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Kenneth W. Jolley - One of the best experts on this subject based on the ideXlab platform.

  • porphyrins as light harvesters in the dye sensitised tio2 solar cell
    Coordination Chemistry Reviews, 2004
    Co-Authors: Wayne M. Campbell, Anthony K Burrell, David L. Officer, Kenneth W. Jolley
    Abstract:

    Abstract The sensitisation of TiO 2 with a wide variety of inorganic and organic dyes for light harvesting has been investigated over the last 20 years for the development of efficient solar cells. Given their efficacy in photosynthesis, porphyrin dyes have great potential in this regard. A significant number of porphyrins have been evaluated in photoelectrochemical cells (PECs), but little is known about the structural and electronic features required for efficient porphyrin light harvesting on semiconductors (SCs). One of the most appealing aspects of the use of porphyrins as dyes is that a wide variety of large porphyrin arrays can now be synthesised. The attachment of such arrays (or light harvesting antennae) to SCs such as TiO 2 provides the potential to dramatically increase the dye surface coverage of the SC, and therefore the dye-sensitised solar cell (DSSC) efficiency. There has been little work carried out in this area to date. Following the development of an efficient building block approach to functionalised porphyrin arrays, we have synthesised a variety of β-Carboxylic substituted porphyrin monomers and multi-porphyrin arrays and evaluated their performance in the dye-sensitised TiO 2 (Gratzel) solar cell. The effect of porphyrin substituent, functional group position, linker conjugation, binding group and electrolyte on the porphyrin light harvesting efficiency was investigated. It was found that a β-substituted monoporphyrin Carboxylic Acid Derivative with a conjugated linker shows significant advantage over any antennae-type of multi-porphyrin arrays. In particular, of all the porphyrins evaluated, 4- trans -2′-(2″-(5″,10″,15″,20″-tetraphenylporphyrinato zinc(II)yl)ethen-1′-yl)-1-benzoic Acid gives an overall efficiency of 4.2% under AM1.5 conditions in an unoptimised Gratzel cell, making it one of the most efficient porphyrin dye sensitisers synthesised to date.

  • Porphyrins as light harvesters in the dye-sensitised TiO2solar cell
    Coordination Chemistry Reviews, 2004
    Co-Authors: Wayne M. Campbell, Anthony K Burrell, David L. Officer, Kenneth W. Jolley
    Abstract:

    The sensitisation of TiO2with a wide variety of inorganic and organic dyes for light harvesting has been investigated over the last 20 years for the development of efficient solar cells. Given their efficacy in photosynthesis, porphyrin dyes have great potential in this regard. A significant number of porphyrins have been evaluated in photoelectrochemical cells (PECs), but little is known about the structural and electronic features required for efficient porphyrin light harvesting on semiconductors (SCs). One of the most appealing aspects of the use of porphyrins as dyes is that a wide variety of large porphyrin arrays can now be synthesised. The attachment of such arrays (or light harvesting antennae) to SCs such as TiO2provides the potential to dramatically increase the dye surface coverage of the SC, and therefore the dye-sensitised solar cell (DSSC) efficiency. There has been little work carried out in this area to date. Following the development of an efficient building block approach to functionalised porphyrin arrays, we have synthesised a variety of β-Carboxylic substituted porphyrin monomers and multi-porphyrin arrays and evaluated their performance in the dye-sensitised TiO2(Grätzel) solar cell. The effect of porphyrin substituent, functional group position, linker conjugation, binding group and electrolyte on the porphyrin light harvesting efficiency was investigated. It was found that a β-substituted monoporphyrin Carboxylic Acid Derivative with a conjugated linker shows significant advantage over any antennae-type of multi-porphyrin arrays. In particular, of all the porphyrins evaluated, 4-trans-2′- (2″-(5″,10″,15″,20″-tetraphenylporphyrinato zinc(II)yl)ethen-1′-yl)-1-benzoic Acid gives an overall efficiency of 4.2% under AM1.5 conditions in an unoptimised Grätzel cell, making it one of the most efficient porphyrin dye sensitisers synthesised to date. © 2004 Elsevier B.V. All rights reserved.

Simon M Ametamey - One of the best experts on this subject based on the ideXlab platform.

  • synthesis and preliminary evaluation of a 2 oxoquinoline Carboxylic Acid Derivative for pet imaging the cannabinoid type 2 receptor
    Pharmaceuticals, 2014
    Co-Authors: Linjing Mu, Roger Slavik, Adrienne Muller, Kasim Popaj, Stjepko Cermak, Markus Weber, Roger Schibli, Stefaniedorothea Kramer, Simon M Ametamey
    Abstract:

    Cannabinoid receptor subtype 2 (CB2) has been shown to be up-regulated in activated microglia and therefore plays an important role in neuroinflammatory and neurodegenerative diseases such as multiple sclerosis, amyotrophic lateral sclerosis and Alzheimer’s disease. The CB2 receptor is therefore considered as a very promising target for therapeutic approaches as well as for imaging. A promising 2-oxoquinoline Derivative designated KP23 was synthesized and radiolabeled and its potential as a ligand for PET imaging the CB2 receptor was evaluated. [11C]KP23 was obtained in 10%–25% radiochemical yield (decay corrected) and 99% radiochemical purity. It showed high stability in phosphate buffer, rat and mouse plasma. In vitro autoradiography of rat and mouse spleen slices, as spleen expresses a high physiological expression of CB2 receptors, demonstrated that [11C]KP23 exhibits specific binding towards CB2. High spleen uptake of [11C]KP23 was observed in dynamic in vivo PET studies with Wistar rats. In conclusion, [11C]KP23 showed promising in vitro and in vivo characteristics. Further evaluation with diseased animal model which has higher CB2 expression levels in the brain is warranted.

M A Neelakantan - One of the best experts on this subject based on the ideXlab platform.

  • fluorescence response of a thiazolidine Carboxylic Acid Derivative for the selective and nanomolar detection of zn ii ions quantum chemical calculations and application in real samples
    RSC Advances, 2015
    Co-Authors: Chithiraivel Balakrishnan, S Thalamuthu, M Theetharappan, Satheesh Natarajan, M A Neelakantan
    Abstract:

    A thiazolidine Carboxylic Acid Derivative (L) was conveniently synthesized and characterized by spectral techniques and single crystal X-ray crystallography. The complexation of L with zinc (L–Zn2+) was studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) and further substantiated by 1H NMR and ESI-MS analysis. The L showed excellent specificity and sensitivity towards a zinc-induced fluorescence response by forming a 1 : 1 complex (Job's plot) in a 95% (v/v) water–methanol mixture. The presence of zinc ions causes ∼40 fold fluorescence enhancement at 481 nm (quantum yield, Φ = 0.19) and can be detected with the naked eye under a UV-lamp. The L can detect Zn2+ in nanomolar levels (13.90 nM) with good tolerance in the presence of other interfering metal ions. The reversibility of L–Zn2+ complexation was checked by EDTA titration. The maximum fluorescence enhancement by Zn2+ binding of L was observed in the pH range of 7.0–9.0. The dissociation constants of L and the stability constant of the L–Zn2+complex in 0.15 M NaClO4 were determined by pH metrically. Theoretical calculations were done using density functional theory (DFT) to support the above findings. L was successfully applied for the determination of Zn2+ in water samples. The compound (L) detects the presence of, Klebsiella pneumoniae and E. coli in water samples.

  • dna binding nuclease and colon cancer cell inhibitory activity of a cu ii complex of a thiazolidine 4 Carboxylic Acid Derivative
    Journal of Coordination Chemistry, 2013
    Co-Authors: S Thalamuthu, B Annaraj, Smreti Vasudevan, Suparna Sengupta, M A Neelakantan
    Abstract:

    Thiazolidine-4-Carboxylic Acid Derivative (L) derived by condensation of D-penicillamine and 3-methoxy salicylaldehyde was used in synthesis of a copper complex (CuL). The ligand and Cu(II) complex were characterized by elemental analysis and spectral techniques. The DNA binding properties of L and CuL with calf thymus DNA were investigated by various techniques. The ability of compounds to break pUC19 DNA was checked by gel electrophoresis. The radical-scavenging activity was studied using 2,2-diphenyl-1-picrylhydrazyl assay. The ligand and CuL exert cytotoxicity against HCT116 cell line. The compounds were screened for antimicrobial activity against several microorganisms. The effect of the CuL on the surface of penicillium was analyzed by scanning electron microscopy.

Shujun Chao - One of the best experts on this subject based on the ideXlab platform.

  • fe n c catalysts synthesized by heat treatment of iron triazine Carboxylic Acid Derivative complex for oxygen reduction reaction
    RSC Advances, 2014
    Co-Authors: Shujun Chao, Panhao Wang, Kui Wang, Lin Yang
    Abstract:

    4,4′,4′′-s-Triazine-1,3,5-triyltri-p-aminobenzoic Acid (H3TATAB) was used as a ligand to prepare an iron–TATAB (Fe–TATAB) complex for the development of an effective oxygen reduction reaction (ORR) catalyst. The activity of the catalyst depended on weight ratios between the Fe–TATAB complex and carbon black and heat-treated temperatures. The results showed that the Fe–N70%/C-800 catalyst (the weight ratio of Fe complex to carbon black was 70 : 30 and the catalyst was pyrolyzed at 800 °C) had good catalytic activity toward ORR with the onset potential at 0.91 V vs. RHE and a kinetic current density of 4.3 mA cm−2 at 0.6 V vs. RHE in alkaline medium. Moreover, the Fe–N70%/C-800 catalyst had better tolerance to methanol crossover effect in comparison with commercial Pt/C (20%). The morphology and composition of the catalysts were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) as well as X-ray photoelectron spectroscopic (XPS). The electrocatalytic activities were demonstrated by cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometric measurements and stability accelerated tests. According to rotating disk electrode (RDE) measurements and Koutecky–Levich analysis, the overall electron transfer number in the catalyzed ORR was found to be 3.7–3.9 and the ORR process was mainly a four-electron pathway. The results indicate that the Fe–N70%/C-800 catalyst may be a promising cathode catalyst for ORR.

Wayne M. Campbell - One of the best experts on this subject based on the ideXlab platform.

  • porphyrins as light harvesters in the dye sensitised tio2 solar cell
    Coordination Chemistry Reviews, 2004
    Co-Authors: Wayne M. Campbell, Anthony K Burrell, David L. Officer, Kenneth W. Jolley
    Abstract:

    Abstract The sensitisation of TiO 2 with a wide variety of inorganic and organic dyes for light harvesting has been investigated over the last 20 years for the development of efficient solar cells. Given their efficacy in photosynthesis, porphyrin dyes have great potential in this regard. A significant number of porphyrins have been evaluated in photoelectrochemical cells (PECs), but little is known about the structural and electronic features required for efficient porphyrin light harvesting on semiconductors (SCs). One of the most appealing aspects of the use of porphyrins as dyes is that a wide variety of large porphyrin arrays can now be synthesised. The attachment of such arrays (or light harvesting antennae) to SCs such as TiO 2 provides the potential to dramatically increase the dye surface coverage of the SC, and therefore the dye-sensitised solar cell (DSSC) efficiency. There has been little work carried out in this area to date. Following the development of an efficient building block approach to functionalised porphyrin arrays, we have synthesised a variety of β-Carboxylic substituted porphyrin monomers and multi-porphyrin arrays and evaluated their performance in the dye-sensitised TiO 2 (Gratzel) solar cell. The effect of porphyrin substituent, functional group position, linker conjugation, binding group and electrolyte on the porphyrin light harvesting efficiency was investigated. It was found that a β-substituted monoporphyrin Carboxylic Acid Derivative with a conjugated linker shows significant advantage over any antennae-type of multi-porphyrin arrays. In particular, of all the porphyrins evaluated, 4- trans -2′-(2″-(5″,10″,15″,20″-tetraphenylporphyrinato zinc(II)yl)ethen-1′-yl)-1-benzoic Acid gives an overall efficiency of 4.2% under AM1.5 conditions in an unoptimised Gratzel cell, making it one of the most efficient porphyrin dye sensitisers synthesised to date.

  • Porphyrins as light harvesters in the dye-sensitised TiO2solar cell
    Coordination Chemistry Reviews, 2004
    Co-Authors: Wayne M. Campbell, Anthony K Burrell, David L. Officer, Kenneth W. Jolley
    Abstract:

    The sensitisation of TiO2with a wide variety of inorganic and organic dyes for light harvesting has been investigated over the last 20 years for the development of efficient solar cells. Given their efficacy in photosynthesis, porphyrin dyes have great potential in this regard. A significant number of porphyrins have been evaluated in photoelectrochemical cells (PECs), but little is known about the structural and electronic features required for efficient porphyrin light harvesting on semiconductors (SCs). One of the most appealing aspects of the use of porphyrins as dyes is that a wide variety of large porphyrin arrays can now be synthesised. The attachment of such arrays (or light harvesting antennae) to SCs such as TiO2provides the potential to dramatically increase the dye surface coverage of the SC, and therefore the dye-sensitised solar cell (DSSC) efficiency. There has been little work carried out in this area to date. Following the development of an efficient building block approach to functionalised porphyrin arrays, we have synthesised a variety of β-Carboxylic substituted porphyrin monomers and multi-porphyrin arrays and evaluated their performance in the dye-sensitised TiO2(Grätzel) solar cell. The effect of porphyrin substituent, functional group position, linker conjugation, binding group and electrolyte on the porphyrin light harvesting efficiency was investigated. It was found that a β-substituted monoporphyrin Carboxylic Acid Derivative with a conjugated linker shows significant advantage over any antennae-type of multi-porphyrin arrays. In particular, of all the porphyrins evaluated, 4-trans-2′- (2″-(5″,10″,15″,20″-tetraphenylporphyrinato zinc(II)yl)ethen-1′-yl)-1-benzoic Acid gives an overall efficiency of 4.2% under AM1.5 conditions in an unoptimised Grätzel cell, making it one of the most efficient porphyrin dye sensitisers synthesised to date. © 2004 Elsevier B.V. All rights reserved.