Lifetime Studies Research Articles

Humic fractions from Amazon soils: Lifetime study and humification process by fluorescence spectroscopy

The Amazon Forest is an important and primordial ecosystem, as it controls the dynamics of soil organic matter (SOM) and is considered one of the crucial carbon reservoirs in the world. Based on that, this study evaluated the molecular properties of humic (HA) and fulvic (FA) acid from Amazon soil, with and without Cu(II) ions, by Time-Resolved Laser Fluorescence Spectroscopy (TRLFS) and Fluorescence Spectroscopy (FS). Fluorescence excitation-emission matrix (EEM) was obtained by FS, and EEM spectra were treated by canonical polyadic/parallel factor analysis (EEM-CP/PARAFAC). The results showed that the humification index (A465nm) determined by FS is directly dependent on fluorophores’ CII/CI ratio in these soils with depth (r = 0.89), especially for HA samples in deep horizons, which demonstrated that the CII consists more complex and humified structure of the SOM. The lifetime decay showed the presence of static quenching in the humic fractions. From the lifetime data provided by TRLFS and the different correlations with carbon content and A465nm, it can be suggested that the fluorescence suppression modifies the molecular properties of the humic fractions with the addition of Cu(II) ions, such as altering the mobility and availability of the metal in the complexation reactions in these Amazonian Spodosols, mainly for the fulvic fraction.

Atomic-structure investigations of neutral einsteinium by laser resonance ionization

Excited atomic states of neutral einsteinium were investigated by resonant laser ionization using 10 pg $(2\ifmmode\times\else\texttimes\fi{}{10}^{10}$ atoms) of $^{254}\mathrm{Es}$. Ten transitions from the ${5f}^{11}7s{}^{2}^{4}I_{15/2}^{o}$ ground state to even-parity states were investigated in detail, via studies of lifetimes and further excitation steps into higher-lying odd-parity states below and above the first ionization potential. This led to the identification of 37 previously unknown odd-parity energy levels in the region between $37\phantom{\rule{0.16em}{0ex}}000$ and $42\phantom{\rule{0.16em}{0ex}}500\phantom{\rule{0.16em}{0ex}}\mathrm{cm}{}^{\ensuremath{-}1}$ and a number of autoionizing states, which ensure a high ion yield in resonant ionization. Rydberg states were identified and the corresponding Rydberg series converging either to the ionic ground or an excited state were analyzed to determine the first ionization potential of einsteinium to a value of ${E}_{\text{IP}}=51\phantom{\rule{0.16em}{0ex}}364.58{(14)}_{\mathrm{stat}}{(50)}_{\mathrm{sys}}\phantom{\rule{0.16em}{0ex}}\mathrm{cm}{}^{\ensuremath{-}1}$, improving the previous result by a factor of four.

Increased Drug‐Loading Enhances the Activity of Ellipticine in Poly(N‐(2‐hydroxypropyl) Methacrylamide) PHPMA‐Based Polymeric Micelles in 2D and 3D Cancer Cell Models

AbstractPolymeric micelles are widely used as multifunctional drug carriers of poorly water‐soluble drugs, but the role of drug loading content is often overlooked. The purpose of this study is to investigate the cellular uptake and penetration of polymeric micelles with different drug loading contents and their effects on biological activities. In this study, poly(N‐(2‐hydroxypropyl) methacrylamide‐co‐methacrylic acid)‐block‐poly methyl methacrylate P(HPMA‐co‐MAA)‐b‐PMMA micelles are used as a nanocarrier for the encapsulation of the potent anticancer agent ellipticine (EPT). The micelles are loaded with various amounts of EPT and the physicochemical characteristics such as particle size, morphology, and zeta potential of blank and EPT loaded nanoparticles are studied. Moreover, fluorescent lifetime studies confirm that hydrophobic EPT is indeed in the PMMA micelle core. In vitro cytotoxicity tests using the glioma cell line U87MG reveal lower IC50 values when the cells are incubated with micelle with high drug loading content. The higher toxicity in micelles with higher drug loading content is associated with higher cellular uptake, which is monitored using laser scanning confocal microscopy and flow cytometry. Moreover, higher activity of micelles with higher drug loading is also observed in U87MG multicellular tumor spheroids although the difference is not significant.

The ϕ-divergence family of measures based on quantile function

The quantile function can be considered an efficient alternative to the distribution function in cases where the quantile functions are tractable while the distribution functions do not have explicit forms. In this paper, we introduce a quantile-based definition of the ϕ-divergence family of measures to assess the discrepancy between two random variables. The proposed measure defines a rich family of divergence measures and includes various common divergences as special cases. Some properties of these measures of divergence are studied and several examples are also provided. Dynamic versions of the quantile-based ϕ-divergence family of measures between residual and past lifetimes are developed and their properties are studied. The suggested divergence measures are also examined in a general class of transformed models which results in some well-known models in the lifetime studies and survival analysis. Furthermore, the non-parametric estimations of the proposed divergence measures are discussed, and the performance of the resulting estimators is evaluated via simulation.

2D Metal‐Organic Framework Based on the Functionalized Anthracene Derivative as A Dual‐Functional Luminescent Probe for Fe3+ and Ascorbic Acid

AbstractTwo‐dimensional (2D) materials are newly developed for their thickness‐dependent physical and chemical properties. The major characteristic of this type of material is that the planar structure flaunts a large surface‐to‐volume ratio, thereby providing a platform for straightforward and easy functionalization with chemical moieties, which prompting us to use it as a chemical sensor. We designed and synthesized two types of 2D metal‐organic frameworks based on the functionalized anthracene derivative 4,4′‐(anthracene‐9,10‐diylbis(ethyne‐2,1‐diyl))dibenzoic acid (H2L), [Pb(L)(DMF)] (denoted as Pb‐MOF) and [Sm(L)(HCO2)(DMF)] (denoted as Sm‐MOF). These two materials are great sensors for probing Fe3+ and ascorbic acid (AA) with the low concentration according to “color‐change recover” effect. Fe3+ was captured by MOF and this quenching mechanism was investigated using luminescence, UV‐vis, XPS, and lifetime studies.

Environmental exposures and lymphoma risk: a nested case–control study using the Golden Retriever Lifetime Study cohort

Lymphoma is the second most common cancer affecting Golden Retrievers and is hypothesized to arise through a complex interaction of genetic and environmental factors. The aim of this nested case–control study was to investigate the association between potential environmental pollutant sources and lymphoma risk among Golden Retrievers participating in the Golden Retriever Lifetime Study. Forty-nine Golden Retrievers with non-cutaneous lymphoma and 98 Golden Retrievers without a history of cancer matched by age, sex and neuter status were selected from the Golden Retriever Lifetime Study cohort. Geographic proximity between each dog’s primary residence and nine potential sources of environmental pollution was determined. In addition, the average annual ozone and airborne fine particulate matter levels for each dog’s county of residence and owner-reported secondhand smoke exposure were evaluated. Environmental pollution sources of interest included chemical plants, municipal dumps, manufacturing plants, incineration plants, railroad embankment tracks, landfills, coal plants, high-voltage transmission lines, and nuclear power plants. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each exposure of interest. Subgroup analyses were conducted to evaluate whether associations differed among 1) dogs with multicentric lymphoma, 2) dogs with B-cell lymphoma, and 3) dogs with T-cell lymphoma. No variables reached statistical significance when evaluating all cases together. However, cumulative exposure burden (household proximity to 3 or more pollution sources) approached significance within the multicentric lymphoma subgroup (OR = 2.60, 95%CI 0.99–6.86, p-value = 0.053). Patterns emerged among B- and T-cell subgroups, but none reached statistical significance. Ongoing research is warranted to discern if different environmental mechanisms may be driving B- and T-cell lymphoma immunophenotypes, consistent with previously reported regional differences in subtype prevalence.

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

AbstractColloidal quantum dot‐based light‐emitting diodes (QD‐LEDs) are one of the potential future self‐emissive displays owing to their large‐scale solution‐processibility and high color purity. For the industrial application of QD‐LEDs, high‐performance QD‐LED and high‐resolution patterning of quantum dot (QD) films are required. Photolithography is an ideal tool for patterning QD films. Previously, the high‐resolution patterning of QD films using direct photolithography by ultra‐thin atomic layer deposition of ZnO on the QD surface is reported. The patterning process is acceptable for Cd‐based QD films, but the photoresist severely deteriorates the photoluminescence (PL) intensity of InP‐based QD films owing to the presence of sulfonic groups in the photoactive compound. Herein, a non‐destructive direct photolithography process for QD film patterning using a negative photoresist that does not affect the PL intensities of Cd‐ and InP‐based QD films is reported. The effect of the photoresist is also verified by a PL lifetime study. Extremely bright Cd‐ and InP‐based QD films are successfully patterned using a softer photoresist, and micropatterning of InP‐based QD films is reported for the first time in this work using photolithography. A QD electroluminescence device is also successfully fabricated using the patterning method.

Crystal structure, molecular structural analysis, optical absorption and thermal analysis of 2-amino-6-methyl pyridine-1-ium 2-carboxy-6-nitro benzoate – A third harmonic nonlinear optical organic single crystal

Single crystals of the newly concocted 2-amino-6-methyl pyridine-1-ium 2-carboxy-6-nitro benzoate (MPNP) were grown by slow evaporation approach using an equimolar ethanol-water mixed solvent. The crystal structure of MPNP with the single-crystal X-ray diffraction technique revealed a centrosymmetric triclinic molecular arrangement. A robust hydrogen bond network with a cloud of supramolecular assemblies, S (4), S (8), S (10) and S (11), ring graph set motifs, R22 (8), R44 (18) and R (10) and π – π linkages establish molecular packing. Hirshfeld surface analysis substantiated non-bonded interactions in the structure. Experimental FT-IR and Raman vibration modes were analyzed in order to establish the presence of functional groups and the amine-imine tautomeric form. Molecular structure confirmation was corroborated with experimental NMR spectra. UV–Visible spectral profiling with Tauc, Urbach, and dispersion plots for refractive index variations were performed to understand the origin of optical band in the material. TCSPC lifetime studies envisaged the immense scintillating efficacy of MPNP. The experimental Z-scan data of MPNP in the closed and open aperture modes were deployed to estimate the magnitude of the nonlinear optical properties of MPNP, thereby establishing a good scope for optical applications. Thermogravimetry coupled with Differential Scanning Calorimetry (DSC) declares high thermal stability of the material till 177.6 °C.

Photoluminescence Quenching in Recyclable Water-Soluble Zn-Based Metal–Organic Framework Nanoflakes for Dichromate Sensing

Nanoflakes are materials with high dispersion, a large specific surface area, and a high number of active sites that can provide a good platform for various fluorescence sensors and are very popular among researchers. In this study, a nanoflake-like zinc metal–organic framework (Zn-MOF) was successfully synthesized from the organic ligand 1,2,4,5-tetra(1H-imidazol-1-yl)benzene and zinc nitrate. The synthesized Zn-MOF nanoflakes are extremely soluble in water and exhibit high fluorescence stability. Since Cr2O72– can significantly quench the fluorescence of Zn-MOF aqueous solution, a rapid detection method for Cr2O72– content in water was constructed with a linear range and linear correlation of 0.3–20 μM and 0.992, respectively. The fluorescence quenching constant of the Zn-MOF is KSV = 2.003 × 104 M–1, and the detection limit for Cr2O72– is as low as 0.09 μM. Through the study of fluorescence lifetime and UV absorption, it is proven that the mechanism of Cr2O72– quenching the fluorescence of the Zn-MOF is the inner filter effect. In addition, even after being applied five times, the Zn-MOF still maintained good detection performance for Cr2O72–. The proposed method was successfully applied to the determination of real water samples, confirming that it can be used as an alternative method for the detection of Cr2O72– in environmental samples.

A simulation based incremental study of stable perovskite-on-perovskite tandem solar device utilizing non-toxic tin and germanium perovskite

In this investigation, solar cell capacitance simulator (SCAPS) was utilized to numerically analyse an all-tandem solar cell device with non-toxic Methyl-ammonium lead iodide, MAGeI3, as the top cell and Methyl-ammonium tin iodide, MASnI3, as the bottom cell. Prior to numerically simulating the tandem structure, single-junction MAGeI3 and MASnI3 were optimized through investigations of series resistance, bulk defect density, back contact metal (BCM) and choice of electron transport layer (ETL) and hole transport layer (HTL) materials. TiO2, PCBM, SnO2 and ZnO were investigated as ETL candidates while Cu2O, Spiro-OMETAD, PEDOT: PSS, p3HT, CuSCN, CuI, and CuSbS2 were probed as HTL options. Validation studies for MASnI3 were conducted against experimental J-V characteristic parameters, revealing high congruence; a single junction device power conversion efficiency (PCE) value of 6.67% for MASnI3 was established. Additionally, numerically predicted value for single-junction MAGeI3 boasts a PCE of 18.69%, showing robust similarity with previous numerical investigations. The overall single-junction device optimizations highlighted a PCE improvement from 6.67% to 16.46% for single-junction MASnI3 and 18.17–22.73% for single-junction MAGeI3. Device stability was analysed using studies of diffusion length and carrier lifetime. Numerical simulation results demonstrate that the 2-T configuration of MAGeI3-on-MASnI3 output an overall PCE of 19.11%, while the 4-T configuration boasts a high value of 31.01%. Further analysis of device susceptibility at high temperature has been conducted and it indicates temperature increase from 300 K to 375 K decreases PCE from 31.01% to 27.84% (for 4-T) and 18.56–16.14% (for 2-T). In all, the current investigation highlights remarkable potential for the all-perovskite tandem MAGeI3-on-MASnI3 solar device as an economic and non-toxic alternative to traditional Si-based solar devices.

Effect of Hydrogen Bonding on the Luminescence Lifetime and Device Resistance: A Case Study Based on Two New Related Cd-Based Coordination Polymers

Two new coordination polymers of formulas [Cd2(2,3-pzdc)(tz)2] (1) and [Cd2(2,3-pzdc)(dtz)2] (2) {2,3-pzdc = 2,3-pyrazine dicarboxylate, tz = 1,2,4-triazolate, dtz = 3,5-diamino-1,2,4-triazolate)} were synthesized via hydrothermal techniques. Both the compounds were characterized by single-crystal X-ray analysis, powder X-ray diffraction, Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA). Single-crystal X-ray analysis shows that both the structures are three-dimensional in nature and connectivity-wise they are similar to each other. In compound 2, the presence of N–H···O hydrogen-bond interactions further stabilized the structure. Aqueous dispersion of both the compounds showed a strong dual emission─one at around 353 nm and another at 369 nm upon excitation at 280 nm. Lifetime studies from time-resolved spectra show 0.82 and 0.60 ns for compound 1 and 2.02 and 1.78 ns for compound 2. The higher lifetimes of the excited states in the case of compound 2 establish the role of hydrogen-bond interactions in reducing the nonradiative decay processes. To explore the junction properties at the Al/material interface of these Schottky barrier diodes, the dark J–V characteristics of both of the devices (ITO/PEDOT/compound 1/Al and ITO/PEDOT/compound 2/Al) were analyzed using the well-known Shockley diode equation. In both the devices (with compound 1 and compound 2), asymmetric behavior is observed under forward and reverse bias, indicating rectification. However, in the compound 2 device, the overall current magnitude is 10 times higher than that of the compound 1 device. The series resistance extracted for the compound 2 device is ≈ 22 times lower than that of the compound 1 device, indicating the higher conductivity of compound 2. This behavior indicates a probable role of hydrogen-bond interactions in the lower resistance and higher conductivity of compound 2 compared to compound 1.

Positron annihilation lifetime study of subnano level free volume features of grafted polymer electrolyte membranes for hydrogen fuel cell applications

AbstractThe subnano level free‐volume hole features of poly(styrene sulfonic acid) (PSSA) grafted poly(ethylene‐co‐tetrafluoroethylene) polymer electrolyte membranes (ETFE‐PEMs) are investigated using positron annihilation lifetime spectroscopy (PALS). The hole sizes are formed mainly at the graft‐polymerization step and are not altered dramatically at the sulfonation. With increasing grafting degree, τ4, standing for the annihilation of ortho‐positronium (o‐Ps) in the larger free‐volume holes of the mobile amorphous layers and the PSSA grafts outside of the lamellae, decreases monotonously, whereas τ3, representing for that in the smaller free‐volume holes of the lamellar amorphous regions, the PSSA grafts, and the interface zones inside the lamellae, only shows a slight decrease. From the viewpoint of free‐volume hole sizes, gas molecules are predicted to pass dominantly through the mobile amorphous phases and the PSSA grafts outside of the lamellae. Specifically, the limited hole concentration induced by confining lamellae at the interfacial zones is observed. Thus, the obtained results are associated with a significant reduction of gas passing and the moderate or higher tensile strength for the ETFE‐PEMs in comparison to Nafion‐212.

Cohort profile: The Golden Retriever Lifetime Study (GRLS).

The aim of this article is to provide a detailed description of the Golden Retriever Lifetime Study (GRLS), a prospective cohort study investigating nutritional, environmental, lifestyle, and genetic risk factors for cancer and other common diseases in dogs. Primary outcomes of interest include hemangiosarcoma, lymphoma, osteosarcoma, and high-grade mast cell tumors. Secondary outcomes of interest include other cancers, hypothyroidism, epilepsy, atopy, otitis externa, hip dysplasia, heart failure, and renal failure. A total of 3,044 United States Golden Retrievers aged 6 months to 2 years completed baseline enrollment from June 2012 to April 2015. As of May 31, 2021, 2,251 dogs remain engaged in the study, 352 have died, and 441 are lost to follow-up. Extensive annual questionnaires completed by owners and veterinarians gather information about lifestyle, environmental exposures, physical activity, reproductive history, behavior, diet, medications, and diagnoses. Dogs also have annual veterinary examinations and biospecimen collection (blood, serum, hair, nails, feces, urine) for biobanking. Additional reporting, including histology and tumor biobanking, is conducted for any malignancies or deaths. When an animal dies, full medical records are obtained, and necropsies are requested at owner discretion. Full or partial necropsies have been performed on 218 dogs. Questionnaire data are freely available to researchers with approved credentials who agree to a data use agreement. In addition, researchers can submit proposals to utilize biospecimens or obtain additional data.

Phone Camera Nano-Biosensor Using Mighty Sensitive Transparent Reusable Upconversion Paper.

Lycopene, a natural colorant and antioxidant with a huge growing market, is highly susceptible to photo/thermal degradation, which demands real-time sensors. Hence, here a transparent upconversion nanoparticles (UCNPs) strip having 30 mol % Yb, 0.1 mol % Tm, and β-NaYF4 UCNPs, which shows an intense emission at 475 nm, has been developed. This strip has been found to be sensitive to lycopene with a detection limit as low as 10 nM using a smartphone camera, which is due to static quenching that is confirmed by the lifetime study. In comparison to previous paper strips, here the transparent strip has minimal scattering with maximum sensitivity in spite of not using any metal quenchers. An increase in strip hydrophobicity during the fabrication process complements the strip to selectively permeate and present an extraction-free substitute analysis for chromatography. Hydrophobicity endows the strip with the capability to reuse the strip with ∼100% luminescence recovery.

Corrosion of Transparent Electrodes Study

Abstract This work reports a study of corrosion lifetime of transparent electrodes deposited on the microscopic glass substrate. A procedure was developed for obtaining the transparent electrode by spray method. The corrosion lifetime variation in the presence of 1.5 M NaOH medium chemically degraded at room temperature before and after gamma irradiation was determined by measuring the evolution of the structure, electrical and optical characteristics. The mean values of transmittance up to 25 month before and after irradiation were calculated 91% ±6% and 96±7%, respectively. The average value of resistivity after corrosion and age time after γ-irradiation was 0.016±9% Ω.cm and 0.017± 4% at 1.0 kHz. No significant changes observed for 27 hr corrosion and 25 month age time of the transparent electrodes in NaOH solution.

Photophysical Behaviour of Novel Quaternary Pyrenoyl Salts and Their Sensitivity Towards Bile Salt Micellization.

The present work describes the synthesis and characterization of pyrene derivatives, N-(1-Pyrenoylmethyl) pyridinium bromide (PM-PB) and N-(1-Pyrenoylmethyl)-N,N,N-triethylammonium bromide (PM-TAB). The photophysical behavior of these molecules has been studied in various protic and aprotic solvents. Using steady state fluorescence intensity, fluorescence anisotropy and dynamic fluorescence lifetime studies, the sensitivity of these molecules towards the micellization process of bile salts has been monitored. These derivatives have been effectively used in estimating critical micellar concentration (CMC) of bile salt, sodium deoxycholate (NaDC).

A general multivariate lifetime model with a multivariate additive process as conditional hazard rate increment process

The object of the present paper is the study of the joint lifetime of d components subject to a common stressful external environment. Out of the stressing environment, the components are independent and the lifetime of each component is characterized by its failure (hazard) rate function. The impact of the external environment is modelled through an increase in the individual failure rates of the components. The failure rate increments due to the environment increase over time and they are dependent among components. The evolution of the joint failure rate increments is modelled by a non negative multivariate additive process, which include Lévy processes and non-homogeneous compound Poisson processes, hence encompassing several models from the previous literature. A full form expression is provided for the multivariate survival function with respect to the intensity measure of a general additive process, using the construction of an additive process from a Poisson random measure (or Poisson point process). The results are next specialized to Lévy processes and other additive processes (time-scaled Lévy processes, extended Lévy processes and shock models), thus providing simple and easily computable expressions. All results are provided under the assumption that the additive process has bounded variations, but it is possible to relax this assumption by means of approximation procedures, as is shown for the last model of this paper.

Development of moderately fluorescence active salen type chemosensor for judicious recognition and quantification of Zn(II), Al(III) and SO4=: Demonstration of molecular logic gate formation and live cell images studies

A Salen type Schiff base H3L, generated by the one step condensation of 1, 3 diamino 2-propanol and 3- ethoxy salicylaldehyde, for selective and easy detection of the two different cations Zn(II), Al(III) and one specific anion SO4= among several competitive cations and anions in 1:9 methanol water HEPES buffer medium. This probe with moderate luminescence property exhibits elevated fluorescence enhancement with different shifting of spectral position during detection of Al(III) / Zn(II) and fluorescence diminution at the time of SO4= detection. One another interesting noticeable fact is that, with the help of F− ion Zn(II) can be detected in presence of Al(III) whereas by using CN− ion Al(III) can be detected in presence of Zn(II). The moderately higher binding constant values, measured from the probe-analytes electronic titration and the results obtained from the fluorescence lifetime study, convince us regarding the formation of Zinc/Aluminum/SO4= -probe complexes during sensing by the chemosensor H3L. The 1:1 binding mechanisms between H3L and Al(III)/Zn(II)/SO4= ions are propped up by HR-MS analysis and NMR/FTIR titration. The mononuclear structure of Zn(II)-H3L / Al(III)-H3L and SO4=H3L complexes are optimized by implementing Density Functional Theory (DFT) study. The sensing phenomena of two metal ions are further utilized to form a molecular logic gate formulation. Interestingly, this chemosensor can effectively detect and quantify all the aforementioned ions in tap water. Finally, the bio sensing ability of the chemosensor has been inspected by performing the fluorescence live cell imaging study, showing the intercellular Zn(II) sensing efficacy.

Air resonance enhanced multiphoton ionization tagging velocimetry.

Air resonance enhanced multiphoton ionization (REMPI) tagging velocimetry (ART) was demonstrated in quiescent and supersonic flows. The ART velocimetry method utilizes a wavelength tunable laser beam to resonantly ionize molecular oxygen in air and generate additional avalanche-type ionization of molecular nitrogen. The fluorescence emissions from the first negative and first positive bands of molecular nitrogen are, thus, produced and used for flow tagging. Detailed characterization of ART was conducted, including the effects of oxygen resonance to fluoresce nitrogen, nitrogen fluorescence spectrum, laser energy deposition into quiescent flow showing minimal perturbations in flow, fluorescence lifetime study at various pressures, and line tagging without breakdown. Pointwise velocity measurements within a supersonic flow from a nominal Mach 1.5 nozzle have been conducted and characterized.

Optical and photophysical properties of platinum benzoporphyrins with C2v and D2h symmetry

Platinum(II) mono- and di-benzoporphyrins carrying either ester or imide peripheral groups have been successfully synthesized. These benzoporphyrins possessing C[Formula: see text] and D[Formula: see text] symmetry were investigated using a range of techniques including UV-Vis and phosphorescence spectroscopy, differential pulse voltammetry, and transient absorption spectroscopy covering wide spatial and temporal ranges. Up to three oxidation and three reductions within the accessible potential window of dichlorobenzene were observed. Facile reductions for both mono- and dibenzoporphyrin derivatives, more so with imide peripheral substituents were witnessed. Computational studies were supportive of push-pull type interactions within these molecular systems. The formation of triplet excited states within 5 ps after laser excitation was confirmed by femtosecond transient absorption studies. Nanosecond transient absorption studies coupled with phosphorescence lifetime studies revealed relatively rapid relaxation of the triplet excited states as compared to a controlled platinum porphyrin suggesting push-pull type interactions on a slower time scale.