Synthesis, X-ray Structures, and Optical and Magnetic Properties of Cu(II) Octafluoro-octakisperfluoro(isopropyl)phthalocyanine: The Effects of Electron Addition and Fluorine Accretion.

The stepwise reduction of copper(II) 1,4,8,11,15,18,22,25-octafluoro-2,3,9,10,16,17,23,24-octakisperfluoro(isopropyl) phthalocyanine (CuFPc) in -dichlorobenzene (CHCl) by potassium graphite in the presence of cryptand(K), abbreviated L, results in the formation of (L)[Cu(FPc)]·2CHCl (), (L)[Cu(FPc)]·CHCl (), and (L)[Cu(FPc)] () complexes. Single-crystal X-ray structures revealed their composition and a monotonic increase with increased phthalocyanine (Pc) negative charges of the magnitude of alternative shortening and elongation of the prior equivalent N-C bonds. The complexes are separated by bulky CF substituents, large cryptand counterions, and solvent molecules.

Photoelectrochemical Behavior of Phthalocyanine-Sensitized TiO in the Presence of Electron-Shuttling Mediators.

Dye-sensitized TiO has found many applications for dye-sensitized solar cells (DSSC), solar-to-chemical energy conversion, water/air purification systems, and (electro)chemical sensors. We report an electrochemical system for testing dye-sensitized materials that can be utilized in photoelectrochemical (PEC) sensors and energy conversion. Unlike related systems, the reported system does not require a direct electron transfer from semiconductors to electrodes.

Correlation between the Fluorination Degree of Perfluorinated Zinc Phthalocyanines, Their Singlet Oxygen Generation Ability, and Their Photoelectrochemical Response for Phenol Sensing.

Electron-withdrawing perfluoroalkyl peripheral groups grafted on phthalocyanine (Pc) macrocycles improve their single-site isolation, solubility, and resistance to self-oxidation, all beneficial features for catalytic applications. A high degree of fluorination also enhances the reducibility of Pcs and could alter their singlet oxygen (O) photoproduction. The ethanol/toluene 20:80 vol % solvent mixture was found to dissolve perfluorinated FPcZn complexes, = 16, 52, and 64, and minimize the aggregation of the sterically unencumbered FPcZn.

Nanobody-Based Immunosensor Detection Enhanced by Photocatalytic-Electrochemical Redox Cycling.

Detection of antigenic biomarkers present in trace amounts is of crucial importance for medical diagnosis. A parasitic disease, human toxocariasis, lacks an adequate diagnostic method despite its worldwide occurrence. The currently used serology tests may stay positive even years after a possibly unnoticed infection, whereas the direct detection of a re-infection or a still active infection remains a diagnostic challenge due to the low concentration of circulating parasitic antigens.

Enhanced Photoelectrochemical Detection of an Analyte Triggered by Its Concentration by a Singlet Oxygen-Generating Fluoro Photosensitizer.

The use of a photocatalyst (photosensitizer) which produces singlet oxygen instead of enzymes for oxidizing analytes creates opportunities for designing cost-efficient and sensitive photoelectrochemical sensors. We report that perfluoroisopropyl-substituted zinc phthalocyanine (FPcZn) interacts specifically with a complex phenolic compound, the antibiotic rifampicin (RIF), but not with hydroquinone or another complex phenolic compound, the antibiotic doxycycline. The specificity is imparted by the selective preconcentration of RIF in the photocatalytic layer, as revealed by electrochemical and optical measurements, complemented by molecular modeling that confirms the important role of a hydrophobic cavity formed by the -perfluoropropyl groups of the photocatalyst.

The influence of intermolecular coupling on electron and ion transport in differently substituted phthalocyanine thin films as electrochromic materials: a chemistry application of the Goldilocks principle.

The transport of both electrons and ions in organic mixed ionic and electronic conductors such as phthalocyanines, is essential to allow redox reactions of entire films and, hence, to impart electrochromism. Thin films of a new type, tetrakis-perfluoroisopropyl-perfluoro phthalocyanine, F40PcCu of different thicknesses were obtained via vapor deposition. The extent of the intermolecular coupling within the F40PcCu films established by van der Waals interactions was investigated by in situ optical spectroscopy during film growth.

Optimized Photoelectrochemical Detection of Essential Drugs Bearing Phenolic Groups.

The World Health Organization (WHO) model "List of Essential Medicines" includes among indispensable medicines antibacterials and pain and migraine relievers. Monitoring their concentration in the environment, while challenging, is important in the context of antibiotic resistance as well as their production of highly toxic compounds via hydrolysis. Traditional detection methods such as high-performance liquid chromatography (HPLC) or LC combined with tandem mass spectrometry or UV-vis spectroscopy are time-consuming, have a high cost, require skilled operators and are difficult to adapt for field operations.

Synthesis and Photophysical and Photocatalytic Properties of a Highly Fluorinated and Durable Phthalocyanine-Peptide Bioconjugate for Potential Theranostic Applications.

The functionalized, asymmetric fluoro-fluoroalkyl scaffold FHCOOHPcZn (3) was used to prepare FHCOOPcZn-6-amino-hexanoate-CTVALPGGYVRVC (5), a Pep42 peptide bioconjugate envisioned for photodynamic therapy, which can specifically target the GRP78 chaperone protein overexpressed and exclusively localized on some cancer cell surfaces. The analogous FHCOOHPcCu (4) has also been prepared, and its single-crystal X-ray structure was elucidated. Despite reduced steric hindrance relative to the nonfunctionalized, single-site complexes of the FPc scaffold, no aggregation was detected in solution via UV-vis spectroscopy, for either 3, 4, or 5, consistent with the lack of π stacking observed for the crystalline 4.

Photoreduction and light-induced triplet-state formation in a single-site fluoroalkylated zinc phthalocyanine.

Electron-withdrawing perfluoroalkyl peripheral substituents enhance the photosensitizing properties of metal phthalocyanines while increasing their solubility, thus providing opportunities for advanced characterization of their catalytically-relevant excited states. Optical absorption and electron paramagnetic resonance (EPR) spectroscopy experiments reveal that red light induces the reduction of perfluoroisopropyl-substituted zinc(ii) phthalocyanine (F64PcZn) dissolved in ethanol. A similar photoreduction does not occur in toluene.

An improved synthesis of 3,6-anhydro-D-glucal and a study of its unusual chemical reactivity.

6-O-Tosyl-d-glucal 1 upon treatment with excess LiAlH4 unexpectedly gave 3,6-anhydro-d-glucal 2 as a major product in good yield. A crystal structure was obtained. Reaction of the anhydride 2 with N-iodosuccinimide (NIS) in excess methanol resulted in the formation of diastereomeric 2-deoxy-2-iodoglycosides.

Chemically robust fluoroalkyl phthalocyanine-oligonucleotide bioconjugates and their GRP78 oncogene photocleavage activity.

The first representative of functionalized fluoroalkyl phthalocyanines, F48H7(COOH)PcZn, is reported. The complex generates (1)O2 affording long-lasting photooxidation of an external substrate without self-decomposition. The carboxylic group couples with an antisense oligonucleotide targeting GRP78 oncogenes, resulting in the F48H7PcZn-cancer targeting oligonucleotide (CTO).

Highly reduced double-decker single-molecule magnets exhibiting slow magnetic relaxation.

F64Pc2Ln (1Ln, Ln = Tb or Lu) represent the first halogenated phthalocyanine double-decker lanthanide complexes, and 1Tb exhibits single-molecule magnet properties as revealed by solid-state magnetometry. The fluorine substituents of the phthalocyanine rings have a dramatic effect on the redox properties of the F64Pc2Ln complexes, namely, a stabilization of their reduced states. Electrochemical and spectroelectrochemical measurements demonstrate that the 1Tb(-/2-) and 1Tb(2-/3-) couples exhibit redox reversibility and that the 1Tb(-), 1Tb(2-) and 1Tb(3-) species may be prepared by bulk electrolysis in acetone.

Time-resolved singlet oxygen luminescence detection under photodynamic therapy relevant conditions: comparison of ex vivo application of two photosensitizer formulations.

Singlet oxygen plays a crucial role in photo-dermatology and photodynamic therapy (PDT) of cancer. Its direct observation by measuring the phosphorescence at 1270 nm, however, is still challenging due to the very low emission probability. It is especially challenging for the time-resolved detection of singlet oxygen kinetics in vivo which is of special interest for biomedical applications.

Broadening the reactivity spectrum of a phthalocyanine catalyst while suppressing its nucleophilic, electrophilic and radical degradation pathways.

A robust molecule that resists degradation via nucleophilic, electrophilic and radical attacks is described. Coordinated O(2) is reduced catalytically, producing efficiently thyil radicals in spite of the extreme electronic deficiency of the catalyst.

Structures and redox characteristics of electron-deficient vanadyl phthalocyanines.

The first single-crystal X-ray structures of substituted vanadyl phthalocyanine materials reveal the high-valence vanadium ions (denoted as V(IV)), whose coordination by a highly electron-deficient ligand is facilitated by an axial oxo group. The metal center of the hydrophilic V═O core, encapsulated in F-rich hydrophobic pockets, reaches a coordination number of 6 by binding an additional H(2)O that, in turn, hydrogen-bonds with ketones, resulting in solvent-induced variable solid-state architectures. Fluoroalkyl (R(f)) ligand substituents hinder π-π stacking interactions and favor ordered long-range packing, as well as the facile formation of film materials that exhibit high thermal stability and oxidation resistance.

Synthesis, X-ray structure, magnetic resonance, and DFT analysis of a soluble copper(II) phthalocyanine lacking C-H bonds.

The synthesis, crystal structure, and electronic properties of perfluoro-isopropyl-substituted perfluorophthalocyanine bearing a copper atom in the central cavity (F(64)PcCu) are reported. While most halogenated phthalocyanines do not exhibit long-term order sufficient to form large single crystals, this is not the case for F(64)PcCu. Its crystal structure was determined by X-ray analysis and linked to the electronic properties determined by electron paramagnetic resonance (EPR).

Rational design of a reactive yet stable organic-based photocatalyst.

Zinc perfluoro-fluoroalkyl-phthalocyanine, synthesized in high yield, does not exhibit electron loss, does not aggregate in solution, is photostable and produces (1)O(2) in very high quantum yields. Aerobic photo-oxygenation of an external substrate occurs without catalyst self-oxidation. The encapsulation of a metal center in a refractory organic environment could guide the design of other viable catalysts for oxygenation of substrates either for synthesis or for oxidative destruction of organic or biological molecules, under reaction conditions that include the use of only air and light.

Long-range solid-state ordering and high geometric distortions induced in phthalocyanines by small fluoroalkyl groups.

Electron-withdrawing alpha-CF(3) groups sterically induce severe geometric distortions and long-range solid-state ordering in protio and catalytically active micro-oxo iron phthalocyanine.

Effects of tris(pyrazolyl)borato ligand substituents on dioxygen activation and stabilization by copper compounds.

Dinuclear [Cu2(mu-O)2(Tp(R,R')2] complexes, analogues of the active site of oxyhemocyanin, are theoretically studied, and the effect of the substituents of the tris(pyrazolyl)borate ligands, Tp(R,R'), is analyzed. Density functional theory calculations reveal that the type of bridging oxygen, peroxo, or bisoxo is strongly influenced by the nature and position of the R substituents because of variable substituent..

Enhanced acidity, photophysical properties and liposome binding of perfluoroalkylated phthalocyanines lacking C-H bonds.

The acid-base, spectroscopic, photophysical and liposome-binding properties of the recently synthesized free base, 29H,31H,1,4,8,11,15,18,22,25-octafluoro-2,3,9,10,16,17,23, 24-octakisperfluoro(isopropyl) phthalocyanine, F64PcH2, are reported. The perfluoroalkylation of the phthalocyanine core renders the hydrogen atoms acidic, with a pK(a) = 6. The F64Pc(-2) dianion is detected already at pH 3, by singular-value decomposition analysis of electronic spectra.

Effects of Peripheral Substituents on the Electronic Structure and Properties of Unligated and Ligated Metal Phthalocyanines, Metal = Fe, Co, Zn.

The effects of peripheral, multiple -F as well as -C2F5 substituents, on the electronic structure and properties of unligated and ligated metal phthalocyanines, PcM, PcM(acetone)2 (M = Fe, Co, Zn), PcZn(Cl), and PcZn(Cl(-)), have been investigated using a DFT method. The calculations provide a clear explanation for the changes in the ground state, molecular orbital (MO) energy levels, ionization potentials (IP), electron affinities (EA), charge distribution on the metal (QM), axial binding energies, and in electronic spectra. While the strongly electron-withdrawing -C2F5 groups on the Pc ring change the ground state of PcFe, they do not influence the ground state of PcCo.

Effects of peripheral substituents and axial ligands on the electronic structure and properties of iron phthalocyanine.

The effects of peripheral substituents and axial ligands on the electronic structure and properties of iron phthalocyanine, H(16)PcFe, have been investigated using a DFT method. Substitution by electron-withdrawing fluorinated groups alters the ground state of H(16)PcFe and gives rise to large changes in the ionization potentials and electron affinity. For the six-coordinate adducts with acetone, H(2)O, and pyridine, the axial coordination of two weak-field ligands leads to an intermediate-spin ground state, while the strong-field ligands make the system diamagnetic.

Spectroscopy and electronic structure of electron deficient zinc phthalocyanines.

The effect of introduction of perfluoro alkyl groups into phthalocyanines, as evidenced by the spectroscopic properties of 1,4,8,11,15,18,22,25-octa-fluoro-2,3,9,10,16,17,23,24-octa-perfluoro isopropyl zinc phthalocyanine, ZnF(64)Pc(-2) and its ring-reduced radical anion species, [ZnF(64)Pc(-3)](-), are reported. A combination of UV-visible absorption and magnetic circular dichroism (MCD) spectroscopy, ESI and MALDI-TOF mass spectrometry, cyclic and differential pulse voltammetry, and complete theoretical calculations using INDO/S and DFT techniques reveals that the substitution of all sixteen hydrogen atoms in protio ZnPc(-2) by eight F and eight i-C(3)F(7) groups red shifts the Q and pi --> pi transitions and narrows the HOMO-LUMO gap while simultaneously preventing ring photooxidation and stabilizing the radical anion. The [ZnF(64)Pc(-3)](-) species, which is in equilibrium in solution with the neutral complex when a reducing agent is present, is unusually stable.