Synthesis of an octasubstituted galactose zinc(II) phthalocyanine

4,5-Bis(1,2:3,4-di-O-isopropylidene-α-d-galactopyranos-6-yl)phthalonitrile (3) was prepared by S_NAr reaction of diacetone galactose 1 and 4,5-difluorophthalonitrile (2) in 96% yield. Cyclotetramerization of 3 was achieved via its isoindoline derivative 4, affording the peripherally octasubstituted galactose zinc(II) phthalocyanine 5 in 29% yield. Deprotection of 5 gave the highly water soluble octasubstituted galactose zinc(II) phthalocyanine 6 in 81% yield which will be applied as a photosensitizer in photodynamic therapy.     

Synthesis,characterization and electrochemical properties of novel metal free and zinc(II) phthalocyanines of ball and clamshell types

The phthalodinitrile derivative 1 was prepared by the reaction of 4-nitrophthalonitrile and 1,3-dimethoxy-4-tert-butylcalix[4]arene in dry dimethylsulfoxide as the solvent, in the presence of the base K₂CO₃, by nucleophilic substitution of an activated nitro group in an aromatic ring. The tetramerization of compound 1 gave a binuclear zinc(II) phthalocyanine and a metal-free phthalocyanine of the ball type, 2 and 3, respectively. Its condensation with 4,5-bis(hexylthio)phthalonitrile results in a binuclear phthalocyanine of the clamshell type, 4. The newly synthesized compounds were characterized by elemental analysis, UV–Vis, IR, MS and ¹H NMR spectra. The electronic spectra exhibit an intense π → π^∗ transition with characteristic Q and B bands of the phthalocyanine core. The electrochemical properties of 2–4 were examined by cyclic voltammetry in non-aqueous media. The voltammetric results showed that while there is no considerable interaction between the two phthalocyanine rings in 4, the splitting of a molecular orbital occurs as a result of the strong interaction between the phthalocyanine rings in 2 and 3.     

Synthesis, photophysical and thermal studies of symmetrical and unsymmetrical zinc phthalocyanines

The novel zinc phthalocyanine (3) with malonylester and chloro groups on each benzo unit was synthesized from 4-diethoxymalonyl-5-chloro-phthalonitrile (1). The unsymmetrically substituted zinc phthalocyanine (5), carrying hexylthio, malonylester and chloro groups at the periphery, was obtained from 4-diethoxymalonyl-5-chloro-phthalonitrile (1) and 4,5-bis-hexylsulfanyl-phthalonitrile (2) by a statistical condensation method as an A₃B type unsymmetrical phthalocyanine compound. Transesterification of the malonyl esters of the new symmetrical and unsymmetrical phthalocyanines occurred during the cyclotetramerization of dinitriles with Zn(CH₃COO)₂ in 1-pentanol in the presence of DBU. Octa-hexylthio-substituted zinc phthalocyanine (4) was prepared according to the literature. The photophysical and thermal properties of all the phthalocyanine complexes are described for the first time. These novel symmetrical and unsymmetrical phthalocyanine macrocycles have been characterized by a series of spectroscopic methods including ¹H NMR, electronic absorption, IR and mass spectroscopy, in addition to elemental analysis. Their narrow long wavelength absorption band shows that the bulky substituents on the periphery prevent aggregation. The unsymmetrically substituted phthalocyanine (5) gave a greater fluorescence quantum yield in chloroform than the symmetrical analogues (3 and 4).     

Synthesis and structural characterization of novel zinc(II) and cadmium(II) complexes with pyridine-phosphine chalcogenide ligands

New pyridine-phosphine chalcogenide ligands, tris[2-(2-pyridyl)ethyl]phosphine sulfide 1a and tris[2-(2-pyridyl)ethyl]phosphine selenide 1b, react with zinc(II) and cadmium(II) chlorides in EtOH at room temperature to afford complexes of compositions 2ZnCl₂·2L (2, L = 1a) and 3CdCl₂·2L (3a,b, L = 1a,b) in high yields. The solid-state structure of complexes 2, 3 has been proved by X-ray analysis data. Complex 2 is a centrosymmetric dimer, where two atoms of zinc are bonded by two bridging pyridine-phosphine sulfide ligands through N atoms. Complexes 3a,b exist as polymeric chains with each bridging ligand acting as a chelate N,S- or N,Se-donor to one cadmium(II) center and as a pyridine N-donor to the next cadmium(II) center.     

Synthesis,characterization and electrochemistry of a new organosoluble metal-free and metallophthalocyanines

4-[2-(Phenylthio)ethoxy]phthalonitrile 3 was synthesized by nucleophilic displacement of nitro group in 4-nitrophthalonitrile with 2-(phenylthio)ethanol 1. The metal-free phthalocyanine 4 was prepared by the reaction of a dinitrile monomer with 2-(dimethylamino)ethanol. Ni(II), Co(II), Cu(I) phthalocyanines 5, 7, 8 were prepared by reaction of the dinitrile compound with the chlorides of Ni(II), Co(II), Cu(I) in DMAE. Zn(II) phthalocyanine 6, was prepared by reaction of the dinitrile compound with the acetates of Zn(II) in DMAE. Electrochemical behaviours of novel metal-free, Co(II) and Zn(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry techniques. The new compounds were characterized by a combination of IR, ¹H NMR, ¹³C NMR, UV–Vis, elemental analysis and MS spectral data.     

Gas-phase CT-stabilized Ag(I) and Zn(II) metal-organic complexes - Experimental versus theoretical study

A series of 14 new metal-organic compounds of Ag(I) and Zn(II), i.e. trichloro(1-(2-hydroxyethyl)piperazinium)zinc(II) (1), 1-[2-(2-hydroxyethoxy)-ethyl]-piperazinium tetrachlorozincate(II) (2), tetrachlorozincate(II) salt of 4-(2-aminoethyl)morpholine (3), 1,4-bis(2-hydroxyethyl)piperazinium tetrachlorozincate(II) (4), 5-sulfosalicylate coordination polymer of Ag(I) (5) [3dd], mandelate coordination polymer of Ag(I) (6) [1r], hexa-aqua zinc(II) 5-sulfosalicylate monohydrate (7), cyclic quaternary N-ethylmorpholine tetrachlorozincate(II) monohydrate (8), 2,2′:6′,2″-terpyridinium tetrachlorozincate(II) (9), bis(guaninium) tetrachlorozincate(II) dihydrate (10), bis(8-hydroxyquinolinium) tetrachlorozincate(II) (11), zinc(II) complexes of 2,4-dihydroxy-(12) and 2,3-dihydroxy-(13) benzoic acid, silver(I) complex of 2,4-dihydroxybenzoic acid (14), as well as cyclic quaternary N-ethylmorpholine chloride monohydrate (8a), are synthesized, isolated spectroscopic and structurally characterized by the mass spectrometry, electronic absorption and vibrational spectroscopy, diffuse reflectance and fluorescence spectroscopy in condense phases, single crystal X-ray diffraction, ICP and thermal methods. Quantum chemical DFT calculations, including NBO analysis are performed for all of the obtained complexes, their ligands as well as series of structurally related model metal-organic chromophores. The obtained correlation dependences between the theoretical and experimental structural and spectroscopic data both in gas- and condense phases, underlying an explanation of the experimentally observed mass spectrometrically stable metal-organic species in the gas phase as well as the atypical CT bands in excited state.     

Synthesis and properties of crown ether functionalized coumarin substituted zinc phthalocyanine

The novel 6,7-[15-crown-5]-3-[p-(2,3-dicyanophenoxy)phenyl]coumarin (1) and its non-peripherally substituted zinc phthalocyanine complex (2) have been prepared and characterized by elemental analysis, ¹H NMR (for compound 1), MALDI-TOF, FT-IR and UV-Vis spectral data. Fluorescence intensity changes of compound 1 have been determined by addition of Na⁺ or K⁺ ions at 25 °C in THF. The effects of the chromenone crown ether substituent of the phthalocyanine molecule on the photophysical (fluorescence quantum yield and lifetime) and photochemical (singlet oxygen generation and photodegradation) properties were also investigated. The fluorescence of the zinc phthalocyanine complex is effectively quenched by addition of 1,4-benzoquinone (BQ).     

Synthesis, characterization, spectroscopic and electrochemical properties of phthalocyanines substituted with four 3-ferrocenyl-7-oxycoumarin moieties

The synthesis, spectroscopic and electrochemical properties of the tetra-(3-ferrocenyl-7-oxycoumarin)-substituted zinc (II) and cobalt (II) phthalocyanines (3 and 4) are reported for the first time. The synthesis of novel 3-ferrocenyl-7-hydroxycoumarin (1) was performed according to Perkin reaction, and the ligand, 7-(3,4-dicyanophenoxy)-3-ferrocenylcoumarin (2), was synthesized by the reaction of 3-ferrocenyl-7-hydroxycoumarin with 4-nitrophthalonitrile in the presence of K₂CO₃ as the base in dry dimethylformamide. The preparation of the corresponding zinc (II) and cobalt (II) metallo phthalocyanines (3 and 4) substituted with 3-ferrocenyl-7-oxycoumarin moieties at β-positions of the phthalocyanine ring was achieved by the cyclotetramerization of the coumarin ligand (2) with relevant metal(II) acetates in dry 2-dimethylaminoethanol. The new compounds have been characterized by elemental analyses, FT-IR, ¹H NMR, Mass and electronic spectroscopy. The fluorescence property of the zinc metallo phthalocyanine (3) is strongly affected by the presence of ferrocenyl moiety. The ferrocenyl moieties were very efficient in quenching the excited state of 3, which show very poor fluorescent intensity. The electrochemical properties of the complexes were also investigated by cyclic and differential pulse voltammetry techniques in non-aqueous medium. It was found that the redox-active ferrocene substituents are reduced concurrently at one potential.     

New olefinic centred binuclear clamshell type phthalocyanines: Design, synthesis, structural characterisation, the stability and the change in the electron cloud at olefine-based symmetrical diphthalonitrile fragment by the combined application of UV–Vis electronic structure and theoretical methods

The olefinic centred Schiff base (3) was obtained from the condensation of substituted dialdehyde (1) with 2-amino-4-methylphenol (2) in a 1:2 ratio. The diphthalonitrile derivative (5) was prepared by the reaction of 4-nitrophthalonitrile (4) and compound (3) in dry dimethylformamide/potassium carbonate. The key product (5) was obtained by nucleophilic substitution of an activated nitro group into an aromatic ring. The cyclotetramerization of compound (5) with phthalonitrile (6) in 1:6.15 ratio gave the expected metal-free phthalocyanine of clamshell type (7), and with metal salts of Zn(II), Ni(II), Co(II) and Cu(II) gave metallophthalocyanines of clamshell types (8-11), respectively in dimethylaminoethanol/1,8-diazabycyclo[5.4.0]undec-7-ene system. The products were purified by several techniques such as crystallization and preparative thin layer chromatography. The newly prepared compounds were characterised by a combination of elemental analyses, IR, ¹H/¹³C NMR, MS and UV-Vis spectroscopy.     

Synthesis and spectral characterization of zinc(II) complexes of N(4)-substituted thiosemicarbazone derived from salicylaldehyde: Structural study of a novel –OH free Zn(II) complex

Five novel zinc(II) complexes of salicylaldehyde 3-hexamethyleneiminyl thiosemicarbazone were synthesized and physico-chemically characterized. The complexes were given the formulae [Zn(HL)₂] (1), [Zn(L)py] (2), [Zn(L)bipy] · 3.5H₂O (3), [Zn(L)phen] · H₂O (4) and [Zn(L)γ-pic] (5). The thiosemicarbazone binds the metal as a dianionic ONS donor ligand in all the complexes, except in 1. Compound 1 is a homoleptic complex with zinc occupying the center of a distorted tetrahedral environment and being coordinated by two azomethine nitrogen and two thiolate sulfur atoms.     

New long-chain-substituted polymeric metal-free and metallophthalocyanines by microwave irradiation: Synthesis and characterization

A tetranitrile monomer N,N-bis{2-[2-(3,4-dicyanophenoxy)ethoxy]ethyl}-4-methylbenzenesulfonamide (3) was synthesized by nucleophilic aromatic substitution of N,N-bis[2-(2-hydroxyethoxy)ethyl]-4-methylbenzenesulfonamide (1) onto 4-nitrophthalonitrile (2). The metal-free phthalocyanine polymer (4) was prepared by the reaction of a tetranitrile monomer 3 in 2-(dimethylamino)ethanol. Ni(II), Co(II) and Cu(II) phthalocyanine polymers were prepared by the reaction of the tetranitrile compound with the chlorides of Ni(II), Co(II) and Cu(II) in 2-(dimethylamino)ethanol (DMAE). The Zn(II)-phthalocyanine polymer was prepared by the reaction of the tetranitrile compound with the acetate of Zn(II) in DMAE. The new compounds were characterized by a combination of IR, ¹H NMR, ¹³C NMR, UV–Vis, elemental analysis and MS spectral data.     

Preparation of 5-amino-6-oxo-1,6-dihydro[1,2,4]triazine-3-carboxylic acid derivatives and synthesis of compound libraries thereof

Treatment of [1,3,5]triazine-2,4,6-tricarboxylic acid triethyl ester (4) with arylhydrazines provided 5-amino-6-oxo-1,6-dihydro[1,2,4]triazine-3-carboxylic acid ethyl esters 5a-g in moderate to good yields. Hydrolysis under basic conditions gave the corresponding free carboxylic acids 6a-d. Despite the relatively high number of heteroatoms present the amido as-triazine compounds 6a-d showed good solubility in phosphate buffer as determined by a lyophilization solubility assay. Building block 5a served as starting point for the syntheses of two discrete exocyclic 5-amido and 3-amido compound libraries 7 and 8, respectively.     

Seven membered ring chelates derived from γ-hydroxyamides and triphenyltin or diphenylboron

N-Benzyl-4-hydroxy-butyramide (1), 4-hydroxy-N-[(R)-1-phenyl-ethyl]-butyramide (2), and (R)-4-hydroxy-2-methyl-N-[(R)-1-phenyl-ethyl]-butyramide (3a) were used to prepare new diphenylboron and triphenyltinoxy compounds: diphenylborinic acid 3-benzylcarbamoyl-propyl ester (4), diphenylborinic acid 3-[(R)-1-phenyl-ethylcarbamoyl]-propyl ester (5) and diphenylborinic acid (R)-3-[(R)-1-phenyl-ethylcarbamoyl]-butyl ester (6), N-benzyl-4-triphenyltinoxy-butyramide (7), 4-triphenyltinoxy-N-[(R)-1-phenyl-ethyl]-butyramide (8), and (R)-4-triphenyltinoxy-2-methyl-N-[(R)-1-phenyl-ethyl]-butyramide (9). The X-ray diffraction analysis of a crystalline structure of the new γ-hydroxyamide 3a is reported, as well as that of the first example of a crystalline structure where a diphenylborinic ester forms a seven membered chelate, by a carbonyl coordination to boron (4). Structural studies of tin and boron esters were performed by NMR. The CO internal coordination to tin atoms, affording seven membered rings, was observed by ¹¹⁹Sn NMR experiments at low temperature.     

Synthesis and properties of novel methanofullerenes having ethylthienyl and/or n-pentyl group for photovoltaic cells

Novel methanofullerenes 3 having ethylthienyl and/or n-pentyl groups were designed and synthesized for the purpose of developing new acceptors for an organic photovoltaic cell with higher performance than that of the [6,6]-phenyl-C₆₁-butylic acid methyl ester (PCBM) used as the standard acceptor. The electronic absorption spectra and cyclic voltammetry (CV) of 3, PCBM, and [6,6]-(thiophene-2-yl)-C₆₁-butylic acid methyl ester (ThCBM) were measured to estimate solubility and reduction potentials as characteristics of n-type semiconductor for organic photovoltaic devices. The CV measurements revealed reversible reduction waves for all of the methanofullerenes and the first reduction potentials of the n-pentyl-substituted 1-(5-ethylthiophene-2-yl)-[6,6]-methanofullerene[60] (3b) and 1-phenyl-[6,6]-methanofullerene[60] (3c) were negatively shifted compared to those of the corresponding terminal methyl ester-substituted homologues (3a and PCBM). The performances of photovoltaic devices consisting of 3b and 3c were slightly higher than those of PCBM.     

Cobalt(II), nickel(II) and zinc(II) coordination compounds derived from aromatic amines

The structural and spectroscopic characterization of coordination compounds of four aromatic amines derived from benzimidazole, 2-aminobenzimidazole (L1), 1-(S-methylcarbodithioate)-2-aminobenzimidazole (L2), 2-(2-aminophenyl)-1H-benzimidazole (L3) and 6,6-dimethyl-5H-benzimidazolyl[1,2-c]quinazoline (L4) are reported. Cobalt(II) [Co(L1)₂(CH₃COO)₂] (1) and nickel(II) [Ni(L1)₂(CH₃COO)₂] (2) acetate coordination compounds of L1 are discussed. The synthesis and the X-ray crystal structure of the new 1-(S-methylcarbodithioate)-2-aminobenzimidazole (L2) is informed, together with its cobalt(II) [Co(L2)₂Cl₂] (3), [Co(L2)₂Br₂] (4) and zinc(II) [Co(L2)₂Cl₂] (5), [Zn(L2)₂Br₂] (6) coordination compounds. In these compounds the imidazolic nitrogen is coordinated to the metal center, while the ArNH₂ and the S-methylcarbodithioate groups do not participate as coordination sites. A co-crystal of L1 and L2 is analyzed. Structural analyses of the coordination compounds of L3 showed that this ligand behaves as a bidentate ligand through the aniline and the imidazole groups forming six membered rings in the cobalt(II) [Co(L3)Cl₂] (7) and zinc(II) [Zn(L3)Cl₂] (8) compounds, as well as the nickel(II) nitrate [Ni(L3)₂(H₂O)₂](NO₃)₂ (9). The quinazoline L4 was produced by insertion of one acetone molecule and water elimination in L3, its X-ray crystal diffraction analysis, as well as that of its zinc(II) coordination compound [Zn(L4)₂Cl₂] (10), are discussed.     

Synthesis of 2-azaspiro[4.4]nonan-1-ones via phosphine-catalysed [3+2]-cycloadditions

The phosphine-catalyzed [3+2]-cycloaddition of the 2-methylene γ-lactams 4 and 5 and the acrylate 6 with the ylides derived from the ethyl ester, the amide or the chiral camphor sultam derivative of 2-butynoic acid (7a-c) give directly, or indirectly after reductive cyclization, spiro-heterocyclic products. The acid 32 underwent Curtius rearrangement and then acid hydrolysis to give two novel spiro-cyclic ketones, 41 and 42.     

Synthesis and characterization of metal-free and metallophthalocyanines containing N2S2-type macrocyclic moieties linked ferrocenyl groups

The new metal-free (4) and metallophthalocyanines (5) carrying macrocyclic moieties linked ferrocenyl groups have been synthesized by direct cyclotetramerization of the pre-cursor, 12,13-dicyano-4,7-bis(ferrocenylmethyl)-2,3,4,5,6,7,8,9-octahydrocyclobenzo[k]-4,7-diaza-1,10-dithiacyclododecine (3) which has been prepared by the macrocyclization reaction of 1,2-bis(2-iodoethylmercapto)-4,5-dicyanobenzene (1) with N,N′-ethylenebis-(ferroceneylmethyl)amine (2), in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a strong organic base. Nickel (II) phthalocyanine (5) was synthesized by the reaction of metal-free phthalocyanine with anhydrous NiCl₂ in dry quinoline. The target compound and its intermediates have been characterized by a combination of elemental analysis and ¹H, ¹³C NMR, IR, UV-Vis and MS spectral data.     

Synthesis, characterization and comparative studies on the photophysical and photochemical properties of metal-free and zinc(II) phthalocyanines with phenyloxyacetic acid functionalities

The synthesis and characterization of new peripherally and non-peripherally tetra-substituted metal-free and zinc(II) phthalocyanines with 2-, 3- and 4-phenyloxyacetic acid functionalities are described for the first time in this study. The new compounds have been characterized by elemental analysis, FT-IR, UV-Vis, MALDI-TOF and ¹H-NMR spectra. Photodegradation, singlet oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds are studied in dimethylformamide (DMF). The influence of the substituent position on the phthalocyanine framework (non-peripherally or peripherally), central metal ion (metal-free or zinc) and the position of the COOH group (2-, 3- or 4-position on the phenyloxyacetic acid) on the spectroscopic, photophysical and photochemical properties have been investigated. Non-peripherally zinc(II) phthalocyanines (1b and 2b) and peripherally zinc(II) phthalocyanine (4b) gave good singlet oxygen quantum yields (Φ_Δ) (0.37, 0.39 and 0.38, respectively) which indicate the potential of the complexes as photosensitizers in applications of PDT.     

Synthesis, photophysical and photochemical properties of highly soluble phthalocyanines substituted with four 3,5-dimethylpyrazole-1-methoxy groups

The synthesis and characterization of new peripherally tetra-3,5-dimethylpyrazole-1-methoxy substituted metal-free (4), zinc (5), nickel (6), cobalt (7), copper (8) and lead (9) phthalocyanines are described for the first time in this study. The photophysical (fluorescence quantum yields and fluorescence lifetimes) and photochemical (photodegradation and singlet oxygen quantum yields) properties of metal-free (4), zinc (5) and lead (9) phthalocyanines are studied in dimethylsulfoxide (DMSO). Nickel (6), cobalt (7) and copper (8) phthalocyanines (6-8) did not evaluate for this purpose due to transition metal and paramagnetic behavior of central metals in the phthalocyanine cavity. The fluorescence quenching behavior of metal-free (4), zinc (5) and lead (9) phthalocyanines are also investigated. The fluorescence emissions of these phthalocyanines are effectively quenched by 1,4-benzoquinone in DMSO.     

Synthesis of heterocyclic methylenebisphosphonates by 1,3-dipolar cycloaddition of ethyl diazoacetate to 1,2-benzoxaphosphorin-3-phosphonates

Reaction of salicylaldehydes with tetraethyl ester of methylenebisphosphonic acid, under Knoevenagel reaction conditions, gives the corresponding 1,2-benzoxaphosphorin-3-phosphonates 5 in good yields. The [3+2] regio- and stereoselective cycloaddition of 5a and 5b with ethyl diazoacetate gives two P-4 epimers of the corresponding pyrazoline bisphosphonate tetraethyl esters 9 and 10. Analogously, ethyl diazoacetate reacts with 1 and 2 to give the expected pyrazolines 6-8. The structures of the new compounds are revealed and confirmed by analytical, spectroscopic data and X-ray crystallographic analysis.