Novel peripherally tetra substituted metal-free,cobalt(II), copper(II) and manganese(III) phthalocyanines bearing polyethoxy chain attached by 2,6-diphenylphenol groups: synthesis,characterization and their electrochemical studies

Metal free (6), cobalt(II) (7), copper(II) (8) and manganese(III) (9) phthalocyanines, which are tetra substituted at the peripheral positions with 2-[2-(1,1′:3′,1′′-terphenyl-2′-yloxy)ethoxy]ethoxy groups, were synthesized and characterized by IR, ¹H-NMR,¹³C-NMR, UV–Vis and mass spectroscopy. Electrochemistry of the phthalocyanines were studied with voltammetric measurements by using cyclic voltammetry and square wave voltammetry techniques in DCM/TBAP electrolyte on a Pt working electrode. Electrochemical measurements exhibit that incorporation of redox active metal ions, Co^II and Mn^III, into the phthalocyanine core extends the redox capabilities of the Pc ring including the metal-based reduction couples of the metal. While Mn^IIIClPc showed only metal based reduction reactions, Co^IIPc showed metal based and ligand based reduction reactions as expected. Cyclic and square wave voltammetric studies showed that phthalocyanines have reversible/quasireversible/irreversible redox processes, which are the main requirement for the technological usage of these compounds.     

Synthesis,spectroscopic, electrochemical and spectroelectrochemical properties of metal free,manganese, and cobalt phthalocyanines bearing peripherally octakis-[4-(thiophen-3-yl)-phenoxy] substituents

Metal free (2), manganese (3), and cobalt (4) phthalocyanines, which are octa-substituted at the peripheral positions with [4-(thiophen-3-yl)-phenoxy] moieties, were synthesized and electrochemical properties were reported for the first time. The complexes were characterized by elemental analysis, IR, ¹H NMR, mass spectroscopy, and electronic spectroscopies. Electrochemical and spectroelectrochemical measurements exhibit that incorporation of the redox active metal ions, Co^II and Mn^IIIOAc, into the phthalocyanine core extends the redox richness of the Pc ring with the reversible metal-based reduction and oxidation couples in addition to the common Pc ring-based electron transfer processes. Presence of molecular oxygen in the electrolyte system causes to form π-oxo MnPc complexes, which alter the voltammetric and spectroelectrochemical responses of the complex. An in situ electrocolorimetric method has been applied to investigate the color of the electro-generated anionic and cationic forms of the complexes for possible electrochromatic applications.     

Synthesis and investigation of spectroelectrochemical properties of peripherally tetra-substituted phthalocyanine bearing 3-(4-{[3-(trifluoromethyl)benzyl]oxy}phenyl)propan-1-ol and its metallo compounds

In this study, the new compounds; 3-(4-{[3-(trifluoromethyl)benzyl]oxy}phenyl)propan-1-ol 3 was prepared by the reaction of 4-(3-hydroxypropyl)phenol 1 with 1-(bromomethyl)-3-(trifluoromethyl)benzene 2 and 4-[3-(4-{[3 (trifluoromethyl)benzyl]oxy}phenyl)propoxy] phthalonitrile 5 was synthesized by the reaction of 4-nitrophthalonitrile 4 with 3-(4-{[3-(trifluoromethyl)benzyl]oxy}phenyl)propan-1-ol 3. Novel peripherally tetra substituted H₂Pc 6, Co(II) 7, Cu(II) 8, Ni(II) 9 and Fe(II) 10 phthalocyanines, which have peripheral positions with 4-[3-(4-{[3 (trifluoromethyl)benzyl]oxy}phenyl)propoxy] groups, were synthesized and all of the new compounds characterized by IR, ¹H NMR, ¹³C NMR, UV–Vis, mass spectroscopies and elemental analysis. The electrochemical and spectroelectrochemical investigation of the phthalocyanines carrying 4-[3-(4-{[3 (trifluoromethyl)benzyl]oxy}phenyl)propoxy] groups were studied using various electrochemical techniques in DMF on a glassy carbon electrode. Cyclic voltammetry and square wave voltammetry studies show that the complexes have either metal based or ligand-based diffusion controlled electron transfer properties. To shed more light on the electron-transfer steps of the complexes and assignments of the redox couples were carried out by spectroelectrochemical measurements. The color changes during spectral changes of redox species were recorded with in situ electrocolorimetric measurements. The electrochemical and in situ UV–Vis spectral change of complexes indicated their applicability in the fields of the electrochemical technologies.     

Ionic complexes simultaneously containing fullerene anions and coordination structures of metal phthalocyanines with I<Superscript>−</Superscript> and EtS<Superscript>−</Superscript> anions

The ionic complexes simultaneously containing negatively charged coordination structures of metal phthalocyanines and fullerene anions, viz., {Mn^IIPc(CH₃CH₂S^?) _x ·(I^?)_1?x }·(C₆₀ ^·?)· ·(PMDAE⁺)₂·C₆H₄Cl₂ (PMDAE is N,N,N′,N′,N′-pentamethyldiaminoethane, x = 0.87, 1) and {Zn^IIPc(CH₃CH₂S^?)_y·(I^?)_1?y }₂·(C₆₀ ^?)₂·(PMDAE⁺)₄·(C₆H₄Cl₂) (y = 0.5, 2) were synthesized. The both compounds were obtained as single crystals, which made it possible to study their crystal structures. In complex 1, the fullerene radical anions form honeycomb-like layers in which each fullerene has three neighbors with center-to-center interfullerene distances of 10.13–10.29 Å. Rather long distances between the C₆₀ ^·? radical anions results in the retention of monomeric C₆₀ ^·? in this complex down to the temperature of 110(2) K. In complex 2, fullerenes form dimers (C₆₀ ^?)₂ bonded by one C-C bond. The dimers are packed in corrugated honeycomb-like layers with interfullerene center-to-center distances of 9.90–10.11 Å. Manganese(II) and zinc(II) phthalocyanines coordinate iodide and ethanethiolate anions to the central metal atom to form unusual negatively charged coordination structures M^IIPc(An^?) (An^? is anion) packed in dimers {M^IIPc(An^?)}₂ with a short distance between the phthalocyanine planes (3.14 Å in 1 and 3.27 Å in 2). The pthalocyanine dimers also form layers with the PMDAE⁺ cations, and these layers alternate with the fullerene layers. The packing of spherical fullerenes with planar phthalocyanine molecules is attained by the insertion of fullerenes between the phenylene groups of phthalocyanines. The π-π-interactions of the porphyrin macrocycle with five- or six-membered fullerene rings are characteristic of the earlier studied ionic porphyrin and fullerene complexes. Such interactions are not observed for ionic complexes 1 and 2.     

Cation-induced aggregation of sandwich lutetium(III) and Yb(III) complexes with tetra(15-crown-5)-substituted phthalocyanine as probed by <Superscript>1</Superscript>H NMR

The cation-induced aggregation of sandwich crown-substituted complexes [Ln(R₄Pc)₂] (Ln = Lu (I) and Yb (II), R₄Pc^2? is the 4,5,4′,5′,4″,5″,4?,5?-tetrakis(1,4,7,10,13-pentaoxatridecamethylene)phthalocyaninate ion) and Ln₂(R₄Pc)₃(Ln = Lu (III) and Yb (IV) in a CDCl₃-DMSO-d ₆ solution has been studied by ¹H NMR. The data obtained are consistent with the conclusions concerning the composition of supramolecular aggregates drawn from spectrophotometric titration data. The molecules of double-decker complexes I and II form supramolecular oligomers, whereas triple-decker complexes III and IV form supramolecular dimers, which is presumably due to the stronger distortion of the planes of the outer decks of the triple-decker complexes as compared to their double-decker analogues.     

Crown-substituted Sc(III) phthalocyaninates: Synthesis and spectral properties

The scandium(III) complexes with tetra(15-crown-5)phthalocyanine [Sc(R₄Pc)₂]^·0 (I) and Sc(R₄Pc) · OAc (II) have been synthesized by condensation of Sc³⁺ with phthalocyanine H₂R₄Pc (4,5,4′,5′,4″,5″,4?,5?-tetrakis(1,4,7,10,13-pentaoxatridecamethylene)phthalocyanine). Compounds I and II have been characterized by spectral methods: electronic absorption spectroscopy, MALDI-TOF MS, IR spectroscopy, and ¹H NMR. The redox properties of I and the photoluminescent properties of II have been studied.     

The synthesis and structural characterization of transition metal coordination complexes of coumarilic acid

The coumarilate (coum^?) complexes of Co^II(1), Ni^II(2) Cu^II(3) and Zn^II(4) were synthesized and characterized by elemental analysis, magnetic susceptibility, solid-state UV–Vis, FTIR spectra, thermoanalytical TG–DTG/DTA and single-crystal X-ray diffraction methods. It was found that all of the complex structures have 2 mol (coum^?) ligand bonded as monoanionic monodentate in the structures of 1 and 2 while they were coordinated to metal cations as monoanionic bidentate in the complexes 3 and 4. There was not any hydrate water in the metal complexes. The complexes of 1 and 2 have four moles of aqua ligand, and the other complexes have two moles. Thermal decomposition of each complex starts with dehydration, and then the decomposition of organic parts goes. The thermal dehydration of the complexes takes place in one (for the compounds of 2, 3, 4) or two (for the compound 1) steps. The decomposition mechanism and the thermal stability of the complexes under investigation were determined on the basis of their structures. Metal oxides were obtained as the final decomposition product.     

Synthesis and photophysical studies of monocarboxy phthalocyanines containing quaternizable groups

This work reports on the synthesis and photophysical properties of novel unsymmetrically substituted monocarboxy magnesium (MgPc, 3), aluminum (ClAlPc, 4) and unmetallated (H₂Pc, 5) phthalocyanines. Magnesium phthalocyanine (3) was converted into water soluble quaternized derivative (QMgPc, 6) by reaction with methyl iodide. The synthesized phthalocyanines were characterized by IR, UV-Vis, NMR, mass spectrometry and elemental analyses. Photophysical and photochemical studies were carried out in order to determine the potential of the complexes as photosensitizers for use in photodynamic therapy. Triplet quantum yields ranged from 0.37 to 0.40 and triplet lifetimes from 110 to 140 μs in DMSO.     

Synthesis,characterization and X-ray crystal structure of novel nickel Schiff base complexes and investigation of their catalytic activity in the electrocatalytic reduction of alkyl and aryl halides

Novel potentially bidentate NO Schiff base ligands, HL ¹ and HL ² derived from condensation reaction of 2′-methoxyphenyl-2-ethylamine with salicylaldehyde (HL ¹ ) and with 2-hydroxy-4-methoxybenzaldehyde (HL ² ), and their nickel complexes were synthesized and characterized by usual spectroscopic techniques such as FT-IR, UV–Vis, ¹H NMR, ¹³C NMR and elemental analysis. It was revealed that the bidentate Schiff base ligands coordinate with Ni(II) ions yielding mononuclear complexes with 1:2 (metal/ligand) stoichiometry. This result has been determined by using X-ray crystallographic technique of HL ² and the nickel complex derived from HL ¹ (Ni(II)-2L ¹ ). So, the structural studies showed that the two Ni(II) complexes adopt a square-planar geometry around the central metal ion. Cyclic voltammetry studies were investigated in 0.1 M TBAP in DMF solution and indicate that the nickel complexes show one reduction wave related to Ni(II)/Ni(I) redox couple. The electrocatalytical properties of these complexes were also studied in the same electrolyte medium. Their electrocatalytic performances have been tested toward the electroreduction reaction of bromocyclopentane and iodobenzene, showing a promoted activity in the case of the Ni(II)-2L ² complex.     

Synthesis and characterization of liquid crystalline tetra- and octa-substituted novel phthalocyanines

Methylene-bridged tetra- and octa-(13,17-dioxa nonacosane-15 sulfanyl)-substituted metal free- and Ni(II) phthalocyanines were synthesized from the corresponding phthalonitrile (3, 4) derivatives in the presence of the anhydrous metal salt (NiCl₂) or a strong organic base. The new compounds were characterized by elemental analyses, UV/Vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry (DSC), optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirm that tetra- and octa-substituted compounds (3a–b, 4a–b) form hexagonal columnar mesophases (Col_h). We indicated that addition of the methylene-bridged phthalocyanine (Pc) core can either decrease the liquid crystal phase transition temperatures or extend the liquid crystal temperature range to include room temperature. Also, the Pc compounds (3a, 3b, 4a and 4b) are liquid crystals at room temperature. These properties of the Pc complexes provide some advantages such as easily obtaining an ordered film for sensor applications. Computational modelling work was combined with X-ray diffraction investigation to validate the diameter of the phthalocyanine molecule (3b).     

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,characterization and extraction properties of calix[4]crown with amine units and study of its complexes with Cu(II)

In this work, we have focused on the synthesis of p-tert-butyl calix[4]crown with amine units (H ₃ L) as a class of selective receptors for metal ions. The macrocyclic ligand (H ₃ L) with N₂O₇ donors was synthesized via condensation between 1,3-diaminocalix[4]arene and 2-[3-(2-formylphenoxy)-2-hydroxypropoxy] benzaldehyde, followed by reduction of the Schiff base product in situ with sodium borohydride, then it was characterized by FT-IR, ¹H NMR and X-ray crystallography. Two Cu(II) complexes were prepared from the reaction of H ₃ L with Cu(II) salts (CuX₂, X = ClO₄ ^? and Cl^?). FT-IR, UV–Vis, elemental analysis, molar conductivity and cyclic voltammetry techniques were used for study and characterization of these complexes. On the basis of liquid–liquid extraction experiments, ligand H ₃ L indicated good affinity toward Pb²⁺ and Cu²⁺.     

Synthesis, H- or J-type aggregations,electrochemistry and in situ spectroelectrochemistry of metal ion sensing lead(II) phthalocyanines

We report, in this study, peripherally 3- and 4-substituted functionalized ionophore ligands (1–3) and their α- and β-tetra polyalcohol substituted lead(II) phthalocyanines M{Pc[S–CH(C₃H₇)(C₂H₅OH)]₄} (7, 9 and 11) and M{Pc[S–C₆H₁₂(OH)]₄} (8, 10 and 12) which are a mixture of different isomers. The complexes have been fully characterized by elemental analysis, FT-IR, ¹H NMR, ¹³C NMR, MS (MALDI-TOF) and UV–Vis spectral data. These complexes induced H-type (face-to-face fashion) or J-aggregate (edge-to-edge) dimers when titrated with AgNO₃ or Na₂PdCl₄ in a THF–MeOH solution. Cyclic and square wave voltammetry studies showed that the complexes gave three one-electron ligand-based reductions and two one-electron oxidation couples having diffusion controlled mass transfer character. Assignments of these redox couples were confirmed by spectroelectrochemical measurements. The observation of split Q bands, which are characteristic spectral behavior of metal-free phthalocyanines, indicates demetallization of the complexes during the spectroelectrochemical measurement under the applied potentials. The types of the substituents on the ring of the phthalocyanines affect the demetallization process of the complexes.     

Photophysical properties of aqueous solutions of a styryl dye in the presence of cucurbit[<Emphasis Type="Italic">n</Emphasis>]uril (<Emphasis Type="Italic">n</Emphasis> = 5, 6, 8)

Photophysical properties of aqueous solutions of the styryl dye 4-[(E)-2-(3,4-dimethoxyphenyl)-1-ethylpyridinium] perchlorate (1) in the presence of cucurbit[n]urils (CB[n]; n = 5, 6, 8) have been studied by fluorescent spectroscopy methods. The fluorescence intensity of a 10^–6 mol L^–1 solution of 1 increases by a factor of 12.6 upon the formation of 1 : 1 inclusion complexes with CB[6] or 1.3 in complexes with CB[8]. Upon the formation of inclusion complexes, the average lifetime of the electronically excited state of 1 increases to about 1 ns for both CB[6] and CB[8]. On the basis of fluorescence anisotropy measurements, the rotational relaxation times were estimated to be 408, 314, and 183 ps for the complexes with CB[6], CB[8], and for unbound 1, respectively. Using the fluorescence titration method developed for the case of poorly soluble cavitands, the binding constant of 1 with CB[6] was determined to be 1.1 × 10⁵ L mol^–1. The addition of CB[5] does not lead to changes in the photophysical properties of a solution of 1, indicating the absence of complexes between CB[5] and 1. It has been found on the basis of the experimental data that the fluorescence rate constant of 1 decreases about twice in the complex with CB[8], but doubles in the complex with CB[6].     

Directed assembly of cobalt(II) 1-H-indazole-3-carboxylic acid coordination networks by bipyridine and its derivatives: structural versatility,electrochemical properties,and antifungal activity

This paper describes the hydrothermal synthesis, full characterization, and architectural diversity of three intriguingly bioactive cobalt–organic frameworks, namely, 3D [Co(HL ^? )₂(BPY)] _n ·4nH₂O (1), 2D [Co(HL ^? )₂(BPE)] _n (2), and 2D [Co(HL ^? )₂(DPP)] _n (3) coordination polymers, synthesized through a mixed ligand strategy using H ₂ L (1-H-indazole-3-carboxylic acid) as a main structural block and the flexible bipyridine and its derivatives (BPY = 4,4′-bipydine, BPE = 1,2-bis(4-pyridyl)ethane, DPP = 1,3-bis(4-pyridyl)propane) as auxiliary ligand sources. Complexes 1–3 were isolated as air stable and slightly soluble crystalline solids and characterized using elemental analysis, FT-IR, electrochemical technique, thermogravimetric analysis, powder X-ray diffractometer, and single-crystal X-ray crystallography. The bipyridine derivatives played key roles in defining the structural space group and dimensionality feature of the obtained networks. The abundant H-bonding and π–π stacking interactions in complexes 1–3 gave rise to their intricate metal–organic structures of 3D (1), 2D (2), and 2D (3). In addition, the solutions of complexes 1–3 showed profound antifungal activities against the selected strain of Colletotrichum musae compared with the controlled group using benomyl as a traditional agrochemical fungicide.     

Lanthanide complexes with the Schiff base containing sterically hindered phenol: Synthesis,structure, and luminescence properties

The syntheses of the 2,6-di-tert-butyl-4-(2-hydroxybenzylideneamino)phenolate (L) complexes of Gd (I), Nd (II), Er (III), Yb (IV), Tm (V), Sm (VI), and Tb (VII) are described. The structures of the Gd and Er complexes are determined by X-ray diffraction analysis (CIF files CCDC nos. 1558820 (I) and 1558819 (III)). All synthesized compounds exhibit ligand-centered photoluminescence in a range of 405–485 nm. In addition, the luminescence spectra of solid samples of the neodymium and ytterbium complexes contain narrow bands of f–f transitions characteristic of Nd³⁺ and Yb³⁺ ions.     

Synthesis,structure, and fungicidal activity of mono- and binuclear mixed-ligand copper complex with <Emphasis Type="Italic">p</Emphasis>-nitrobenzoic acid and monoethanolamine

Mixed-ligand metal complexes based on ethanolamines and simple monosubstituted benzoic acids, in particular, mono- and binuclear copper complexes with monoethanolamine (MEA) and p-nitrobenzoic acid (PNBA), [Cu²⁺((PNBA)₂ ^-(MEA)₂)] (I) and [2Cu²⁺((PNBA)₄ ^-(MEA)₂(H₂O)₂)] (II), were prepared for the first time. The structures of the complexes were characterized by FT IR spectroscopy and X-ray diffraction (CIF files CCDC no. 1497849 (I) and no. 1497848 (II)). The doubly charged copper ions are coordinated at the vertices of octahedra, which are highly distorted due to the Jahn–Teller effect. In the crystals of the mononuclear complex I, the molecules are joined into columns, whereas in the binuclear compound II, a three-dimensional framework is formed owing to intermolecular H-bonds involving the nitro group. Fungicidal activities were found for compounds I, II, MEA, PNBA, previously obtained single-ligand copper complexes with MEA and PNBA, and MEA- and PNBA-based organic salt. The biological activity gradually increases in the series: ligand, single-ligand metal complex, organic salt, mono- and binuclear mixed-ligand complex, i.e., some ligands and copper ions show a synergistic effect.     

Scandium,yttrium, and ytterbium bisalkyl complexes stabilized by monoanionic amidopyridinate ligands

A reaction of Sc, Y, and Yb amidopyridinate dichlorides with the corresponding amount of LiCH₂SiMe₃ was used to synthesize bis(trimethylsilylmethyl) complexes (Ap)Ln(CH₂SiMe₃)₂-(THF) (Ap is N-mesityl-6-(2,4,6-triisopropylphenyl)pyridine-2-amide (Ap^9Me), Ln = Y (2); Ap is N-(2,6-diisopropylphenyl)-6-(2,4,6-triisopropylphenyl)pyridine-2-amide (Ap*), Ln = Sc (3), Yb (4)). An exchange reaction of yttrium amidopyridinate dichloride derivative 1 with 4 equiv. of Bu^tLi in hexane gave the corresponding di-tert-butyl derivative Ap^9MeY(Bu^t)₂(THF) (5). Molecular structures of complexes 3 and 4 were established by X-ray diffraction. A method of the ligand solid angles was used to calculate the completion degree of the metal atom coordination sphere for the series of isomorphic derivatives (Ap*)Ln(CH₂SiMe₃)₂(THF) containing the central metal ions with different ionic radii (Sc, Y, Yb, Lu). According to this method, the amidopyridinate ligand solid angle in these complexes virtually does not vary, while the solid angles of coordinated THF molecule and alkyl ligands vary within a wide range.     

New complexes of Ni(II) and Cu(II) with tridentate ONO Schiff base ligand: synthesis,crystal structures,electrochemical and theoretical investigation

In this research, we prepared a new series of the Cu(II) (1) and Ni(II) (2) metal complexes of a tridentate Schiff base ligand, (E)-2-(5-bromo-2-hydroxybenzylideneamino) phenol (H₂L). These complexes were characterized by elemental analysis, FT-IR, UV–Vis, and ¹H-NMR spectroscopy. The crystal structures of (1) and (2) were determined by X-ray diffraction studies. The single crystal X-ray diffraction analyses revealed that copper(II) cation is five-coordinated and the coordination polyhedron is a slightly distorted square pyramid. Nickel(II), on the other hand, is four-coordinated, and has a regular, square planar geometry. Further discussed were the electrochemical reduction of these complexes. We also analyzed the nature of the metal–ligand bond in the complexes through NBO and EDA analysis. Besides, vibrational sample magnetometer (VSM) revealed complex (1) was ferromagnetic.     

Synthesis and crystal structures of (2.2.2-cryptand)rubidium chloride and bromide hydrates

Two complexes, (2.2.2-cryptand)rubidium chloride and bromide hydrates [Rb(Crypt-222]Hal · 3.5H₂O (Hal = Cl (I) and Br (II)), are synthesized. The structures of isomorphic crystals of compounds I and II are studied by X-ray diffraction analysis. The crystals are trigonal: space group P \(\overline 3 \), Z = 2; I: a = 11.810 Å, c = 11.302 Å; II: a = 11.890 Å, c = 11.402 Å. The structures are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.060 (I) and 0.077 (II) for 2650 (I) and 2700 (II) independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). In crystals of complexes I and II, the [Rb(Crypt-222)]⁺ cation of the host-guest type lies on the crystallographic axis 3 and has the approximate symmetry D ₃. In complexes I and II, the coordination polyhedron of the Rb⁺ cation is a two-base-centered trigonal prism somewhat distorted to an antiprism. The crystals of compounds I and II contain H-bonded disordered cubes of the water molecules and Cl^? or Br^? anions.