearby photoisomerization channel leading to an exotic diradical of the protein chromophore. This finding will ultimately support the development of technologies for searching novel fluorescent rhodopsin variants and unveil electrostatic changes that make light emission brighter and brighter.

Synthesis, Optical Properties, Preliminary Antimycobacterial Evaluation and Docking Studies of Trifluoroacetylated 3‐Pyrrolyl Boron‐Dipyrromethene

AbstractThe article provides the route to trifluoroacetylated fluorescent boron dipyrromethene dye (2). The compound performs intensive absorption and emission bands in near‐red wavelength region. Photophysical properties of 2 are investigated in different solvents. A notable increase of fluorescence quantum yield after trifluoroacetyl group insertion connected with a change in intramolecular interactions parameters. The role of molecular geometry aspects in observed photophysical properties and molecular fragments rotation energy barriers are explained by quantum‐mechanical calculations. 2 performs considerable antimycobacterial activity. According to molecular docking simulations, 2 is capable of affinity binding in the active sites of mycobacterial MycP1 and MycP3 serine proteases. The geometries of final ligand‐protein complexes show the possibility of protein active site covalent modification at the serine residue of the catalytic triad. At lower concentrations, 2 can act as a fluorescent dye for microscopy analysis and corresponding staining patterns are shown for Mycobacterium smegmatis and Staphylococcus aureus cells.

Conformational fixation induced fluorescence turn-on of oxytetracycline coordinated on aluminum-based metal-organic frameworks for ultrasensitive sensing application

Since the abuse of oxytetracycline (OTC) has brought serious environmental problems, it is of great practical significance to develop sensitive OTC fluorescent probes to quantify environmental OTC residues. Herein, the aluminum-based metal-organic framework MIL-53(Al) with microflower morphology and plentiful surface open aluminum sites (denoted as FMIL-53(Al)) was tailored via an acetic acid-assisted solvothermal method and subsequently exploited for ultrasensitive detection of OTC. Compared with conventional hydrothermally synthesized MIL-53(Al), FMIL-53(Al) possesses a larger specific surface with plentiful open aluminum sites, which can selectively coordinate with OTC to fix the molecular conformation. The coordinated OTC molecules undergo a transition from twisted-conformation to extended-conformation, accompanied by an increase in fluorescence quantum yield. As a fluorescent probe, the detection limit of FMIL-53(Al) for OTC is estimated as low as 0.94 nM. Finally, the FMIL-53(Al)-based probe can be applied for the detection of OTC in water samples of fish farm pond, and a portable test paper was successfully fabricated for on-site visual identification of OTC. This work not only demonstrates a novel morphology of MIL-53(Al) for OTC ultrasensitive sensing but also provides an example of morphological engineering to optimize the performance of MOF-based fluorescence sensors.

Intermolecular hydrogen-bonding-induced fluorescence of 3-hydroxyisonicotinealdehyde in different pH media

In this contribution, we have attempted to solve the challenges in theoretically predicting the photophysical properties of 3-hydroxyisonicotinealdehyde in different pH media. Our calculations results demonstrated that in acidic and neutral conditions, the intermolecular hydrogen bonding (Inter-HB) will increase the energy of the dark nπ* state and inhibit the occurrence of excited-state intramolecular proton transfer (ESIPT), leading to emission from the enol form. In alkaline conditions, the existence of phenolate makes the absence of the ESIPT process. Moreover, the strength of Inter-HB between oxyanion and water increases significantly and the formed complex plays an important role in the emission spectra. The increase in fluorescence quantum yield with increasing pH was found to be correlated with the energy difference between nπ* and ππ* states. Our study not only reveals the multiple roles of Inter-HB in inducing the fluorescence of 3-hydroxyisonicotinealdehyde, but also provides theoretical guides for further development of new fluorophores with intense emission in water.

Synthesis of Substituted Cy5 Phosphoramidite Derivatives and Their Incorporation into Oligonucleotides Using Automated DNA Synthesis.

Cyanine dyes represent a family of organic fluorophores with widespread utility in biological-based applications ranging from real-time PCR probes to protein labeling. One burgeoning use currently being explored with indodicarbocyanine (Cy5) in particular is that of accessing exciton delocalization in designer DNA dye aggregate structures for potential development of light-harvesting devices and room-temperature quantum computers. Tuning the hydrophilicity/hydrophobicity of Cy5 dyes in such DNA structures should influence the strength of their excitonic coupling; however, the requisite commercial Cy5 derivatives available for direct incorporation into DNA are nonexistent. Here, we prepare a series of Cy5 derivatives that possess different 5,5′-substituents and detail their incorporation into a set of DNA sequences. In addition to varying dye hydrophobicity/hydrophilicity, the 5,5′-substituents, including hexyloxy, triethyleneglycol monomethyl ether, tert-butyl, and chloro groups were chosen so as to vary the inherent electron-donating/withdrawing character while also tuning their resulting absorption and emission properties. Following the synthesis of parent dyes, one of their pendant alkyl chains was functionalized with a monomethoxytrityl protective group with the remaining hydroxyl-terminated N-propyl linker permitting rapid, same-day phosphoramidite conversion and direct internal DNA incorporation into nascent oligonucleotides with moderate to good yields using a 1 μmole scale automated DNA synthesis. Labeled sequences were cleaved from the controlled pore glass matrix, purified by HPLC, and their photophysical properties were characterized. The DNA-labeled Cy5 derivatives displayed spectroscopic properties that paralleled the parent dyes, with either no change or an increase in fluorescence quantum yield depending upon sequence.

Photobase-Driven Excited-State Intramolecular Proton Transfer (ESIPT) in a Strapped π-Electron System.

We report a new design strategy for an excited-state intramolecular proton transfer (ESIPT) fluorophore that can be used in acidic media. A photobasic pyridine-centered donor-acceptor-donor-type fluorophore is combined with a basic trialkylamine "strap". In the presence of an acid, protonation occurs predominantly at the amine moiety in the ground state. A single-crystal X-ray diffraction analysis confirmed the formation of a pre-organized intramolecular hydrogen-bonded structure between the resulting ammonium moiety and the pyridine ring. Upon excitation, the intramolecular charge-transfer transition increases the basicity of the pyridine moiety in the excited state, resulting in proton transfer from the amine to the pyridine moiety. Consequently, the fluorophore takes on a polymethine-dye character in the ESIPT state, which gives rise to significantly red-shifted emission with an increased fluorescence quantum yield.

Electronic Structure and Excited-State Dynamics of Rylene-Tetrapyrrole Panchromatic Absorbers.

Panchromatic absorbers have potential applications in molecular-based energy-conversion schemes. A prior porphyrin-perylene dyad (P-PMI, where "MI" denotes monoimide) coupled via an ethyne linker exhibits panchromatic absorption (350-700 nm) and a tetrapyrrole-like lowest singlet excited state with a relatively long singlet excited-state lifetime (τS) and increased fluorescence quantum yield (Φf) versus the parent porphyrin. To explore the extension of panchromaticity to longer wavelengths, three arrays have been synthesized: a chlorin-terrylene dyad (C-TMI), a bacteriochlorin-terrylene dyad (B-TMI), and a perylene-porphyrin-terrylene triad (PMI-P-TMI), where the terrylene, a π-extended homologue of perylene, is attached via an ethyne linker. Characterization of the spectra (absorption and fluorescence), excited-state properties (lifetime, yields, and rate constants of decay pathways), and molecular-orbital characteristics reveals unexpected subtleties. The wavelength of the red-region absorption band increases in the order C-TMI (705 nm) < PMI-P-TMI (749 nm) < B-TMI (774 nm), yet each array exhibits diminished Φf and shortened τS values. The PMI-P-TMI triad in toluene exhibits Φf = 0.038 and τS = 139 ps versus the all-perylene triad (PMI-P-PMI) for which Φf = 0.26 and τS = 2000 ps. The results highlight design constraints for auxiliary pigments with tetrapyrroles to achieve panchromatic absorption with retention of viable excited-state properties.