Preparation and characterization of first optically active rigid phthalocyanine dimers

The first optically active rigid covalently linked by enantiomerically pure (R)- or (S)-BINOL metal-free phthalocyanine dimers have been prepared and characterized using electronic absorption, CD, MCD, MS, and NMR techniques as well as semi-empirical molecular orbital calculations.     

Chirality induction in binuclear phthalocyanine tweezers

A novel binuclear phthalocyanine tweezers, in which two zinc-phthalocyanine rings are linked to an optically active binaphthyl group through triazolyl linkages, was self-cyclized through triazolyl-to-zinc coordination bonds. An axially chiral S-binaphthyl group induced planar chirality in a slipped-cofacial stack of phthalocyanine moieties, and therefore displayed fluorescence with a good quantum yield (Φ_F = 0.23) and circularly polarized luminescence with a moderate intensity of dissymmetry factor (g_lum = −4 × 10⁻⁴) in the near-infrared wavelength region.     

Unusual self-assembled nanoaggregation of the thermally stable metal-free slipped-cofacial J-type phthalocyanine dimer

Nanoaggregation of the thermally stable bis(2-hydroxy-9(10),16(17),23(24)-tri-tert-butylphthalocyanine) of J-type was observed by the field emission scanning electron microscopy (FE-SEM). Ordered phases, represented as threads composed of about 200 nm diameter circles were discovered, unlike the parent dimeric magnesium complex, in which similar circles combine together to give visually distinguishable zones with widths of about 600 nm and the same distance between them.     

Synthesis of a transition-metalated phosphinoborane dimer

The unprecedented aggregate of a transition-metalated phosphinoborane was reported. Cp(CO)₂Fe{P(BCl₃)HPh} was treated with n-BuLi to yield the iron-phosphinoborane dimer, [Cp(CO)₂Fe{P(μ-BCl₂)Ph}]₂, via a dehydrohalogenation reaction. The X-ray structural study revealed that the dimer has a bent P₂B₂ 4-membered ring with two iron complex fragments in equatorial positions.     

Unexpected dimeric products from the amidomethylation of pentasubstituted benzenes

An isomeric series of unexpected diarylmethane products with flexible substituents, isolated from amidomethylation reactions of p-dimethoxybenzene derivatives, was analyzed by X-ray crystallography to reveal novel solid-state structures, two of which have identical elemental cell parameters.     

Hydrogen-bonded dimer can mediate supramolecular β-sheet formation and subsequent amyloid-like fibril formation: a model study

FT-IR data of six terminally blocked tripeptides containing Acp (ε-aminocaproic acid) reveals that all of them form supramolecular β-sheets in the solid state. Single crystal X-ray diffraction studies of two peptides not only support this data but also disclose the fact that the supramolecular β-sheet formation is initiated via dimer formation. The Scanning Electron Microscopic images of all peptides exhibit amyloid-like fibrils that show green birefringence after binding with Congo red, which is a characteristic feature of many neurodegenerative disease causing amyloid fibrils.     

Synthesis, structural investigation and thermal stability of aqua magnesium(II) phthalocyanine bis(diethylamine) solvate

Aqua magnesium phthalocyanine bis(diethylamine) complex was obtained in the crystalline form and its crystal structure was determined by single-crystal X-ray diffraction. The Mg atom is 4 + 1 coordinated by four N isoindole atoms and one O atom. The MgPc moiety is non-planar, the Mg(II) is deviated by 0.492(2) Å from the N₄-isoindole plane towards the oxygen atom of water molecule. The arrangement of MgPc(H₂O) and diethylamine molecules is determined by O–HN hydrogen bonds and π–π interactions. The complex is stable up to 140 °C. At this temperature the complex loses diethylamine molecules and next at 200 °C loses the water molecule and finally converts into β-MgPc.     

Synthesis and photosensitizing properties of fluoroalkoxyl phthalocyanine metal complexes

Nine fluoroalkoxyl phthalocyanine metal complexes (Zn, AlCl, Mg, Co, Cu, FeCl) were synthesized from 4-(polyfluoroalkoxyl) phthalic anhydride. The fat-soluble phthalocyanines were characterized by elemental analysis, IR, ¹H NMR and fast-atom-bombardment mass spectroscopy. Zinc and aluminum chloride complexes show higher photooxidation ability in solution containing 20% perfluorocarbons than in hydrocarbon solvents.     

The photodegradation of a zinc phthalocyanine

A water-soluble zinc phthalocyanine (Pc), ZnPc (3), bearing 12 dimethylamino groups, which enhance the solubility of the macrocycle was synthesized and characterized. Photobleaching of the compound was examined both in vivo and in vitro. Laser irradiation causes photo-oxidation of the newly synthesized ZnPc. A photobleachable phthalocyanine can be an alternative in imaging; phthalocyanine dyes are used in imaging the cardiovascular system. Besides, it can be used in fluorescein angiography in some cases. When compared to stable ones, a photobleaching ZnPc (3) might be an attractive compound for imaging in medicine.     

Density functional theory studies of N-protonation of the free base phthalocyanine

The structures and relative energies of twenty-two N-protonated species of the free base phthalocyanine (H₂Pc) have been systematically studied with the density functional theory at the B3LYP/6-31G(d) level of theory. The calculations demonstrated that the N-protonation tends to increase the N–C bonds and the C–N–C angles on the protonation sites. The inner protonation at the isoindole-nitrogen atoms causes significant out-of-plane deformation of the macrocycle, ascribed to the steric hindrance of the central cavity. The relative energies of various protonated species were calculated and compared to deduce the preferred sites for protonation. It was revealed that the outer protonation at the meso-nitrogen atoms is energetically more favorable than the inner protonation at the isoindole-nitrogen atoms. Among the studied twenty-two protonated species, the most stable one is H₆Pc⁴⁺(IS1), for which all the outer meso-nitrogen atoms are protonated. TDDFT calculations have been performed for selected species, and the results were used to analysis the UV–visible spectrum of the concentrated sulfuric acid solution of the free base phthalocyanine.     

Synthesis of phthalocyanine dimers,trimers, and oligomers bridged via phenyl groups

Several phthalocyanine dimers, trimers, and oligomers bridged via aryl (phenyl) groups were prepared using the Suzuki–Miyaura cross coupling reaction of phthalocyanine-boronate ester and various halide derivatives under palladium catalyst reaction conditions. Photophysical data reveal energy transfer between the Pc moieties resulting in the appearance of new red-shifted Q-bands. The shift and the nature of Q-band depend on the number of phenyl groups, the number of Pc, and the position of attachment on the phenyl ring.     

Unexpected formation and structural characterisation of a novel rhodium B12 analogue

The metalation reactions of the 2,2'-bidipyrrin 4 with different rhodium(I) precursors yield the complexes 5 and 6 and the unusual corrinoid 7, depending only on the type of the ancillary ligand employed.     

Dimers, trimers and oligomers of phthalocyanines and related compounds

Cofacial and planar homo- and heteroleptic dimers and oligomers of phthalocyanine (Pc) and its analogues reported to date have been reviewed.     

Unexpected simultaneous synthesis of trisubstituted quinolines and acylhydrazones under catalyst-free conditions

Trisubstituted quinolines and acylhydrazones were unexpectedly prepared from a reaction of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides with acetylenic esters. Using of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides led to obtain not only quinoline, but also a second pharmaceutical important product acylhydrazone. Notably, excellent yields, operational simplicity, short reaction times, and the avoidance of the use of catalysts make this approach an attractive complementary method to produce quinoline-2,3-dicarboxylates. The crystal structure of 5a was determined using single-crystal X-ray crystallography. The results showed that crystal packing diagram of 5a is of two pairs of molecules that have two independent alternate intermolecular 1D-polymeric H-bonds between two perpendicular molecules.     

Novel peripherally substituted zinc phthalocyanine: synthesis,characterization, investigation of photophysicochemical properties and theoretical study

The new thiohexanoic acid substituted zinc phthalocyanine was synthesized and characterized by FT-IR, ¹H–NMR, electronic spectroscopy, and mass spectrometry as well as DFT calculation studies. The photochemical properties (singlet-oxygen quantum yields and photodegradation quantum yields) and photophysical properties (fluorescence quantum yields and fluorescence behavior) of the compound were studied in dimethylsulfoxide (DMSO), dimethylformamide (DMF) and tetrahydrofuran (THF). Singlet-oxygen quantum yields ranged from 0.29 to 0.43. However, energy-minimized structure, vibrational frequency, electronic distribution and molecular orbitals were obtained by DFT calculations which were supported by experimental results.     

Development of a novel nucleoside analogue with S-type sugar conformation: 2′-deoxy-trans-3′,4′-bridged nucleic acids

Two novel trans-3′,4′-bridged nucleic acid (trans-3′,4′-BNA) monomers, one with a 3,5,8-trioxabicyclo[5.3.0]decane structure and the other with a 4,7-dioxabicyclo[4.3.0]nonane structure, were successfully synthesized from thymidine. The locked trans-fused ring structures of the nucleoside analogues were confirmed by X-ray crystallography, which also indicated that their furanose rings had a typical S-type conformation involving C_2′-endo or C_3′-exo sugar puckering, respectively, and the same ring conformation as that observed in the B-type helical structure of the DNA duplex.     

Investigated aerobic oxidation of aminochlorophenol catalyzed by phthalocyanine complexes

The synthesis of 9-Octadecenamide substituted Fe(II) phthalocyanine (ODAFePc) and Ni(II) phthalocyanine (ODANiPc) complexes from Fe(II) tetracarboxylic acid phthalocyanine (FeTcPc) and Ni(II) tetracarboxylic acid phthalocyanine (NiTcPc) with 9-Octadecenamide. These complexes have high molecular weight and soluble in organic solvents. The complexes have been confirmed by FTIR, Mass spectroscopy, UV–Visible X-ray diffraction, and thermogravimetric analysis. The synthesized complexes exhibit excellent stability and are catalytically active in 2-amino-4-chlorophenol (ACP) oxidation. The new method was used for the determination of the oxidation of phenol by applying different experimental parameters like concentration, catalytic quantity, temperature, and pH to get a good yield and catalytic activity of ODAFePc and ODANiPc were studied. ACP was oxidized by dissolved oxygen with ODAFePc and ODANiPc as a catalyst and immediately combined with 4-aminoantipyrine (4-AAP) to form a pink dye and was determined by appearance of absorption intensity at 580 ​nm. All the experimental results show that ODAFePc and ODANiPc complexes exhibit good catalytic behavior on oxidation of 2-amino-4-chlorophenol.     

Octaalkylphthalocyaninato ruthenium(II) complexes with mixed axial ligands and supramolecular porphyrin:phthalocyanine structures derived from them

Complementary syntheses of 1,4,8,11,15,18,22,25-octakis(alkyl) substituted ruthenium phthalocyanines, in which either one or two axial ligands can be added, are described. Their utility in the preparation of further (pyridyl) ligated derivatives has been shown to be straightforward. The chemistry is sufficiently robust and efficient to permit elaborate, supramolecular complexes to be prepared, as demonstrated by the synthesis of porphyrin-phthalocyanine multichromophore arrays.     

Exact dimer statistics and characteristic polynomials of cacti lattices

Summary The pruning method developed earlier by one of the authors (K.B.) combined with the operator method is shown to yield powerful recursive relations for generating functions for dimer statistics and characteristic polynomials of cacti graphs and cacti lattices. The method developed is applied to linear cacti, Bethe cacti of any length containing rings of any size, and cyclic cacti of any length and size. It is shown that exact dimer statistics can be done on any cactus lattice.Dedicated to Professor V. Krishnamurthy on the occasion of his 60th birthdayAlfred P. Sloan fellow; Camille and Henry Dreyfus teacher-scholar