Covalently linked pyrene antennas for optically dense yet aggregation-resistant light-harvesting systems.

In this study we present a novel energy transfer material inspired by natural light-harvesting antenna arrays, zinc(II) phthalocyanine-pyrene (ZnPcPy). The ZnPcPy system facilitates energy transfer from 16 covalently linked pyrene (Py) donor chromophores to the emissive central zinc(II) phthalocyanine (ZnPc) core. Nearly 98% energy transfer efficiency is determined from the changes in emission decay rates between free MePy to covalently linked Py, supported by comparisons of photoluminescence quantum yields using different excitation wavelengths. A comparative analysis of ZnPcPy and an equivalent mixture of ZnPc and MePy demonstrates the superior light-harvesting performance of the covalently linked system, with energy transfer rates 9705 times higher in the covalently bound system. This covalent strategy allows for very high loadings of absorbing Py chromophores to be achieved while also avoiding exciton quenching that would otherwise arise, with the same strategy widely applicable to other pairs of Forster resonance energy transfer (FRET) chromophores.

Development of Uniform Porous Carbons From Polycarbazole Phthalonitriles as Durable CO2 Adsorbent and Supercapacitor Electrodes.

Advances in new porous materials have recognized great consideration in CO2 capture and electrochemical energy storage (EES) applications. In this study, we reported a synthesis of two nitrogen-enriched KOH-activated porous carbons prepared from polycarbazole phthalonitrile networks through direct pyrolysis protocol. The highest specific surface area of the carbon material prepared by pyrolysis of p-4CzPN polymer reaches 1,279 m2 g-1. Due to the highly rigid and reticular structure of the precursor, the obtained c-4CzPN-KOH carbon material exhibits high surface area, uniform porosity, and shows excellent CO2 capture performance of 19.5 wt% at 0°C. Moreover, the attained porous carbon c-4CzPN-KOH showed high energy storage capacities of up to 451 F g-1 in aqueous electrolytes containing 6.0 M KOH at a current density of 1 A g-1. The prepared carbon material also exhibits excellent charge/discharge cycle stability and retains 95.9% capacity after 2000 cycles, indicating promising electrode materials for supercapacitors.

A highly sensitive "ON-OFF-ON" dual optical sensor for the detection of Cu(II) ion and triazole pesticides based on novel BODIPY-substituted cavitand.

The synthesis with full structural characterization including elemental analysis and 1H, 13C, 11B and 19F NMR, FT-IR and MALDI-TOF spectral data, along with the florescence sensing behavior of a new resorcin[4]arene cavitand 3 bearing multiple BODIPY sites achieved by the Cu-catalyzed azide-alkyne cycloaddition (CuAAC) is being reported. The spatial orientation of multiple BODIPY-1,2,3-triazole arms based on the macrocyclic rigid core is of great interest since the resulting structure has been utilized as a fluorescent chemosensor for numerous metal cations. In particular, a remarkable decrease in the fluorescence emission towards Cu(ii) ions, i.e., "turn-off" response, has been obtained giving rise to an optical sensor for the detection of triazole fungicides, namely tebuconazole, triadimenol, triadimefon, i.e. "turn-on" response. Such a molecular system, hence, can be feasibly applied as a dual optical sensor, i.e. "a turn-on-off-on" system, for dangerous contaminants such as heavy metals and pesticides.

A synergetic and sensitive physostigmine pesticide sensor using copper complex of 3D zinc (II) phthalocyanine-SWCNT hybrid material.

2,3,9,10,16,17,23,24-Octakis (4-methyl-2,6-bis((prop-2-yn-1-yloxy)methyl)phenoxy) phthalocyaninato zinc(II) (Pc) bearing sixteen terminal ethynyl groups was synthesized and attached to SWCNT (Single-walled carbon nanotube) covalently to obtain three dimensional porous hybrid material (SWCNT-Pc 3D) and its copper complex (Cu-SWCNT-Pc 3D). The structural characterization and electrochemical sensor features of the Cu-SWCNT-Pc hybrid towards to physostigmine pesticide were performed. A fast, direct and suitable determination method for physostigmine detection was offered. The designed sensor, Cu-SWCNT-Pc 3D/GCE (glassy carbon electrode) shows sensitivity ca 1.8, 4.3 and 2.8 times more than that of SWCNT/GCE, SWCNT-Pc-noncovalent/GCE and SWCNT-Pc 3D/GCE in terms of peak heights while bare and Pc/GCE had almost no voltammetric response to 2 µM physostigmine in PBS at a pH of 7.0. The limit of detection and quantification of physostigmine determination with Cu-SWCNT-Pc 3D/GCE were found to be 53 and 177 nM in the range of 0.1-4.8 µM, respectively. This study demonstrated that the modification of the GCE with Cu-SWCNT-Pc 3D as an electrochemical sensor was acted as catalytic role toward physostigmine presence of other interfering pesticides as high sensitivity and selectivity. The electrochemical determination of physostigmine in real samples was performed under the optimized conditions, also accuracy of the electrochemical determination method was evaluated with HPLC as a standard determination method.

Dually directional glycosylated phthalocyanines as extracellular red-emitting fluorescent probes.

The development of new non-aggregated phthalocyanines bearing multivalent saccharide moieties on their macrocyclic rims is of great interest. Many characteristics, including water-solubility, non-toxicity and others, can be feasibly obtained by these amphiphiles which can be considered as a key solution for demonstrating highly efficient photoactive materials in water. Herein, a family of five newly prepared dually directional Zn(ii) containing phthalocyanines (PcG1-4) and azaphthalocyanine (AzaPcG1) glycoconjugates is described. The unique spatial arrangement of the glucoside units based on peripherally hexadeca-(PcG1) and nonperipherally octa-(PcG4) macrocycles provides a fully monomeric behaviour along with a high fluorescence (ΦF∼ 0.21) in aqueous solution. These amphiphiles were characterized by low toxicity, and an extremely low cellular uptake was obtained due to the highly polar nature of the glucoside substituents. Accordingly, their potential as suitable photoactive chromophores for red-emitting extracellular fluorescent probes has been confirmed upon the evaluation of paracellular transport using a layer of MDCKII cells with the permeability coefficient fully comparable with an established evaluator of the integrity of the monolayer.

Multivalent Allyl-Substituted Macrocycles as Nonaggregating Building Blocks.

Based on the concept of dual-directionality, the synthesis of two novel zinc(II)-containing phthalocyanine (Pc-ene1) and azaphthalocyanine (AzaPc-ene1) macrocycles bearing dual directional (up/down) allyl moieties on their rims is reported. Their structural identification, that is, NMR, FT-IR, UV-vis, MALDI-TOF spectral data, single crystal X-ray diffraction, and CHN elemental analyses, along with their nonaggregating behaviors in solvated media and crystalline forms has been confirmed.

Push-Pull Zinc Phthalocyanine Bearing Hexa-Tertiary Substituted Carbazolyl Donor Groups for Dye-Sensitized Solar Cells.

An asymmetrical, push-pull phthalocyanine bearing bulky tert-butylcarbazolyl moieties as electron donor and carboxylic acid as anchoring group was synthetized and tested as a photosensitizer in dye-sensitized solar cells (DSSC). The new photosensitizer was characterized by 1H and 13C NMR, UV-Vis and mass spectrometry. The bulky tert-butylcarbazolyl moieties avoid the aggregation of the phthalocyanine dye. DFT studies indicate that the HOMO is delocalized throughout the -electron system of the substituted phthalocyanine and the LUMO is located on the core of the molecule with a sizable electron density distribution on carboxyl groups. The new dye has been used as a photosensitizer in transparent and opaque dye-sensitized solar cells, which exhibit poor efficiencies related to a low Jsc.

Photo-physicochemical properties of water-soluble non-aggregated indium(III) phthalocyanines.

Phthalocyanines have interesting optoelectronic properties but typically suffer from aggregation in aqueous solution, which can limit their applicability, especially in photodynamic therapy. In this study, indium(III) phthalocyanine peripherally substituted with eight triazolyl-containing phenoxy groups (InOAc) and its water-soluble analogue (Q-InOAc) were synthesised and structurally characterised. Heavy metal effects, exerted by the central indium ion, on the photosensitising and photophysical properties (singlet oxygen quantum yield, singlet state lifetime and quantum yield, and triplet state lifetime) were investigated in both DMF and D2O. Highly efficient generation of the triplet excited state (T1), induced by the incorporation of a large atom, enhanced singlet oxygen formation, as revealed by both chemical and physical methods. Correspondingly, the singlet oxygen quantum yield (ΦΔ) of Q-InOAc was 0.603 in DMF and 0.433 in D2O. These values are higher than those previously reported for the corresponding metal-free, Mg-based, and Zn-based water-soluble phthalocyanines (HH, Mg, and Zn). Consequently, Q-InOAc is expected to be an excellent photosensitiser for photodynamic therapy.

Carbazole-tagged pyridinic microporous network polymer for CO2 storage and organic dye removal from aqueous solution.

A microporous organic polymer (Cz-pyr-P) was prepared from a monomer of pyridine-imides, flanked by four carbazoles, and its application as an adsorbent for both CO2 and methylene blue dye in wastewater was investigated. The polymer was synthesised by oxidative polymerisation facilitated by FeCl3 and comprehensively characterised using routine spectroscopic, thermal, textural, and morphological analyses. With a high surface area of 1065 m2/g and a median pore width of 8.06 Å, the nitrogen-enriched Cz-pyr-P reversibly adsorbed 19.41 wt% (273 K) and 12.78 wt% (295 K) CO2 at 1 bar, with a good isosteric heat value of CO2 adsorption (28.5 kJ/mol). For the removal of methylene blue dye from wastewater, Cz-pyr-P exhibited excellent partition coefficient of 380.10 mg/g µM with an equilibrium time of 6 min which is shorter than previously reported values for other materials. The results indicate that Cz-pyr-P with desirable functionality could be utilised for reaching CO2 emission reduction targets as well as for wastewater treatment.

Evaluation of the Intramolecular Charge-Transfer Properties in Solvatochromic and Electrochromic Zinc Octa(carbazolyl)phthalocyanines.

2,3,9,10,16,17,23·24-Octakis-(9H-carbazol-9-yl) phthalocyaninato zinc(II) (3) and 2,3,9,10,16,17,23·24-octakis-(3,6-di-tert-butyl-9H-carbazole) phthalocyaninato zinc(II) (4) complexes were prepared and characterized by NMR and UV-vis spectroscopies, magnetic circular dichroism (MCD), matrix-assisted laser desorption ionization mass spectrometry, and X-ray crystallography. UV-vis and MCD data are indicative of the interligand charge-transfer nature of the broad band observed in 450-500 nm range for 3 and 4. The redox properties of 3 and 4 were probed by electrochemical and spectro-electrochemical methods, which are suggestive of phthalocyanine-centered first oxidation and reduction processes. Photophysics of 3 and 4 were investigated by steady-state fluorescence and time-resolved transient absorption spectroscopy demonstrating the influence of the carbazole substituents on deactivation from the first excited state in 3 and 4. Protonation of the meso-nitrogen atoms in 3 results in much faster deactivation kinetics from the first excited state. Spectroscopic data were correlated with density functional theory (DFT) and time-dependent DFT calculations on 3 and 4.

Phthalocyanines and Tetrapyrazinoporphyrazines with Two Cationic Donuts: High Photodynamic Activity as a Result of Rigid Spatial Arrangement of Peripheral Substituents.

High photodynamic activity was observed for hexadeca-cationic zinc, magnesium, and metal-free phthalocyanines (Pcs) and tetrapyrazinoporphyrazines with EC50 values as low as 5 nM (MCF-7 cells) for the best compound; this activity was several times better than that of clinically established photosensitizers verteporfin, temoporfin, S3AlOHPc, or protoporphyrin IX. This lead compound was characterized by low dark toxicity (TC50 = 369 µM), high efficiency against other cell lines (HCT 116 and HeLa), and possible activation by light above 680 nm. The excellent photodynamic activity resulted from the rigid spatial arrangement of the quaternized triazole moieties above and below the Pc core, as confirmed by X-ray crystallography. The triazole moieties thus formed two "cationic donuts" that protected the hydrophobic core against aggregation in water. The lysosomes were found to be the site of subcellular localization and were consequently the primary targets of photodynamic injury, resulting in predominantly necrotic cell death.

Water-soluble non-aggregating zinc phthalocyanine and in vitro studies for photodynamic therapy.

Newly synthesized zinc phthalocyanine bearing sixteen quaternized imidazolyl moieties on the periphery displays high water-solubility, lack of aggregation and high singlet oxygen quantum yield in water (ΦΔ > 0.33). The in vitro tests indicated excellent anticancer photodynamic activity (EC50 = 36.7 nM) and low dark toxicity to non-cancerous cells (TC50 = 395 µM).

2-Aminothiophenes as building blocks in heterocyclic synthesis: synthesis and antimicrobial evaluation of a new class of pyrido[1,2-a]thieno[3,2-e]pyrimidine, quinoline and pyridin-2-one derivatives.

Multisubstituted 2-aminothiophenes 1a-c can be readily cyanoacylated via reaction with cyanoacetic acid in presence of acetic anhydride under a microwave irradiation to form the corresponding cyanoacetamides 2a-c, which condensed with DMF-DMA to form the corresponding enamines 4 that reacted with hydrazine hydrate to yield the aminopyrazoles 5. Moreover the cyanoacetamides 2a-c reacted with a variety of arylidenmalononitrile to afford a novel pyrido[1,2-a]thieno[3,2-e]pyrimidine derivatives 12a-o. In addition the enamines 4a,b reacted with malononitrile to afford the pyrido[1,2-a]thieno[3,2-e]pyrimidine derivatives 19a,b. The cyanoacetamides 2a,b reacted also with salicylaldehyde to afford the quinoline derivatives 24a,b. Moreover the cyanoacetamides 2a,b reacted with the enaminones 25a-c to form the corresponding Pyridin-2-one derivatives 29a-c. Reactions of 2a,c with bezenediazonium chloride afford the arylhydrazones 30a,b that reacted with chloroacetonitrile to form the acyclic product 31 which could not be further cyclized to the corresponding 4-aminopyrazole. The X-ray crystallographic analyses of seven products could be obtained thus establishing with certainty the proposed structures in this work. Most of the synthesized compounds in this investigation were tested and evaluated as antimicrobial agents.

Acylation of heteroaromatic amines: facile and efficient synthesis of a new class of 1,2,3-triazolo[4,5-b]pyridine and pyrazolo[4,3-b]pyridine derivatives.

1,2,3-Triazolo[4,5-b]pyridines and pyrazolo[4,3-b]pyridines can be readily prepared via cyanoacetylation reactions of 5-amino-1,2,3-triazoles 1a,b and 4-amino- pyrazole 2 followed by subsequent cyclization of the formed cyanoacetamides. Reactions of amines 1a,b with a mixture of p-nitrophenylacetic acid and acetic anhydride under microwave irradiation conditions afforded the corresponding amides 15a,b that underwent cyclization to form 1,2,3-triazolo[4,5-b]pyridines 16a,b upon heating in DMF solutions containing sodium acetate. Reactions of 1a,b with active methylene compounds, including 17a-c, in the presence of zeolites as catalyst also afforded 1,2,3-triazolo[4,5-b]pyridine derivatives 20a-f via the intermediacy of triazole derivatives 19 and not 18.

Applications of 2-arylhydrazononitriles in synthesis: preparation of new indole containing 1,2,3-triazole, pyrazole and pyrazolo[1,5-a]pyrimidine derivatives and evaluation of their antimicrobial activities.

In this effort, 2-arylhdrazononitriles were used as key synthons for the preparation of wide variety of new, uniquely substituted heterocyclic substances. In addition, the results of biological evaluations demonstrate that members of the group prepared have promising antimicrobial activities against Gram negative bacteria, Gram positive bacteria and Yeast. In the synthetic sequences, 3-(1-methyl-1H-indol-3-yl)-3-oxo-2-(phenylhydrazono)propanenitrile 2a and its 2-methyl derivative 2b were found to react with hydroxylamine hydrochloride to yield the corresponding indolyl-5-amino-2-phenyl-1,2,3-triazoles 4a,b. These amines react with cyanoacetic acid in presence of acetic anhydride either thermally or under microwave irradiation conditions to yield the corresponding cyanoacetamides 5a,b, which condensed readily with dimethylformamide dimethylacetal to yield the enaminonitriles 6a,b. Whereas heating of 6a,b with hydrazine hydrate affords compound 8, compound 12 is produced when these reactants are subjected to microwave irradiation. We observed that the aminopyrazole 9 reacts with enaminal 13 to yield 14 and that its reactions with enaminones 15 afford 17. Finally, compound 5 reacts with cinnamaldehyde to yield the corresponding Schiff's base 18 that does not undergo cyclization to form the pyridine derivative 19. The activities of all new substances synthesized in this investigation were evaluated against a panel of microbial organisms. The results show that 4a, 4b, 5b and 9b display strong antimicrobial activities against all of the tested organisms.

Hydrogen adsorption in microporous organic framework polymer.

A microporous organic framework polymer (OFP) based on a polyimide framework exhibits a high surface area (1159 m2 g(-1)) and shows a reversible H2 storage capacity of 3.94 wt% at 10 bar and 77 K, the highest yet reported for an organic polymer.

Clathrate formation from octaazaphthalocyanines possessing bulky phenoxyl substituents: a new cubic crystal containing solvent-filled, nanoscale voids.

The synthesis of octaazaphthalocyanine (AzaPc) derivatives, with bulky phenoxyl substituents placed at eight peripheral positions and containing either H(+), Ni(2+) or Zn(2+) ions in their central cavity, is described. The required precursors, derivatives of pyrazine-2,3-dicarbonitrile, were prepared using a nucleophilic aromatic substitution reaction between 2,6-diisopropylphenol or 2,6-diphenylphenol and 5,6-dichloropyrazine-2,3-dicarbonitrile. Analysis of the resulting AzaPcs by UV/Visible and (1)H NMR spectroscopy confirms that steric isolation of the AzaPc cores was enforced both in solution and in the solid state. X-ray diffraction studies of single crystals of the AzaPcs reveal that solvent inclusion takes place in each case. Of particular significance is the finding that the zinc derivative of 2,3,9,10,16,17,23,24-octa-(2,6-diisopropylphenoxy)octaazaphthalocyanine provides nanoporous cubic crystals, containing massive (8 nm(3)) solvent-filled voids, similar to those of the analogous phthalocyanine derivative. Exchange of the included solvent within the voids can be readily achieved by using a number of alternative solvents including water. Based on the observed loading of included water, the internal volume of this nanoporous cubic crystal appears to be more hydrophilic than its phthalocyanine counterpart.

Polymers of intrinsic microporosity (PIMs): bridging the void between microporous and polymeric materials.

Novel types of microporous material are required for chemoselective adsorptions, separations and heterogeneous catalysis. This concept article describes recent research directed towards the synthesis of polymeric materials that possess microporosity that is intrinsic to their molecular structures. These polymers (PIMs) can exhibit analogous behaviour to that of conventional microporous materials, but, in addition, may be processed into convenient forms for use as membranes. The excellent performance of these membranes for gas separation and pervaporation illustrates the unique character of PIMs and suggests immediate technological applications.

Polymers of intrinsic microporosity (PIMs): robust, solution-processable, organic nanoporous materials.

Microporous materials can be derived directly from soluble polymers whose randomly contorted shapes prevent an efficient packing of the macromolecules in the solid state.