Spectroscopic and dielectric studies of meso-tetrakis(p-sulfonatophenyl) porphyrin doped hybrid borate glasses

Venkatramaiah, N.; Veeraiah, N.; Venkatesan, R.

doi:10.1016/j.jallcom.2010.11.107

Cited by 12 publications

(9 citation statements)

References 36 publications

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“…Fluorescence decay signals were well fitted to a single exponential with an iterative nonlinear deconvolution fitting method. The fluorescence decay rate did not show the detection wavelength dependence for all samples, implying that the emission state was homogeneity [28]. The fluorescence lifetime and the quantum yield of PaD-OHs were faster and smaller than those of PaD-alkyls as shown in Table 1.…”

Section: Resultsmentioning

confidence: 88%

Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell LineIn Vitro

Wang

Kim

et al. 2014

International Journal of Photoenergy

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Pheophorbide-a derivatives have been reported to be potential photosensitizers for photodynamic therapy (PDT). In this study, photophysics of pheophorbide-a derivatives (PaDs) were investigated along with their photodynamic tumoricidal effectin vitro. PaDs were modified by changing the coil length and/or making the hydroxyl group (–OH) substitutions. Their photophysical properties were studied by steady-state and time-resolved spectroscopic methods. The photodynamic tumoricidal effect was evaluated in the mouse breast cancer cell line (EMT6). Lifetime and quantum yield of fluorescence and quantum yields of triplet state and singlet oxygen were studied to determine the dynamic energy flow. The coil length of the substituted alkyl group did not significantly affect the spectroscopic properties. However, the substitution with the hydroxyl group increased the quantum yields of the triplet state and the singlet oxygen due to the enhanced intersystem crossing. In order to check the application possibility as a photodynamic therapy agent, the PaDs with hydroxyl group were studied for the cellular affinity and the photodynamic tumoricidal effect of EMT6. The results showed that the cellular affinity and the photodynamic tumoricidal effect of PaDs with the hydroxyl group depended on the coil-length of the substituted alkyl group.

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Section: Resultsmentioning

confidence: 88%

Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell LineIn Vitro

Wang

Kim

et al. 2014

International Journal of Photoenergy

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“…Sn(IV)Porphyrins doped hybrid borate glasses were prepared by rapid melt quench technique [15]. In brief, weighed quantities of boric acid (12 g) and 2 mg of various Sn(IV)Porphyrins ( Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The optical band gap (Fig. 4) and urbach's energy was calculated as described earlier [15] and the pertinent data is summarized in Table 1. The E g values were found to vary with the nature of substituents on the phenyl ring of Sn(IV)Porphryin and are closely related to the energy band gap between valance band and conduction band.…”

Section: Optical Absorptionmentioning

confidence: 99%

Enhanced stokes shift of S2→S0 emission and structural investigations of Sn(IV)Porphyrins doped hybrid borate glasses

Venkatramaiah

Ramakrishna

Kumar

et al. 2012

Journal of Alloys and Compounds

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“…Venkatramaiaha et al, has incorporated tpp4 within glassy matrix and dielectric property has been investigated. 12 There is hardly any data regarding the study of relaxation time and dielectric property of chlorophyll a incorporated silica gel in literature. The investigation of dielectric behavior of naturally occurring porphyrene-silica nanocomposite can be useful for various electronic applications.…”

Section: Introductionmentioning

confidence: 99%

High Dielectric Constant Composite Based on Chlorophyll a Entrapped Nanoporous Silica Gel

et al. 2012

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Chlorophyll a (naturally occurring Mg porphyrene) has been entrapped in nano/porous silica gel using sol–gel method at room temperature, producing a stable composite. HRTEM observation reveals regular nanoscale [around 15–20 nm diameter] distribution of aggregated polycrystalline chlorophyll a within porous silica matrix. UV-vis study also corroborates the presence of various aggregated chlorophyll a species within the system. Low field measurement shows almost 400 times enhancement of dielectric constant (1700) with incorporation of only 0.125 mg/ml of chlorophyll and the loss is 0.5 at room temperature at 100 Hz. The dielectric constant of the composite reaches 2500 as chlorophyll concentration becomes 1 mg/ml. Observed strong space charge response to the external field and strong frequency dispersion of the dielectric properties of the composite can be attributed to the long-range electron delocalization [nomadic polarization] in chlorophyll a aggregates. The electric modulus (M*) formalism used in this study enabled us to distinguish and separate various relaxation processes. It is found that with increasing chlorophyll concentration D.C. relaxation time decreases exponentially at room temperature. It is shown that observed relaxations do not perfectly follow the Debye response in high frequency region due to heterogeneous distribution of chlorophyll aggregates. The low values of room temperature activation energy calculated from Arrhenius plot reveal that polaronic hopping phenomena is absent at grain-interfacial region due to low thermal energy.

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Spectroscopic and dielectric studies of meso-tetrakis(p-sulfonatophenyl) porphyrin doped hybrid borate glasses

Cited by 12 publications

References 36 publications

Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell LineIn Vitro

Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell LineIn Vitro

Enhanced stokes shift of S2→S0 emission and structural investigations of Sn(IV)Porphyrins doped hybrid borate glasses

High Dielectric Constant Composite Based on Chlorophyll a Entrapped Nanoporous Silica Gel

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