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Functional materials with long-lived luminescence are extremely valuable due to their vast assortment of applications in optical devices, especially in bioimaging, sensors, security systems and other applications. A long-lived photoluminescent silver nanocluster-infused silver terephthalate metal organic framework (MOF) exhibiting green emission with a longer luminescent lifetime of 3.91 ms (ATP) was developed by a very facile and environmentally friendly method (room temperature, aqueous medium). The long-range array of silver nanoclusters deciphered from HRTEM and STEM images, both as embedded and as percolating out of the silver terephthalate MOF structure together with terephthalic acid ligand, primarily contributes to the longer lifetime of ATP. More interestingly, ATP is very photostable (for several months), which brings forward the scope of several customizable luminescent nanocomposite materials: films, hydrogels, thin film coatings, etc. Model systems were formulated to validate the luminescent property and customizability using base matrices poly(methyl methacrylate) (PMMA), polyvinyl alcohol and polycaprolactone. The intrinsic antibacterial and biofilm inhibition property of ATP befits it for antibacterial applications. [ABSTRACT FROM AUTHOR]

Research has been conducted on the C-alkylated zinc chlorins. The two-step conversion of these compounds to zinc oxochlorins with the keto group located in the macrocycle's reduced ring has been carried out and the details are described.

Research describes the synthesis of a linear array of perylene, porphyrin dimers, and phthalocyanine chromophores and their absorption and fluorescence spectral behavior. Data reveal strong absorption in the range of visible spectrum and energy funneling in a cascade form from perylene to phthalocyanine.

Spectroscopic and EPR studies of dimeric and pentameric porphyrin-based arrays reveal a novel way of communication of electrons in these arrays. The diarylethyne link between two porphoryins leads to energy transfer through weak interactions. Oxidized pentamers have holes, the quick movement of which enables the use of pentamers as parts of electron-transport chains or as molecular wires, when their structure is linear. The pentamers can serve as controlled potential electron reservoirs due to their ability to lose five electrons.

The photochemistry of 2-acylpyridines, 2-acylpyrazines and 3-acylpyridazines and the electronegative substitution effects of E(sub T) in pyrimidines were investigated. The possible mediation of a triplet in hydrogen abstraction by nitrogen was examined for 6-isopentyl-4-pyrimidinecarbonitrile. Hydrogen abstraction and fragmentation reactions were achieved upon irradiation of the compound. Nitrogen and oxygen abstraction were also studied upon irradiation of 2-acylpyridines and 2-acylpyrazines. A correlation was established from the formation of the triplet states of the heteroaromatic ketones.

The photo physical properties of a perylene-porphyrin dyad are examined with the aim of using this construct for molecular photonics applications. The study investigates the use of perylene-imide dyes as accessory pigments with porphyrins, using a longer linker than in Wasielewski's phenyl-linked system in an attempt to suppress electron-transferquenching while maintaining energy transfer.

The photophysical properties of two perylene-porphyrin dyads are examined in detail with the aim of expanding the functional utility of these constructs for molecular optoelectronics applications. The study indicate that perylene-bis(imide) dye diphenylethyne free base porphyrin (PDI-pep-Fb) has the greatest potential utility in photonics applications wherein light harvesting by an accessory pigment, energy transport to an output chromophore, and emission are desired.

Tetraarylporphyrins are used as modular building blocks in a convergent procedure to develop rigid, soluble arrays of covalently-linked porphyrins in different metalation states. The porphyrins are facially-encumbered to inhibit aggregation and have peripheral iodo or ethynyl groups. Light-harvesting compounds can be modelled very well with this procedure. The tetraarylporphyrin building blocks are used to build the diphenylethyne spacer which offers rigid center-to-center distances, and seems to be of suitable length for good light-harvesting.

Starting from readily accessible nitrones and electron-deficient acetylenes, a highly efficient and versatile synthetic protocol for 3- substituted indoles has been developed. [ABSTRACT FROM AUTHOR]

Persistence of the antivibrio property of the potential antagonistic probiotics, Pseudomonas MCCB 102 and 103, at different temperatures, pH and in organic solvents was studied. The antivibrio compound was extracted, purified and characterized using thin-layer chromatography, high-pressure liquid chromatography, liquid chromatography-mass spectroscopy, UV-Vis and nuclear magnetic resonance spectroscopy and identified as N-methyl-1-hydroxyphenazine, a phenazine antibiotic. The toxicity of the compound was tested in Penaeus monodon haemocyte culture and the IC50 value was found to be 1.4 ± 0.31 mg L−1. The compound was found to be bacteriostatic at 0.5 mg L−1. Its stability to varying temperature, pH, organic solvents, prolonged shelf-life and vibriostatic nature point to its suitability for prophylatic aquaculture application. [ABSTRACT FROM AUTHOR]