Template synthesis and characterization of host (nanopores of zeolite Y)/guest (Co(II)-tetraoxodithiatetraaza macrocyclic complexes) nanocomposite materials

A series of Co(II) tetraoxodithiatetraaza macrocyclic complexes ([18]aneN₄S₂, [20]aneN₄S₂, Bzo₂[18]aneN₄S₂ and Bzo₂[20]aneN₄S₂) have been encapsulated in the nanopores of zeolite Y by template condensation reaction. Co(II) complexes with tetraoxodithiatetraaza macrocyclic ligand were entrapped in the nanopores of zeolite Y by a two-steps process in the liquid phase: (i) ion-exchange of [bis(diamine)cobalt(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); [Co(N–N)₂]²⁺–NaY; in the nano-cavity of the zeolite, and (ii) in situ template condensation of the cobalt(II) precursor complex with thiodiglycolic acid. The mode of bonding and overall geometry of the complexes and new host/guest nanocomposite materials ([Co([18]aneN₄S₂)]²⁺–NaY, [Co([20]aneN₄S₂)]²⁺–NaY, [Co(Bzo₂[18]aneN₄S₂)]²⁺–NaY, [Co(Bzo₂[20]aneN₄S₂)²⁺–NaY) has been inferred through FT-IR, DRS and UV–Vis spectroscopic techniques, BET technique, molar conductance and magnetic moment data, XRD and elemental analysis, as well as nitrogen adsorption. The average number of encapsulated Co complexes per nano-cavity was determined to be 0.33 for the Co complexes–NaY. An octahedral geometry around the cobalt(II) ion is suggested for the complexes and new host/guest nanocomposite materials.     

Synthesis,characterization, and catalytic oxidation of ethylbenzene over host (zeolite-Y)/guest (copper(II) complexes of tetraaza macrocyclic ligands) nanocomposite materials

Cu(II) complexes of 14- and 16-membered tetraaza macrocyclic ligands have been encapsulated in nanopores of zeolite-Y by a two-step process in the liquid phase: (1) adsorption of [bis(diamine)copper(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, and 1,3-diaminobenzene); [Cu(N–N)₂]²⁺–NaY; in the nanopores of the zeolite-Y and (2) in situ condensation of the copper(II) precursor complex with ethylcinnamate. The new host–guest nanocomposite materials were characterized by chemical analysis and spectroscopic methods. The “neat” and encapsulated complexes exhibit good catalytic activity in the oxidation of ethylbenzene at 333 K, using tert-butyl hydroperoxide as the oxidant. Acetophenone was the major product though small amounts of o- and p-hydroxyacetophenones were also formed revealing that C–H bond activation takes place both at benzylic and aromatic ring carbon atoms.     

Synthesis, characterization and catalytic oxidation of cyclohexene with molecular oxygen with host (nanopores of zeolite-Y)/guest (Ni(II) complexes of 14- and 16-membered tetraaza dioxo diphenyl macrocyclic ligands) nanocomposite materials

Ni(II) complexes of [14]aneN₄: 1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane; [16]aneN₄: 1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane; Bzo₂[14]aneN₄: dibenzo-1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane and Bzo₂[16]aneN₄: dibenzo-1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane have been encapsulated in the nanopores of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)nickel(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); [Ni(N–N)₂]²⁺–NaY; in the nanopores of the zeolite-Y, and (ii) in situ condensation of the nickel(II) precursor complex with ethylcinnamate. The new host–guest nanocomposite materials (HGNM) were characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV/Vis, XRD and DRS) and the BET technique. These complexes were used for oxidation of cyclohexene with molecular oxygen.     

Synthesis, characterization of cobalt(II) complex nanoparticles encapsulated within nanoreactors of zeolite-Y and their catalytic activities

Cobalt(II) complex nanoparticles of [14]aneN₄: 1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane; [16]aneN₄: 1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane; Bzo₂[14]aneN₄: dibenzo-1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane and Bzo₂[16]aneN₄: dibenzo-1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane have been encapsulated in the nanopores of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)cobalt(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); [Co(N–N)₂]²⁺–NaY; in the nanopores of the zeolite-Y, and (ii) in situ condensation of the cobalt(II) precursor complex with ethylcinnamate. The new complex nanoparticles entrapped in the nanoreactor of zeolite-Y were characterized by several techniques: BET, chemical analysis and spectroscopic methods (FT-IR, UV–vis, XRD, and DRS). These complexes (neat and encapsulated) were used for epoxidation of styrene with O₂ as oxidant in different solvents. Electronic spectra of the reaction mixture indicated that the oxidation proceeds through a free radical mechanism.     

Template synthesis and characterization of diaza dioxa macrocyclic nanosized cobalt(II) complex dispersed within nanocavity of zeolite-Y

Nanocavity microreactor containing 15- and 16-membered diaza dioxa Schiff-base cobalt(II) complexes “[Co(Et[15]N₂O₂)]²⁺, [Co(Pr[16]N₂O₂)]²⁺, [Co(Ph[15]N₂O₂)]²⁺ and [Co(Ch[15]N₂O₂)]²⁺” have been prepared by the template synthesis of diamine (1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene or 1,2-diaminocyclohexane) with [(1,3-bis(2-carboxyaldehydephenoxy)propane)cobalt]²⁺;[Co(BCAPP)]²⁺@NaY within the pores of zeolite-Y. The nanosized cobalt(II) complex were entrapped in the supercage of Y-zeolite by a three-step process in the liquid phase: (i) exchange of Co(II) ions with NaY in water solution, (ii) reaction of Co(II)–NaY with excess BCAPP in methanol; [Co(BCAPP)]²⁺@NaY; (iii) template synthesis of [Co(BCAPP)]²⁺@NaY with diamine. The new nanosized complex entrapped in the nanocavity of zeolite Y was characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV–Vis, XRD, BET, DRS, XPS, TGA).     

Synthesis,characterization and catalytic oxidation of cyclohexene with molecular oxygen over host (nanopores of zeolite-Y)/guest ([Ni([R]2-N2X2)]2+ (R = H,CH3; X = NH,O, S) nanocatalyst

Nickel(II) complexes of 12-membered macrocyclic ligands with different donating atoms (N₂O₂, N₂S₂ and N₄) in the macrocyclic ring have been encapsulated in the nanocavity of zeolite-Y by the fexible-ligand method. Nickel(II) complexes with macrocyclic ligands were entrapped in the nanocavity of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of precursor ligand; 1,2-di(o-aminophenyl-, amino, oxo, thio)ethane, N₂X₂; in the supercages of the Ni(II)–NaY, and (ii) in situ condensation of the Ni(II) precursor complex; [Ni(N₂X₂)]²⁺; with glyoxal or biacetyl. The new host–guest nanocatalysts (HGNM), [Ni([R]₂-N₂X₂)]²⁺–NaY (R = H, CH₃; X = NH, O, S), have been characterized by FT-IR, DRS and UV–Vis spectroscopic techniques, XRD and elemental analysis, as well as nitrogen adsorption, and were used for oxidation of cyclohexene with molecular oxygen.     

Host (nanopores of zeolite-Y)/guest (Ni(II)-tetraoxo dithia tetraaza macrocyclic complexes) nanocomposite materials: template synthesis and characterization

Nickel(II) complexes with six co-ordinate tetraoxo dithia tetraaza macrocyclic ligands derived from diamine and which provide a N₄S₂ co-ordination sphere, [18]aneN₄S₂: 1,4,10,13-tetraaza-5,9,14,18-tetraoxo-7,16-dithia-cyclooctadecane, [20]aneN₄S₂: 1,5,11,15-tetraaza-6,10,16,20-tetraoxo-8,18-dithia-cyclocosane, Bzo₂[18]aneN₄S₂: dibenzo-1,4,10,13-tetraaza-5,9,14,18-tetraoxo-7,16-dithia-cyclooctadecane, Bzo₂[20]aneN₄S₂: dibenzo-1,5,11,15-tetraaza-6,10,16,20-tetraoxo-8,18-dithia-cyclocosane, were entrapped in the nanopores of zeolite NaY by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)nickel(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); [Ni(N–N)₂]²⁺-NaY; in the nanopores of the zeolite, and (ii) in situ template condensation of the nickel(II) precursor complex with thiodiglycolic acid. The mode of bonding and overall geometry of the complexes and new host/guest nanocomposite materials ([Ni([18]aneN₄S₂)]²⁺-NaY, [Ni([20]aneN₄S₂)]²⁺-NaY, [Ni(Bzo₂[18]aneN₄S₂)]²⁺-NaY, [Ni(Bzo₂[20]aneN₄S₂)²⁺-NaY) has been inferred through FT-IR, DRS and UV–vis spectroscopic techniques, molar conductance and magnetic moment data, XRD and elemental analysis, as well as nitrogen adsorption. An octahedral geometry around the nickel(II) ion is suggested for the complexes and new host/guest nanocomposite materials.     

Epoxidation of cyclooctene by host (nanocavity of zeolite-Y) guest (copper(II) complexes with 16- and 17-membered diaza dioxa macrocyclic Schiff bases) nanocomposite materials

This work reports the synthesis and characterization of macrocyclic copper(II) complexes encapsulated within the nanopores of zeolite-Y. The obtained nanoparticles entrapped in the nanopores of zeolite have been characterized by FT-IR, UV–Vis, Diffuse reflectance spectra, spectroscopic techniques, molar conductance, magnetic moment data, XRD, thermal, and elemental analysis. The complexes (neat and encapsulated) were used for the oxidation of cyclooctene with tert-butyl hydroperoxide as oxidant in different solvents. The supported Cu[L₁]²⁺-Y exhibited a moderate 81.9% selectivity for epoxidation with 84.2% conversion. The catalytic activity and selectivity of the heterogeneous catalysts do not change after recycling five times.     

Host (nanocavity of zeolite-Y)/guest (12- and 14-membered azamacrocyclic Ni(II) complexes) nanocatalyst: synthesis, characterization and catalytic oxidation of cyclohexene with molecular oxygen

Ni(II) complexes of [12]aneN₄: 1,4,7,10-tetraazacyclododecane-2,3,8,9-tetraone; [14]aneN₄: 1,4,8,11-tetraazacyclotetradecane-2,3,9,10-tetraone; Bzo₂[12]aneN₄: dibenzo-1,4,7,10-tetraazacyclododecane-2,3,8,9-tetraone and Bzo₂[14]aneN₄: dibenzo-1,4,8,11-tetraazacyclotetradecane-2,3,9,10-tetraone have been encapsulated in the nanopores of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)nickel(II)]; [Ni(N–N)₂]–NaY; in the supercages of the zeolite, and (ii) in situ condensation of the nickel(II) precursor complex with diethyloxalate. The new host-guest nanocatalyst (HGN) were characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV/Vis, XRD, BET, DRS) and then were used for oxidation of cyclohexene with molecular oxygen.     

Synthesis and characterization of 18- and 20-membered hexaaza macrocycles containing pyridine manganese(II) complex nanoparticles dispersed within nanoreactors of zeolite-Y

Manganese(II) complexes of [18]py₂N₄: 3,6,14,17,23,24-hexaazatricyclo[17.3.1.1^8,12]tetracosa-1(23),2,6,8(24),9,11,13,17,19,21-decane; [20]py₂N₄: 3,7,15,19,25,26-hexaazatricyclo[19.3.1.1^9,13]hexacosa-1(25),2,7,9(26),10,12,14,19,21,23-decaene; Bzo₂[18]py₂N₄: 3,10,18,25,31,32-hexaazapentacyclo[25.3.1.1.^12,16.0^4,9.0^19,24]dotriaconta 1(31),2,4(9),5,7,10,12(32),13,15,17,19,21,23,25,29-hexadecane and Bzo₂[18]py₂N₄: 2,10,16,24,30,32-hexaazapentacyclo[23.3.1.1^4,8.1^1,1,151^18,22otriaconta-1(29),2,4,6,8(32),9,11,13,15(31),16,18(30),19,21,23,25,27-hexadecane have been encapsulated in the nanopores of zeolite-Y by the template condensation reaction. Mn(II) complexes with macrocyclic ligand were entrapped in the nanocavity of zeolite-Y by a two-step process in the liquid phase: (i) the adsorption of [bis(diamine)manganese(II)]; [Mn(diamine)₂]²⁺@NaY; in the supercages of the zeolite, and (ii) in situ condensation of the manganese(II) precursor complex with 2,6-diacetylpyridine. The new complex nanoparticles entrapped in the nanoreactor of zeolite-Y have been characterized by FT-IR, diffuse reflectance (DRS), X-ray photoelectron (XPS), thermal analysis, UV–Vis spectroscopic techniques, X-ray diffraction (XRD) and elemental analysis as well as by nitrogen adsorption.     

A contribution to 1-azapentadienylmetal chemistry: Si, Sn(II), Fe(II) and Co(II) complexes

Complexes of three related 1-azapentadienyl ligands [N(SiMe₂R¹)C(Bu^t)(CH)₃SiMe₂R]⁻, abbreviated as L (R = Bu^t, R¹ = Me), L′ (R = Me = R¹), and L″ (R = Bu^t = R¹), are described. The crystalline compounds Sn(L)₂ (1), Sn(L′)₂ (2), [Sn(L′)(μ-Cl)]₂ (3) and [Sn(L″)(μ-Cl)]₂ (4) were prepared from SnCl₂ and 2 K(L), 2 K(L′), K(L′) and K(L″), respectively, in thf. Treatment of the appropriate lithium 1-azapentadienyl with Si(Cl)Me₃ yielded the yellow crystalline Me₃Si(L) (5) and the volatile liquid Me₃Si(L′) (6) and Me₃Si(L″) (7), each being an N,N,C-trisilyldieneamine. The red, crystalline Fe(L)₂ (8) and Co(L′)₂ (9) were obtained from thf solutions of FeCl₂ with 2 Li(L)(tmeda) and CoCl₂ with 2 K(L′), respectively. Each of 1-9 gave satisfactory C, H, N analyses; 6 and 7 (GC-MS) and 1, 2, 8 and 9 (MS) showed molecular cations and appropriate fragments (also 3 and 4). The ¹H, ¹³C and ¹¹⁹Sn NMR (1-4) and IR spectra support the assignment of 1-4 as containing Sn-N(SiMe₂R¹)-C(Bu^t)(CH)₃SiMe₂R moieties and 5-7 as N(SiMe₃)(SiMe₂R¹)C(Bu^t)(CH)₃SiMe₂R molecules; for 1-4 this is confirmed by their X-ray structures. The magnetic moments for 8 (5.56 μ_B) and 9 (2.75 μ_B) are remarkably close to the appropriate Fe and Co complex [M{η³-N(SiMe₃)C(Bu^t)C(H)SiMe₃}₂]; hence it is proposed that 8 and 9 have similar metal-centred, centrosymmetric, distorted octahedral structures.     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

Studies on mononuclear chelates derived from substituted Schiff-base ligands (part 6): synthesis and characterization of a new 3-ethoxysalicyliden- p -aminoacetophenoneoxime and its complexes with cobalt(II), nickel(II), copper(II) and zinc(II)

Schiff-base complexes of cobalt(II), nickel(II), copper(II) and, zinc(II) with 3-ethoxysalicyliden-p-aminoacetophenoneoxime (HL) were prepared and characterized on the basis of elemental analyses, IR, ¹H- and ¹³C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses (TGA). A tetrahedral geometry has been assigned to the complexes.     

Polarized spectroscopy of hybrid materials of chiral Schiff base cobalt(II), nickel(II), copper(II), and zinc(II) complexes and photochromic azobenzenes in PMMA films

A chiral Schiff base complex, bis(N-R-1-phenylethyl-3,5-dichlorosalicydenaminato) cobalt(II) was prepared newly and characterized to be a distorted tetrahedral trans-[CoN₂O₂] coordination geometry. Organic/inorganic hybrid materials containing the related cobalt(II), nickel(II), copper(II), and zinc(II) complexes and photochromic azobenzene in polymethylmethacrylate (PMMA) cast films were assembled for comparison of their flexibility and molecular arrangement in the photofunctional medium. Characterization of each component and hybrid materials was carried out by means of absorption and CD spectra and thermal analysis (TG–DTA and DSC). Moreover, we have attempted to observe changes of conformation and/or molecular arrangement of the complexes or azobenzene induced by cis–trans photoisomerization of azobenzene after alternate irradiation of polarized UV and visible light. Gradual increase of optical anisotropy was observed for all the hybrid materials regardless of flexibility of Schiff base complexes, and the degree of dichroism and weak intermolecular interactions were discussed based on polarized absorption electronic spectra.     

Synthesis of new Cu(II), Ni(II) and Co(II) complexes with a bis-amide ligand functionalized with pyridine moieties: Spectral, magnetic and electrochemical studies

Three new copper(II), nickel(II) and cobalt (II) dinuclear complexes with a bis-amide ligand derived from tartaric acid have been prepared and characterized. For this purpose, the ligand (R,R)-(+)-di-N,N′-methylpyridino-tartramide (dmpt) was synthesized via the classical aminolysis of (R,R)-(+)-dimethyltartrate with pyridylmethylamine. The molecular structures of the complexes Na[Cu₂(dmptH₋₃)(CO₃)] · 8H₂O (1) and [Ni₂(dmptH₋₂)₂] · 9.75H₂O (2) were elucidated by X-ray diffraction, and the complex [Co₂(dmptH₋₃)(μ-OH)] · NaClO₄ · 5H₂O (3) by XAS. The crystal structure of (1) shows that the two metallic centres are in a square planar environment. Each copper(II) is bound to pyridyl and deprotonated amidic nitrogen atoms and to the oxygen atoms of hydroxyl and carbonato groups. In complex (2), both nickel atoms are in a distorted octahedral environment with an identical set of donors atoms, N₄O₂, coming from four nitrogen atoms of two pyridylmethylamido moieties and two oxygen donor atoms of alcohol groups. XAS analysis of complex (3) allows us to propose a CoN₂O₄ chromophore, with two nitrogen atoms coming from pyridyl and amidic groups and two bridged oxygen atoms from a deprotonated alcohol group and an hydroxyl group; the hexacoordination is achieved by two water molecules. The spectroscopic, electrochemical and magnetic properties of these complexes were investigated.     

Spectrophotometric study of coproporphyrin-I complexes of copper(II) and cobalt(II)

The reagent 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) was used for the spectrophotometric determination of copper(II) and cobalt(II) in the presence of pyridine and imidazole catalysts. Optimum conditions were investigated and the methods were applied to the determination of parts per billion levels of copper(II) and cobalt(II). The Sandell sensitivities of the recommended procedures were 0.568 μm cm⁻² and 0.464 μg cm⁻² (for A = 0.001) for copper and cobalt, respectively. The relative standard deviations were 2.0% for copper and 1.0% for cobalt. The kinetics of the reaction of CPI with copper(II) and cobalt(II) in the presence of the catalysts and the influence of the temperature were studied, and their kinetic constants determined.The influence of light on the photodecomposition of CPI was also studied.     

Synthesis and crystal structure characterization of iron(II), cobalt(II) and nickel(II) complexes with 1,3-bis(2-pyridylmethylthio)propane

Three new mononuclear complexes of nitrogen–sulfur donor sets, formulated as [Fe^II(L)Cl₂] (1), [Co^II(L)Cl₂] (2) and [Ni^II(L)Cl₂] (3) where L = 1,3-bis(2-pyridylmethylthio)propane, were synthesized and isolated in their pure form. All the complexes were characterized by physicochemical and spectroscopic methods. The solid state structures of complexes 1 and 3 have been established by single crystal X-ray crystallography. The structural analysis evidences isomorphous crystals with the metal ion in a distorted octahedral geometry that comprises NSSN ligand donors with trans located pyridine rings and chlorides in cis positions. In dimethylformamide solution, the complexes were found to exhibit Fe^II/Fe^III, Co^II/Co^III and Ni^II/Ni^III quasi-reversible redox couples in cyclic voltammograms with E_1/2 values (versus Ag/AgCl at 298 K) of +0.295, +0.795 and +0.745 V for 1, 2 and 3, respectively.     

Heptacopper(II) and dicopper(II)-adenine complexes: synthesis,structural characterization,and magnetic properties

The syntheses, crystal structures, and magnetic properties of two new copper(II) complexes with molecular formulas [Cu₇(μ₂-OH₂)₆(μ₃-O)₆(adenine)₆](NO₃)₂·6H₂O (1) and [Cu₂(μ₂-H₂O)₂(adenine)₂(H₂O)₄](NO₃)₄·2H₂O (2) are reported. The heptanuclear compound is composed of a central octahedral CuO₆ core sharing edges with six adjacent copper octahedra. In 2, the copper octahedra shares one equatorial edge. In both compounds, these basic copper cluster units are further linked by water bridges and bridging adenine ligands through N3 and N9 donors. All copper(II) centers exhibit Jahn–Teller distorted octahedral coordination characteristic of a d⁹ center. The study of the magnetic properties of the heptacopper complex revealed a dominant ferromagnetic intra-cluster interaction, while the dicopper complex exhibits antiferromagnetic intra-dimer interactions with weakly ferromagnetic inter-dimer interaction.