Search

The study was conducted to investigate the effects of nano-zirconia on the compressive and flexural strengths of concrete. For this purpose, the hydrothermal method was applied for the preparation of nano zirconia. Crystallinity, purity and structural properties of the prepared product were determined via X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR) analysis. Zirconia nanoparticles were applied as nano-filler with partial replacement of ordinary Portland cement (OPC) by 0.5, 1.0, 1.5, 2.0, 3.0 and 4.0 weight percent. The strength of OPC was determined via flexural and compressive strength tests on 3, 7 and 28 days. The results cleared that 1.5%wt have the highest improvement on the concrete. Overall, flexural and compressive strengths of OPC paste were increased first (0.5, 1 and 1.5%) then decreased (2, 3 and 4%) in 3, 7 and 28 curing days. Flexural strength was improved with 19.9% after 3 days, 17% after 7 days and 14.6% after 28 days. Compressive strength was improved with 14.9, 9.8 and 11.4% after 3, 7 and 28 days respectively.

Nanocrystalline PbS with different morphologies and particle sizes was obtained via a simple hydrothermal reaction between Pb(NO3)2 and thioglycolic acid (TGA) at relatively low temperature. Products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, photoluminescence (PL) and Fourier transform infrared (FT-IR) spectroscopy. Depending on the reactant concentration and molar ratio of TGA to the lead nitrate, the morphologies of the PbS crystals varied and the crystals with shapes of nanoparticles, star-like dendrite and nanorods were obtained. The effect of reaction temperature and reaction time on the morphology and particle sizes of nanocrystalline PbS products has been investigated.

Hierarchical pure α-nickel hydroxide (α-Ni(OH)2) nanostructures have been successfully synthesized through a one-step hydrothermal synthesis with nickel nitrate hexahydrate, ethylene-1,2-diamine (en) and hydrazine (N2H4) as morphology-directing agents. Optimum conditions to obtain high yield and phase pure α-Ni(OH)2 were identified by varying experimental parameters, such as the en and N2H4 concentration, and the reaction temperature. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. For determination of the structural formula of such α-nickel hydroxides, Fourier transform infrared (FT-IR) spectra and thermogravimetric analysis (TGA) were carried out on the as-prepared products. These results indicated that the α-nickel hydroxide contains water molecules and anions. The hierarchical NiO nanostructures are obtained on annealing the α-Ni(OH)2 nanostructures at 300 °C for 4 h. The magnetic properties of the as-prepared NiO nanostructures show a superparamagnetic behavior for the as-synthesized NiO nanostructures.

Nickel selenide (NiSe) nanoparticles were prepared from the reaction of a SeCl4 aqueous solution with a NiCl2·6H2O aqueous solution in the presence of polyvinyl alcohol (PVA) as a capping agent and hydrazine hydrate (N2H4·H2O) as a reductant through a hydrothermal method. The size, morphology, chemical composition and purity of these nanoparticles depend on the capping agent, reductant, reaction temperature and time.

Co 3 S 4 nanocrystals were synthesized via a hydrothermal technique by adding thioglycolic acid and Co(CH 3 COO) 2 ·4H 2 O as the precursors. The effect of some parameters, such as the reaction time and temperature and concentration of reactants, on the growth and morphology of the nano-structures has been studied. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy and Fourier transform infrared (FT-IR) spectra.

Star-shaped PbS nanocrystals were synthesized via a simple hydrothermal reaction between Pb(NO3)2·4H2O and thioglycolic acid at a relatively low temperature. The PbS nanostructures were then combined in a acrylonitrile–butadiene–styrene copolymer. The effect of the PbS nanostructures on the thermal stability of the nanocomposite products has been investigated. The nanostructures and nanocomposite were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectra, thermogravimetric-differential thermal analysis and atomic force microscopy. Cone calorimeter measurements showed that the heat release rate significantly decreased in the presence of PbS.

HgSe nanorods have been synthesized through a simple hydrothermal reduction approach. The nanorods formed were ≈45 nm average diameter and ≈3 μm nm in length. X-ray diffraction characterization suggested that the product consists of cubic phase pure HgSe. The as-prepared products were also characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An X-ray energy dispersive spectroscopy (EDX) study further confirmed the composition and purity of the product. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. The results showed that the capping agent CTAB (cetyltrimethylammoniumbromide) plays a crucial role in the process. Other factors, such as the reaction time, temperature, different capping agent and the reductant type also have an influence on the morphology of the final products to some extent.

Pure tin dioxide (SnO2) nanoparticles were synthesized via thermolysis of tin phthalate and tin oxalate in the presence of oleic acid (OA) as solvent. Oleic acid (OA) was employed as an organic solvent, which can be applied to control particle growth and to stabilize the particles. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. The orthorhombic phase SnO2 nanoparticles with average size about 12 nm were synthesized through thermolysis of tin phthalate in the presence of oleic acid.

Nanocavity microreactor containing 15- and 16-membered diaza dioxa Schiff-base cobalt(II) complexes “[Co(Et[15]N 2 O 2 )] 2+ , [Co(Pr[16]N 2 O 2 )] 2+ , [Co(Ph[15]N 2 O 2 )] 2+ and [Co(Ch[15]N 2 O 2 )] 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).

The synthesis of manganese oxide (Mn3O4) nanoparticles by using thermal decomposition and its physicochemical characterization are being reported in present investigation. As a new precursor, [bis(2-hydroxy-1-naphthaldehydato)manganese(II)] complex was used in the presence of oleylamine (C18H37N) as both surfactant and solvent to control the size of resulting nanoparticle. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Raman spectrum. Synthesized manganese oxide nanoparticles have a tetragonal structure with average size of 9–24 nm. The phase pure samples were characterized by using X-ray photoelectron spectroscopy (XPS) for Mn 2p level. The values of binding energies are consistent with the relative values are reported in the literature. As a comparison between two methods, the novel precursor thermally was treated in solid state reaction in different temperature, 400, 500, and 600 °C and the products were characterized by SEM images. Magnetic property of the as-prepared Mn3O4 nanoparticle shows a ferromagnetic behavior with high saturation magnetization and coercivity.

Nano-sized Cu 6 Sn 5 alloy powders were prepared by a co-precipitation reductive route using a hydrothermal method at 80 °C. The nano-size and morphology of the synthesized Cu 6 Sn 5 alloy powders were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained morphologies, chemical compositions are comparatively discussed. A variety of synthesis parameters, such as time, capping agent and sort of reductant, has an effect on the morphology of the obtained materials, and will be particularly highlighted.

The present investigation reports, the novel synthesis of nanocrystals CdS using thermal decomposition of [bis(salicylaldehydato)cadmium(II)], as a new precursor, and elemental sulfur in oleylamine. The as-synthesized CdS crystals have diameters about 10 nm. The products were characterized by X-ray diffraction (XRD) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) spectroscopy and Fourier transformed infrared (FT-IR) spectra. The results of this paper show that the shape and size of cadmium sulfide nanocrystals can be controlled systematically by adjusting certain reaction parameters, such as the reactant concentration, the reaction temperature and the reaction time. Cadmium sulfide nanoparticles and nanorods with different lengths have been successfully prepared.

Zirconia (ZrO2) nanoparticles have been synthesized through the thermolysis of bis-aqua, tris-2-hydroxyacetophenato zirconium (IV) nitrate, [Zr(HAP)3(H2O)2](NO3), as a precursor in oleylamine (C18H37N) and triphenylphosphine (C18H15P). The combination of C18H37N and C18H15P was added to act as surfactants to control the particle size. C18H37N and C18H15P play an important role in preventing aggregation of ZrO2 nanoparticles. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and Fourier transform infrared (FT-IR) spectroscopy to depict the phase and morphology. The synthesized ZrO2 nanoparticles have a cubic structure. The FT-IR spectrum showed the purity of obtained cubic phase ZrO2 nanocrystals.

Manganese(II) complexes of [18]py 2 N 4 : 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]py 2 N 4 : 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; Bzo 2 [18]py 2 N 4 : 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 Bzo 2 [18]py 2 N 4 : 2,10,16,24,30,32-hexaazapentacyclo[23.3.1.1 4,8 .1 1,1,15 1 18,22 otriaconta-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.

The present study reports the preparation and characterization of PbO nanocrystals obtained via a thermal decomposition route. The PbO nanocrystals were synthesized using lead oxalate powder as a precursor. Nanostructured products were investigated by means of XRD, TEM, FT-IR and XPS. The XRD results indicate that tetragonal phase β-PbO with a particle size of about 30–45 nm was obtained when the intermediate precipitate was calcined at 500 °C.

Nanocrystalline nickel ferrite (NiFe2O4) powder was prepared by a co-precipitation method from Ni and Fe chlorides. The as-prepared samples were characterized by powder X-ray diffractometry (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). SEM and TEM indicated that the particles were spherical with particle sizes in the range 25 ± 5 nm. The magnetic properties of the sample were measured by using a vibrating sample magnetometer, which showed that the sample exhibited typical ferromagnetic behavior at room temperature, while a finite coercivity of 245.5 Oe was present at 300 K. The saturation magnetization of the sample (23.13 emu/g) was significantly lower than that for the reported multidomain bulk particles (55 emu/g), reflecting the ultrafine nature of the sample.

Thermal decomposition process has been developed to synthesize nickel oxide (NiO) nanoclusters via the reaction between a new precursor, nickel oxalate [Ni(O4C2)(H2O)4] and oleylamine (C18H37N). The combination of triphenylphosphine (C18H15P) and C18H37N were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and ultraviolet–visible (UV–Vis) spectroscopy. The synthesized NiO nanoclusters have a cubic structure with average size 2–10 nm.

The present investigation reports the novel synthesis of copper nanocrystals using thermal reduction, and their physicochemical characterization. The copper nanocrystal powder has been prepared using [bis(2-hydroxyacetophenato)copper(II)] as a precursor. The effect of oleylamine and triphenylphosphine on the particle morphology has been investigated. Transmission electron microscopy (TEM) analysis has demonstrated that the copper nanocrystals have an average diameter of about 3 nm. The as-prepared copper nanocrystals were characterized by XRD, SEM, TEM, EDX, UV–Vis and FTIR.

The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, an hydroxyl functionalized manganese(II) Schiff-base has been covalently anchored on modified MWNTs. The new modified MWNTs have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), thermal analysis, UV–Vis, diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The results suggest that the symmetrical Schiff-base; N,N-bis(4-hydroxysalicylidene)-ethylene-1,2-diamine; H2[(OH)2-salen]; is a bivalent anion with tetradentate N2O2 donors derived from the phenolic oxygens and azomethine nitrogens. The formulae was found to be [Mn((OH)2-salen)] for the 1:1 non-electrolytic complex. The multi-wall carbon nanotubes covalently anchored manganese(II) complex ([Mn((OH)2-salen)]@MWNTs) catalyze the oxidation of cyclohexene with TBHP. Oxidation of cyclohexene catalyzed by this complex gave 2-cyclohexene-1-ol, 2-cyclohexene-1-one and 1-(tert-butylperoxy)-2-cyclohexene as the major products. The manganese(II) complex covalently anchored on MWNTs shows significantly higher catalytic activity than [Mn((OH)2-salen)]. The activity of the immobilized catalyst remains nearly the same after three cycles, suggesting the true heterogeneous nature of the catalyst. This catalyst is more selective towards 2-cyclohexene-1-one.

The present investigation reports on the novel synthesis of Mn 3 O 4 nanoparticles using thermal decomposition and their physicochemical characterization. The Mn 3 O 4 nanoparticle powder has been prepared using [bis(salicylidiminato)manganese(II)] as a precursor. The effect of oleyl amine and triphenylphosphine on the particle morphology has been investigated. Transmission electron microscopy (TEM) analysis demonstrated Mn 3 O 4 nanoparticles with an average diameter of about 25 nm. The structural study by X-ray diffraction (XRD) indicates that these nanoparticles have a pure tetragonal phase. The phase pure samples were characterized using X-ray photoelectron spectroscopy (XPS) for both Mn 2p and Mn 3s levels. The values of binding energies are consistent with related values reported in the literature.

Copper oxalate was used as a precursor to prepare metallic copper nanoparticles by thermal decomposition. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and UV–Vis spectroscopy. XRD analysis revealed broad pattern for fcc crystal structure of copper metal. The particle size by use of Debye–Scherrer’s equation was calculated to be about 40 nm.

A series of Co(II) tetraoxodithiatetraaza macrocyclic complexes ([18]aneN 4 S 2 , [20]aneN 4 S 2 , Bzo 2 [18]aneN 4 S 2 and Bzo 2 [20]aneN 4 S 2 ) 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]aneN 4 S 2 )] 2+ –NaY, [Co([20]aneN 4 S 2 )] 2+ –NaY, [Co(Bzo 2 [18]aneN 4 S 2 )] 2+ –NaY, [Co(Bzo 2 [20]aneN 4 S 2 ) 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.

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.

New square-planar Ni(II) complexes of 14-membered hexaaza macrocyclic ligands {dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane, [Ni(Bzo 2 [14]aneN 6 )](ClO 4 ) 2 ( 1 ); 3,10-dimethyl-, [Ni(Me 2 Bzo 2 [14]aneN 6 )](ClO 4 ) 2 ( 2 ); 3,10-diethyl-, [Ni(Et 2 Bzo 2 [14]aneN 6 )](ClO 4 ) 2 ( 3 ); 3,10-dibutyl-, [Ni(Bu 2 Bzo 2 [14]aneN 6 )](ClO 4 ) 2 ( 4 ); 3,10-dibenzyl-, dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane [Ni((benzyl) 2 Bzo 2 [14]aneN 6 )](ClO 4 ) 2 ( 5 ); [Ni(Bzo 2 [14]aneN 6 )](PF 6 ) 2 ( 6 ); [Ni(Me 2 Bzo 2 [14]aneN 6 )](PF 6 ) 2 ( 7 ); [Ni(Et 2 Bzo 2 [14]aneN 6 )](PF 6 ) 2 ( 8 ); [Ni(Bu 2 Bzo 2 [14]aneN 6 )](PF 6 ) 2 ( 9 ); [Ni((benzyl) 2 Bzo 2 [14]aneN 6 )](PF 6 ) 2 ( 10 ); [Ni(Bzo 2 [14]aneN 6 )Cl 2 ] ( 11 ); [Ni(Me 2 Bzo 2 [14]aneN 6 )Cl 2 ] ( 12 ); [Ni(Et 2 Bzo 2 [14]aneN 6 )Cl 2 ] ( 13 ); [Ni(Bu 2 Bzo 2 [14]aneN 6 )Cl 2 ]( 14 ); [Ni((benzyl) 2 Bzo 2 [14]aneN 6 )Cl 2 ] ( 15 ); [Ni(Bzo 2 [14]aneN 6 )(NCS) 2 ] ( 16 ); [Ni(Me 2 Bzo 2 [14]aneN 6 )(NCS) 2 ] ( 17 ); [Ni(Et 2 Bzo 2 [14]aneN 6 )(NCS) 2 ] ( 18 ); [Ni(Bu 2 Bzo 2 [14]aneN 6 )(NCS) 2 ] ( 19 ); [Ni((benzyl) 2 Bzo 2 [14]aneN 6 )(NCS) 2 ] ( 20 )} have been prepared by the in situ one-pot template synthesis (IOPTS) of formaldehyde and 1,2-phenylenediamine with alkyl amine or benzyl amine in the presence of the nickel(II) ion. The complexes of the hexaaza macrocycle have been characterized by elemental analyses, IR, FAB, UV–Vis and 1 H NMR spectroscopy, conductometric and magnetic measurements. The nickel(II) complexes {[Ni(R 2 Bzo 2 [14]aneN 6 )](ClO 4 ) 2 ( 1 – 5 ) and [Ni(R 2 Bzo 2 [14]aneN 6 )](PF 6 ) 2 ( 6 – 10 )} have square-planar coordination geometry in the solid state and in nitromethane. The spectra of all complexes show that the four secondary nitrogen atoms are coordinated to the nickel(II) ion. Synthesis, characterization and solution behavior of the nickel(II) complexes of hexaaza macrocycle ( 1 – 6 ) are reported. The stereochemistry around the metal ions in the {[Ni(R 2 Bzo 2 [14]aneN 6 )(NCS) 2 ] and “[Ni(R 2 Bzo 2 [14]aneN 6 )Cl 2 ]}” complexes is octahedral.

Six new square-planar nickel(II) complexes of 18-membered decaaza macrocyclic ligands 5,6,14,15-tetramethyl-1,3,4,7,8,10,12,13,16,17-decaazacyclooctadecane [Ni(Me 4 [18]aneN 10 )](ClO 4 ) 2 ( 1 ); 1,10-dimethyl-[Ni(Me 2 Me 4 [18]aneN 10 )](ClO 4 ) 2 ( 2 ); 1,10-diethyl-[Ni(Et 2 Me 4 [18]aneN 10 )](ClO 4 ) 2 ( 3 ); 1,10-dipropyl-[Ni(Pr 2 Me 4 [18]aneN 10 )](ClO 4 ) 2 ( 4 ); 1,10-dibutyl iso -[Ni(Bu 2 Me 4 [18]aneN 10 )](ClO 4 ) 2 ( 5 ); 1,10-dibenzyl-5,6,14,15-tetramethyl-1,3,4,7,8,10,12,13,16,17-decaazacylooctadecane [Ni((Benzyl) 2 Me 4 [18]aneN 10 )](ClO 4 ) 2 ( 6 ); [Ni(Me 4 [18]aneN 10 )](PF 6 ) 2 ( 7 ); [Ni(Me 2 Me 4 [18]aneN 10 )](PF 6 ) 2 ( 8 ); [Ni(Me 4 Me 4 [18]aneN 10 )](PF 6 ) 2 ( 9 ); [Ni(Pr 2 Me 4 [18]aneN 10 )](PF) 2 ( 10 ); [Ni(Bu 2 Me 4 [18]aneN 10 )](PF 6 ) 2 ( 11 ); [Ni((Benzyl) 2 Me 4 [18]aneN 10 )](PF 6 ) 2 ( 12 ); [Ni(Me 4 [18]aneN 10 )(NCS) 2 ] ( 13 ); [Ni(Me 2 Me 4 [18]aneN 10 )(NCS) 2 ] ( 14 ); [Ni(Et 2 Me 4 [18]aneN 10 )(NCS) 2 ] ( 15 ); [Ni(Pr 2 Me 4 [18]aneN 10 )(NCS) 2 ] ( 16 ); [Ni(Bu 2 Me 4 [18]aneN 10 )(NCS) 2 ] ( 17 ) and [Ni((Benzyl) 2 Me 4 [18]aneN 10 )(NCS) 2 ] ( 18 ) have been prepared from the one-pot template condensation reaction of formaldehyde, 2,3-butanedihydrazone with alkyl and benzyl amine in the presence of the nickel(II) ion. Elemental analyses, IR, UV–Vis spectroscopy, conductometric and magnetic measurements have been used to characterize the nickel(II) complexes of these decaaza macrocycles. The spectra of [Ni(R 2 Me 4 [18]aneN 10 )](ClO 4 ) 2 shows that the four nitrogen (α-diimine) atoms are coordinated to the nickel(II) ion. The hydrazones of the (α-diimine) function have the anti – anti configuration yielding a macrocyclic species with D 2h symmetry. The nickel(II) complexes are diamagnetic and four coordinate, exhibiting only weak interactions with different solvents. The physical and chemical properties of the complexes are compared with other closely related complexes.

A new nickel(II) complex of the 16-membered hexaaza macrocyclic ligand “1,3,7,9,11,15-hexaazacyclohexadecane, (L1); 1,9-dimethyl-, (L2); 1,9-diethyl-, (L3); 1,9-dibutyliso-, (L4); 1,9-dibutylsec-, (L5) and 1,9-dibenzyl-1,3,7,9,11,15-hexaazacyclohexadecane (L6)” have been prepared by the one-pot template reactions of formaldehyde and propylenediamine (pn) with alkyl and benzyl amine in the presence of nickel(II) ion. The complexes of a hexaaza macrocycle have been characterized by elemental analyses, IR, UV–Vis and 13C NMR spectroscopy, conductometric and magnetic measurements. The complexes of nickel(II) have square-planar coordination geometry in the solid state and in nitromethane. The spectra of [NiL1–6](ClO4)2 shows that the four secondary nitrogen atoms are coordinated to the nickel(II) ion. Synthesis, characterization and solution behavior of the nickel(II) complexes of hexaaza macrocycle are reported.