Synthesis,Characterization, Aggregation Properties,Antioxidant and Antimicrobial Activity of Novel Unmetalled and Metallophthalocyanines Bearing Coumarin Derivatives

In this study, novel Metal–free and metallophthalocyanines 3–10 were prepared by the cyclotetramerization of the new phthalonitriles 1–2 and the corresponding divalent metal salts. The novel phthalonitrile derivatives 1–2 were synthesized by the reaction between 4‐nitrophthalonitrile with 3‐hydroxycoumarin and 7‐hydroxycoumarin respectively in DMF in the presence of dry K₂CO₃ as base catalyst. The aggregation behavior of these compounds was investigated in different concentrations of DMSO for the Zn and Co phthalocyanines 5 , 9. In vitro antioxidant test method, namely diphenylpicrylhydrazyl radical scavenging activity, was used to determine the antioxidant activity of complexes 5–10 . In addition, these compounds were analyzed for their antibacterial activity against some bacteria by using the disk‐diffusion method. The compounds were characterized by spectral data (IR, UV–Vis, ¹H‐NMR and mass spectroscopies) as well as elemental analysis.     

Synthesis,characterization and catalytic activity of novel Co(II) and Pd(II)‐perfluoroalkylphthalocyanine in fluorous biphasic system; benzyl alcohol oxidation

Tetrakis[heptadecafluorononyl] substituted phthalocyanine complexes were prepared by template synthesis from 4‐(heptadecafluorononyloxy)phthalonitrile with Co(CH₃COO)^·₂H₂O or PdCl₂ in 2‐N, N‐dimethylaminoethanol. The corresponding phthalonitrile was obtained from heptadecafluorononan‐1‐ol and 4‐nitrophthalonitrile with K₂CO₃ in DMF at 50 °C. The structures of the compounds were characterized by elemental analysis, FTIR, UV–vis and MALDI‐TOF MS spectroscopic methods. Metallophthalocyanines are soluble in fluoroalkanes such as perfluoromethylcyclohexane (PFMCH). The complexes were tested as catalysts for benzyl alcohol oxidation with tert‐butylhydroperoxide (TBHP) in an organic–fluorous biphasic system (n‐hexane–PFMCH). The oxidation of benzyl alcohol was also tested with different oxidants, such as hydrogen peroxide, m‐chloroperoxybenzoic acid, molecular oxygen and oxone in n‐hexane–PFMCH. TBHP was found to be the best oxidant for benzyl alcohol oxidation since higher conversion and selectivity were observed when this oxidant was used. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and characterization of new metal-free and metallophthalocyanines fused α-methylferrocenylmethoxy units

Synthesis of metal-free and metallophthalocyanines bearing α-methylferrocenylmethoxy units was described. Precursor 3 required for the preparation of phthalocyanines 4–9, was synthsized by the nucleophilic aromatic substitution reaction between α-methylferrocenylmethanol and 4-nitrophthalonitrile in dry DMF. The metal-free phthalocyanine 4 was prepared from 4-(α-methylferrocenylmethoxy)phthalonitrile 3 in 1-pentanol with a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Metallophthalocyanines (M = Zn, Cu, Co, Ni and Pb) were prepared by cyclotetramerization reaction of phthalonitrile with appropriate materials. The phthalonitrile, metal-free and metallophthalocyanines were characterized by ¹H and ¹³C NMR, FT-IR UV–Vis and mass spectral data, as well as elemental analyses, which were consistent with the proposed structures.     

Synthesis,electrochemical, in situ spectroelectrochemical and in situ electrocolorimetric characterization of new metal-free and metallophthalocyanines substituted with 4-{2-[2-(1-naphthyloxy)ethoxy]ethoxy} groups

The synthesis of novel metal-free and metallophthalocyanines [Ni(II), Zn(II), Co(II), Cu(II)] were prepared by cyclotetramerization of a novel 4-{2-[2-(1-naphthyloxy)ethoxy]ethoxy}phthalonitrile and the corresponding metal salts (NiCl₂, Zn(CH₃COO)₂, CoCl₂ and CuCl₂). The structures of the target compounds were confirmed using elemental analysis, IR, ¹H NMR, ¹³C NMR, UV–Vis and MS spectral data. Voltammetric and in situ spectroelectrochemical measurements show that while cobalt phthalocyanine complex gives both metal-based and ring-based redox processes, metal-free, and zinc phthalocyanines show only ring-based reduction and oxidation processes. All complexes decomposed and coated on the electrode as nonconductive film at positive potential window of the electrolyte. An in situ electrocolorimetric method has been applied to investigate color of the electro-generated anionic and cationic forms of the complexes.     

Synthesis and characterization of octakis(4,5-bis{2-[2-(1-naphthyloxy)ethoxy]ethoxy})- substituted metal-free and metallophthalocyanines

The synthesis of octakis(4,5-bis{2-[2-(1-naphthyloxy)ethoxy]ethoxy}) metal-free (4) and metallophthalocyanines (5–8) were carried out by the cyclotetramerization of a 4,5-bis{2-[2-(1-naphthyloxy)ethoxy]ethoxy}phthalonitrile (3). Newly substituted octakisphthalocyanines showed enhanced solubility in organic solvents. The new compounds were characterized by IR, ¹H-NMR, ¹³C-NMR, UV-Vis, and MS spectral data.     

Electrochemistry of Novel Phthalocyanines Bearing 1,2,4 Triazole Groups

The phthalonitrile (3) and triazole substituted metallo phthalocyanines (MPc) (4–7) were prepared. The novel compounds were characterized with spectroscopic data. Electrochemical analyses of metallophthalocyanines (4–7) bearing triazole substituents were performed to investigate redox activity of phthalocyanines (Pcs) ring. While incorporation of Ni²⁺ and Cu²⁺ cations in the Pc core only influenced peak positions of Pc ring processes, Co²⁺ and Cl^1?Fe³⁺ cations of CoPc and FePc gave extra redox couples to the Pc based ones. Releasing the axial Cl^1? anion on Fe³⁺ cation of FePc during the reduction reactions complicated the redox responses. Redox reactions of Co²⁺ and Fe³⁺ metal centers also considerable influenced spectral and color responses of these complexes.     

Anionic water-soluble sulfonated phthalocyanines: microwave-assisted synthesis,aggregation behaviours,electrochemical and in-situ spectroelectrochemical characterisation

In this work, a phthalonitrile derivative bearing p-sulfonylphenoxy group at the 3-position has been synthesised. The water-soluble non-peripherally tetrasubstituted zinc (3) and cobalt (4) phthalocyanines were obtained by cyclotetramerisation of this phthalonitrile derivative in the presence of anhydrous metal salts by microwave irradiation. The compounds have been characterised by using FT-IR, ¹H NMR, UV–Vis and Mass spectrometry (MS) data. The aggregation behaviours of these compounds were investigated in methanol, DMSO, DMF, and water. We have also studied the aggregation behaviours of the phthalocyanine complex 3 in various DMSO/water mixtures. Additionally, the redox properties of the phthalocyanine complexes were examined in dimethylsulfoxide by voltammetry and in situ spectroelectrochemistry. Redox behaviours of the complexes supported the structures of the complexes. Metal and ring-based reductions were observed for 4 and only ring-based electron transfer processes were observed with 3.     

Metallo Phthalocyanines bearing 2‐Isopropyl‐6‐methylpyrimidin‐4‐yloxy Substituents: Synthesis,Characterization, Aggregation Behavior,Antioxidant and Antibacterial Activity,and Electronic Properties

A novel phthalonitrile derivative bearing 2‐isopropyl‐6‐methylpyrimidin‐4‐yloxy substituents at peripheral positions was synthesized by a nucleophilic substitution reaction. Metallophthalocyanines were obtained from the reaction of the novel phthalonitrile with metal Zn, Cu, Co, and Ni salts. The characterization of the compounds was performed using elemental analysis as well as UV/Vis, FT‐IR, and ¹H‐NMR spectroscopy. The aggregation behaviors of phthalocyanine complexes were also investigated. These metallophthalocyanines do not show any aggregation behavior between 10^–4–10^–6 M concentration range in THF. The antioxidant activities of the synthesized compounds were evaluated using three different tests: 2, 2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging, metal chelating activity, and reducing power assays. All the compounds exhibited various antioxidant activities. In addition, antimicrobial activity of the compounds was tested over four gram positive and two gram negative bacteria. Moreover, the ground‐state geometries of the complexes were optimized using density functional theory (DFT) methods at B3LYP/6‐31G(d, p) level in order to obtain information about the 3D arrangements and electronic structure.     

Cobalt complexes based on 2-(1H-benzimidazol-2-yl)-phenol derivatives: preparation,spectral studies,DFT calculations and catalytic behavior toward ethylene oligomerization

In this study, five novel Co(II) complexes of 2-(1H-benzimidazol-2-yl)-phenol derivatives (HL_x: x = 1–5) have been synthesized and characterized. The general formula for complexes C1 and C2 is K₂[Co(HL_1,2)₂Cl₂]·H₂O, for complex C3 K₂[Co(HL₃)₂Cl₂], and for complexes C4 and C5 [Co(HL_4,5)₂]. In all complexes, the ligands are coordinated as bidentate, via one imine nitrogen and the phenolate oxygen atoms. The structures of the compounds were characterized by FT-IR, UV–vis, ¹H, ¹³C NMR spectroscopies, ICP and elemental analysis (C, H, and N). The purity of these compounds was ascertained by melting point (m.p.) and TLC. Geometry optimization of the studied complexes was done by Gaussian09 software at B3LYP/TZVP level of theory and satisfactory theoretical–experimental agreement was achieved for NMR and IR spectra of the compounds. Based on the combined experimental and theoretical studies, six-coordinate octahedral structures have been proposed for complexes C1–C3, while complexes C4 and C5 had distorted tetrahedral geometry. All complexes were activated with diethylaluminum chloride (Et₂AlCl), cobalt(II) complexes containing bulky methyl groups in the aryl moiety show high catalytic activities (1774 kg?mol^?1(Co)?h^?1) for ethylene oligomerization. The oligomers obtained from the cobalt complexes exhibit good selectivity for linear 1-butene and 1-hexene. Results revealed that both the steric and electronic effects of ligands strongly affect the catalytic activities and the properties of the catalytic products.     

Synthesis, characterization and aggregation behaviour of novel peripherally tetra-substituted octacationic water soluble metal-free and metallophthalocyanines

In this study, a new phthalonitrile derivative 3 bearing 1,3-bis[3(dimethylamino)phenoxy]propan-2-ol 1, metal-free phthalocyanine (Pc) 4, metallophthalocyanines (MPcs) 5–7 and their quaternized derivatives 4a–7a were synthesized. Metal-free Pc 4 was prepared by cyclotetramerization of phthalonitrile derivate 3 and MPcs 5–7 were synthesized by heating 3 with NiCl₂, CoCl₂ and CuCl₂ in n-pentanol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, respectively. Quaternization of the dimethylamino functionality produced quaternized octacationic water soluble metal-free, Ni, Co and Cu Pcs which were soluble in water, DMF, DMSO. The aggregation behaviour of these compounds were investigated in different concentrations of chloroform for metal-free, Ni, Co and Cu Pcs. The effect of solvents on absorption spectra were studied in various organic solvents. The novel compounds were characterized using IR, ¹H-, ¹³C NMR, UV–vis and MS spectral data.     

Microwave assisted synthesis and characterization of novel metal-free and metallophthalocyanines containing four pyridyl groups

The novel tetrasubstituted metal-free phthalocyanine (4) and metallophthalocyanines (5, 6, 7 and 8) bearing four pyridyl group moieties on peripheral positions have been synthesized by cyclotetramerization of the phthalonitrile derivative (3) in a multi-step reaction sequence. The new compounds were characterized by a combination of elemental analysis, ¹H- and ¹³C-n.m.r., i.r., U.V.–vis and m.s. spectral data.     

α- or β-Substituted functional phthalocyanines bearing thiophen-3-ylmethanol substituents: synthesis,characterization, aggregation behavior and antioxidant activity

The tetra α- or β-thiophene substituted metal and metal-free phthalocyanines (Pcs) M[Pc(α-OCH₂Thiopen)₄] and M[Pc(β-OCH₂Thiopen)₄] {(α-ThMet-MPc), (β-ThMet-MPc) [ThMet: Thiophene methoxy], M = Zn(II), Co(II) and, 2H} were synthesized from the corresponding 3’-(thiophen-3-ylmethoxy)phthalonitrile or 4’-(thiophen-3-ylmethoxy)phthalonitrile (ThMePN). The structural characterization, spectral, and antioxidant properties of a series of new Pcs were also presented. Both α- and β-substituted Pc complexes increased solubility in polar solvents, such as THF, DMF, and DMSO. FT-IR, ¹H-NMR, ¹³C-NMR, UV–vis, MALDI-TOF/MS spectral, and elemental analysis data were used to characterize the compounds. The aggregation behaviors of 3–8 were also investigated at different concentrations in THF. Antioxidant test methods, α,α-diphenyl-β-picrylhydrazyl radical scavenging activity, metal chelating activity, and reducing power, were used to determine the antioxidant activities. 6 showed very good ferrous ion chelating activity of 81 ± 1%. 6, 5, 4, and 3 showed better reducing power than trolox, ascorbic, acid and butylated hydroxytoluene, commercially used antioxidants.     

Preparation and characterization of PEPPSI-palladium N-heterocyclic carbene complexes using benzimidazolium salts catalyzed Suzuki–Miyaura cross coupling reaction and their antitumor and antimicrobial activities

New palladium complexes were efficiently synthesized from the reaction of benzimidazolium salts 2a–e, potassium carbonate (K₂CO₃) and palladium chloride (PdCl₂) in pyridine (for 3a–e). The catalytic activity of these complexes in a catalytic system including palladium complexes and K₂CO₃ in DMF-H₂O was evaluated in Suzuki–Miyaura cross-coupling reactions of aryl bromides and chlorides with phenylboronic acid. Our novel complexes show excellent catalytic activities with high turnover numbers (TON) and high turnover frequencies (TOF) (e.g. for the Suzuki–Miyaura reaction: TON up to 370 and TOF up to 123.3?h^?1). Both benzimidazolium salts 2a–e and complexes 3 have been characterized using spectroscopic data and elemental analysis. The antimicrobial activity of the N-heterocyclic carbene palladium complexes 3a–e varies with the nature of the ligands. Also, the IC₅₀ values of both, complexes (3a–e) and benzimidazoles 2a–e, have been determined. In addition, the new palladium complexes were screened for their antitumor activity. Complexes 3e and 3d exhibited the highest antitumor effect with IC₅₀ values 6.85?μg/mL against MCF-7 and 10.75?μg/mL against T47D, respectively.     

Derivatizable novel β-tetra 7-oxycoumarin-3-carboxylate substituted metallophthalocyanines: Synthesis and characterization

In this study, a novel phthalonitrile, ethyl 7-(3,4-dicyanophenoxy)coumarin-3-carboxylate (1), was prepared and characterized. The metallophthalocyanines (3–6) were prepared by cyclotetramerization of 1 with the corresponding metal salts {Zn(OAc)₂·2H₂O, Co(OAc)₂·4H₂O, Cu(OAc)₂, Ni(OAc)₂·4H₂O} in 2-chloronaphthalene. Reaction of 3 with aqueous hydrochloric acid gave the coumarino-zincphthalocyanine (3a) carrying carboxyl groups at the 3-position of all the coumarin moieties. Treatment of compound 3a with aqueous NaOH_./AgNO₃ or aqueous NaOH in N,N-dimethylformamide (DMF) gave the expected silver (3c) or sodium (3d) salts, respectively. The four carboxylic groups in coumarino-zincphthalocyanine (3a) and the four carboxylate groups in 3d make the compounds have good solubility in water. Heating of the acyl chloride derivative of 3 with morpholine in DMF yielded the corresponding 3-carboxymorpholinamide (3b). The newly prepared compounds, phthalonitrile and metallophthalocyanines, have been characterized by FT-IR, UV–Vis, MALDI-TOF and ¹H NMR spectroscopies.     

Synthesis,spectral, and catalytic studies of ruthenium(II) unsymmetrical Schiff-base complexes

Unsymmetrically-substituted ruthenium(II) Schiff-base complexes, [Ru(CO)(B)(L ^x )] [B = PPh₃, AsPh₃ or Py; L ^x = dianion of tetradentate unsymmetrical Schiff-base ligand; x = 4–7, L⁴ = salen-o-hyac, L⁵ = valen-o-hyac, L⁶ = salphen-o-hyac, L⁷ = valen-2-hacn], were prepared and characterized by analytical, IR, electronic, and ¹H NMR spectral studies. The new complexes were tested for their catalytic activity towards the oxidation of benzylalcohol to benzaldehyde.     

Oxidation of Sulfides with Hydrogen Peroxide Catalyzed by Vitamin B2 Derivatives

5-Ethyl-3-methyl-2′,4′:3′,5′-di-O-methylenedioxyriboflavinium perchlorate (1, DMRFlEt⁺ClO₄ ^–), derived readily from commercially available vitamin B₂ (riboflavin), exhibits high catalytic activity for the oxidation of organic sulfides with hydrogen peroxide. The reaction provides an efficient and selective method for the oxidative transformation of organic sulfides to the corresponding sulfoxides under mild conditions.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

Organoruthenium(II) compounds with pyridyl benzoxazole/benzthiazole moiety: studies on DNA/protein binding and enzyme mimetic activities

We report herein synthesis and characterization of four new organoruthenium(II) complexes of the type [RuH(CO)(PPh₃)₂(L_1,2)]Cl (1, 3) and [Ru(CO)(Cl)₂(AsPh₃)(L_1,2)] (2, 4) derived from the reaction of [RuHCl(CO)(EPh₃)₃] (E = P or As) with 2-(pyridine-2yl)benzoxazole (L₁) and 2-(pyridine-2yl)benzthiazole (L₂). Single-crystal X-ray diffraction data of 2 proved octahedral geometry of the complexes with a 1?:?1 ratio between the metal and the coordinated ligands. The binding affinities of 1–4 toward calf-thymus DNA (CT-DNA) and BSA were thoroughly studied by various spectroscopic techniques. Furthermore, the coordination compounds exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone and phosphatase-like activities in the hydrolysis of 4-nitrophenyl phosphate to 4-nitrophenolate ion. The kinetic parameters have been determined using Michaelis–Menten approach. The highest k_cat values suggested that coordination compounds exhibit higher rates of catalytic efficacy.     

Heteroleptic palladium(II) complexes containing N-heterocyclic carbenes and 4-phenyl-1H-1,2,3-triazole: Synthesis,characterization, and catalytic application

Abstract

Reaction of the dimeric N-heterocyclic carbene (NHC) palladium compounds [Pd(μ-Cl)(Cl)(NHC)]₂ with 4-phenyl-1H-1,2,3-triazole gave four mono- and dinuclear complexes 1–4. Mononuclear complexes 1 and 2 [(NHC)PdCl₂(4-phenyl-1H-1,2,3-triazole)] were obtained when the reactions were performed in CH₂Cl₂, whereas dinuclear complexes 3 and 4 [Pd₂(μ-Cl)(μ-4-phenyl-1H-1,2,3-triazole)Cl₂(NHC)₂] were obtained when the reactions were performed in THF in reflux with Et₃N as the base. Further explorations of the catalytic properties of 1–4 for Pd-catalyzed transformations have been performed and these complexes exhibited moderate to high catalytic activities for Suzuki–Miyaura coupling and arylation of benzoxazoles with aryl bromides.     

Preparation,characterization, DFT calculations and ethylene oligomerization studies of iron(II) complexes bearing 2-(1H-benzimidazol-2-yl)-phenol derivatives

Five 2-(1H-benzimidazol-2-yl)-phenol derivatives including 1H (HL₁), 5-chloro-(HL₂), 5-methyl-(HL₃), 5,6-dichloro-(HL₄), and 5,6-dimethyl-(HL₅) were synthesized by the reaction of their corresponding benzene-1,2-diamine precursors and 2-hydroxybenzaldehyde which subsequently was employed in complexation with Fe(II) to prepare complexes C1–C5, respectively. Indeed, in all complexes, the ligands were coordinated as bidentate, via the C=N nitrogen and hydroxy oxygen atom of benzimidazole moiety and phenol ring, respectively. The compounds were characterized by FTIR, UV–vis, ¹H- and ¹³C-NMR spectropscopy, ICP, and elemental analysis (C, H, and N). The purity of these compounds was determined by melting point (m.p )and TLC. The synthesized ligands and complexes were geometrically optimized by Gaussian09 software at B3LYP/TZVP level of theory and satisfactory theoretical–experimental agreement was achieved for analysis of IR data of the compounds. Catalytic behavior of the iron(II) complexes was investigated for ethylene reactivity. On activation with diethylaluminum chloride (Et₂AlCl), iron(II) complex (C4) showed the highest activity (1686 kg oligomers.mol^?1(Fe).h^?1) for ethylene oligomerization when it contains chlorine substituents and exhibits good selectivity for linear 1-butene. The steric and electronic effects of ligands were investigated in detail on the influence of their catalytic activities.     

Synthesis,characterization and ascorbic acid oxidase mimetic catalytic activity of copper(II) picolyl hydrazone complexes

Four new picolyl hydrazones were prepared via Schiff-base condensation of picolonic acid hydrazide with α-formyl-(L¹), α-acetyl-(L²), α-benzoyl-(L³) pyridine and α-formyl-(L⁴) thiophene. Copper(II) complexes of these hydrazones and a series of copper(II) complexes containing (L²) and various anions (Cl, Br, NO₃, SCN, SO₄, ClO₄, AcO, PF₆ and BF₄) have been synthesized. Elemental, thermal analysis, molar conductivity, magnetic moment measurements and spectral (i.r., electronic and e.s.r.) studies have been used to characterize the prepared compounds. The overall structure and reactivity of the reported copper(II) chelates critically depend on the ligand structure and the nature of counter anion incorporated in the complex molecule. Octahedral [complex (7)], square-pyramidal [complex (8)] and square-planar monomeric species [complexes (1–6), (9) and (10)] and a dimeric structure with oxygen bridge in square-planar geometry [complexes (11) and (12)] were suggested. The reported copper(II) complexes exhibit promising oxidase catalytic activity towards the aerobic oxidation of vitamin C. A linear correlation exists between the oxidase catalytic activity and the Lewis-acidity of the central copper(II) ion created by the donating properties of the parent ligand, as well the irregularity of the coordination environment. The probable mechanistic implications of the catalytic oxidation reactions are discussed.