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In this study, the effects of incorporation of halogen atoms at different positions and dimerization on the photophysical properties of the aza-BODIPYs were investigated. Aza-BODIPY derivative carrying chlorine atoms on the para-position of the distal phenyl groups (4) and its core-brominated analogue (5) were prepared to establish the external and internal heavy atom effects. Dimerization of aza-BODIPY 4 through oxidative homocoupling with FeCl3 yielded the target homonuclear aza-BODIPY dimer (6). All of the aza-BODIPY derivatives prepared in this study were fully characterized by using UV–Vis, Fluorescence, NMR (1H, 13C, 11B and 19F), Mass and X-Ray spectroscopy techniques. The photophysical properties were fully characterized and compared to those of the tetra-phenyl aza-BODIPY derivative (A). Singlet oxygen generation experiments were also performed. The aza-BODIPY derivative possessing bromine atoms at the central core displayed the utmost efficiency for singlet oxygen generation.

A novel zinc(II) phthalocyanine substituted with four diphenylborinic ester units was synthesized by the reaction of 2,9,16,23-tetra (salicylaldimino)-phthtalocyaninatozinc(II) and triphenylborane in THF at reflux condition. The novel zinc phthalocyanine was characterized by using elemental analysis, IR, H-1 and 11B-NMR and UV-Vis spectral data. B-11-NMR data demonstrated that the boron atom is in tetracoordinated state and diphenylborinate substituents have a cyclic structure with a coordinative N-B bond enhancing the stability of this borinated phthalocyanine derivative. Moreover, the consequences of the presence of diphenylborinic ester groups on the spectral, photophysical and photochemical properties of the new zinc phthalocyanine are investigated in detail. (c) 2014 Elsevier B.V. All rights reserved.

Metal-free and metallophthalocyanines carrying four dendritic 3,4-bis(benzyloxy)benzyloxy groups on the periphery were prepared by cyclotetramerization of a new precursor, namely 4-[3,4-bis(benzyloxy)benzyloxy]phthalonitrile (2) in the presence of the corresponding divalent metal salts (Zn(II), Co(II)). The novel phthalonitrile derivative 2 was synthesized by the reaction of 4-nitrophthalonitrile and 3,4-dibenzyloxybenzyl alcohol (1), which was prepared by the catalytic reduction of 3,4-dibenzyloxybenzaldehyde with NaBH4 in ethanol. The new compounds were characterized by elemental analysis, together with FT-IR, 1H NMR and UV–Vis spectra. The electrochemical and in situ spectroelectrochemical measurements showed that while the cobalt phthalocyanine complex (5) gives both metal-based and ring-based redox processes, the metal-free and zinc phthalocyanine complexes (3 and 4) give only ring-based electron transfer processes. An in situ electrocolorimetric method was applied to investigate the colour of the electrogenerated anionic and cationic forms of the novel phthalocyanine complexes carrying bulky ethereal aryloxy substituents.

4-(4-Formyl-3-hydroxyphenoxy)phthalonitrile (3) and its condensation product with 2-aminophenol have been synthesized to reach 4-(3-hydroxy-4-(((2-hydroxyphenyl) imino)-methyl) phenoxy) phthalonitrile (5), a tridentate ligand possessing ONO binding sites. Subsequent condensation of phenylboronic acid with 5 afforded a novel boronic ester of a Schiff base with a phthalonitrile group (7). Boronate 7 displays high stability and can be handled in air due to the presence of coordinative B-N and covalent B-O bonds in its structure. The novel compounds were characterized by elemental analyses, IR, UV-vis, mass, H-1-, C-13- and B-11 NMR spectra. (C) 2011 Elsevier B.V. All rights reserved.

The recent advances in the synthesis of carborane and boronic ester-substituted tetrapyrroles (porphyrins, porphyrazines, and phthalocyanines) are reviewed together with their possible utilization as agents for photodynamic therapy (PDT) and boron neutron capture therapy of cancer (BNCT) as well as dual PDT/BNCT sensitizers.

The recent advances in the synthesis of carborane and boronic ester-substituted tetrapyrroles (porphyrins, porphyrazines, and phthalocyanines) are reviewed together with their possible utilization as agents for photodynamic therapy (PDT) and boron neutron capture therapy of cancer (BNCT) as well as dual PDT/BNCT sensitizers.

With the aim of preparing a novel Zn phthalocyanine bearing four phenylboronic azaester substituents at peripheral positions, 4(2-(bis(2-hydroxyethypamino)ethoxy]phthalonitrile (2) was synthesized by the aromatic nucleophilic substitution reaction of 4-nitrophthalonitrile with triethanolamine. 2,9(10),16(17),23(24)-Tetrakis-[2-(bis( hydroxyethyl)amino)ethoxy]-phthalocyaninatozinc (II) (4) was prepared from the cyclotetramerization of dinitrile 2 in the presence of anhydrous zinc(II) acetate by microwave irradiation. Alternatively, treatment of 2 with phenylboronic acid yielded the phenylboronic azaester (3), namely 4-(2-(2-phenyl-1,3,6,2-dioxazaborocan-6-ypethoxy)phthalonitrile. Treatment of phthalocyanine 4 with phenylboronic acid in a mixture of DMSO/toluene (20/1, v/v) afforded the desired phthalocyanine 5. The novel compounds were characterized by elemental analyses, IR, UV-Vis, H-1, C-13 and B-11 NMR spectra. The B-11 NMR data indicated that the boron atom of phthalonitrile 3 is in the tetra-coordinated state with the formation of a coordinative N-B bond (closed form), while in the case of phthalocyanine 5, the open conformer possessing a tricoordinated B atom is favoured. (C) 2012 Elsevier Ltd. All rights reserved.

Phenylboronic acid esters of an unsaturated precursor 1,2-dicyano-1,2-bis(2-hydroxy- ethylthio)ethylene and the magnesium porphyrazine derived from it have been prepared either by refluxing a mixture of the reagents in chloroform in the presence of molecular sieve or by solvent-free heating in an oven under reduced pressure. The two novel compounds have been characterized by elemental analysis together with ultraviolet-visible, infrared spectroscopy, proton nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, boron-11 nuclear magnetic resonance, and mass spectra.