Synthesis and spectroscopic studies of complexes of zinc(II) with N2O2 donor groups

Complexes of zinc(II) with N,N'-disalicylidene-1,2-phenylenediamine (H2dsp), N,N'-disalicylidene-3,4-diaminotoluene (H2dst), 4-nitro-N,N'-disalicylidene-1,2-phenylenediamine (H2ndsp) and N,N'-disalicylidene ethylenediamine (H2salen) have been prepared and characterized by elemental analysis, electronic, IR, 1H NMR and thermal studies. TG studies show that all complexes decomposed in one step. Kinetic and thermodynamic parameters were computed from the thermal decomposition data. The activation energy of complexes lies 60-87 kJ mol(-1) range.     

Syntheses and characterization of Ru(III) with chelating containing ONNO donor quadridentate Schiff bases

Complexes of ruthenium(III) with N,N'-disalicylidene-l,2-phenylenediamine (H2dsp), N,N'-disalicylidene-3,4-diaminotoluene (H2dst), 4-nitro-N,N'-disalicylidene-1,2-phenylenediamine (H2ndsp) and N,N'-disalicylidene ethylenediamine (H2salen) have been prepared and characterized by elemental analysis, molar conductivity, spectral methods (mid-infrared, 1H NMR and UV-vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. The molar conductance measurements proved that all these complexes are non-electrolytes. The electronic spectra measurements were used to infer the structures. The IR spectra of the ligands and their complexes are used to identify the type of bonding. The kinetic thermodynamic parameters such as: E*, DeltaH*, DeltaS* and DeltaG* are estimated from the DTG curves. The four ligands and their complexes have been studied for their possible biological antifungal activity.     

Some new cobalt(II) complexes: Synthesis,characterization and thermal studies

Cobalt(II) complexes of tetradentate Schiff bases of the type CoL [H₂L=C₂₀H₁₆N₂O₂ (H₂dsp), C₂₁H₁₈N₂O₂ (H₂dst), C₂₀H₁₅N₃O₄ (H₂ndsp) and C₁₆H₁₆N₂O₂ (H₂salen)] have been synthesized and characterized by UV-visible, IR, and magnetic studies. Various thermodynamic parameters have been calculated for the decomposition step using TG/DTA. C₂₀H₁₄N₂O₂Co complex has the minimum and C₁₆H₁₄N₂O₂Co complex has the maximum activation energy.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis,characterization, anticancer activity,thermal and electrochemical studies of some novel uranyl Schiff base complexes

Some tetradentate N₂O₂ Schiff base ligands, such as N,N′-bis(naphtalidene)-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-methyl-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-chloro-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-nitro-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-carboxyl-1,2-phenylenediamine, and their uranyl complexes were synthesized and characterized by ¹H NMR, IR, UV–Vis spectroscopy, TG (thermogravimetry), and elemental analysis (C.H.N.). Thermogravimetric analysis shows that uranyl complexes have very different thermal stabilities. This method is used also to establish that only one solvent molecule is coordinated to the central uranium ion and this solvent molecule does not coordinate strongly and is removed easier than the tetradentate ligand and also trans oxides. The electrochemical properties of the uranyl complexes were investigated by cyclic voltammetry. Electrochemistry of these complexes showed a quasireversible redox reaction without any successive reactions. Also, the kinetic parameters of thermal decomposition were calculated using Coats–Redfern equation. According to Coats–Redfern plots the kinetics of thermal decomposition of the studied complexes is first-order in all stages. Anticancer activity of the uranyl Schiff base complexes against cancer cell lines (Jurkat) was studied and determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide) assay.     

Copper(II) complexes of new biomimetic polydentate amide ligands: a spectroscopic study

Complexes of Cu(II) with N,N'-bis(3-carboxy-1-oxopropanyl)-1,2-ethylenediamine(C(10)H(16)N(2)O(6),L(1)), N,N'-bis(3-carboxy-1-oxopropanyl)-1,2-phenylenediamine(C(14)H(16)N(2)O(6),L(2)), N,N'-bis(2-carboxy-1-oxophenelenyl)-1,2-phenylenediamine(C(22)H(16)N(2)O(6),L(3)) and N,N'-bis(3-carboxy-1-oxoprop-2-enyl)-1,2-phenylenediamine(C(14)H(12)N(2)O(6),L(4)) have been prepared and characterised by elemental analyses, vibrational spectra, magnetic susceptibility measurements, ligand field spectra, EPR spectra, thermal studies and X-ray diffraction spectra. Vibrational spectra indicate coordination of amide and carboxylate oxygens of the ligands giving a MO(4) square planar chromophore. Ligand field and EPR spectra support square planar geometry around Cu(II). [Cu(L(1))] complex has the maximum activation energy and [Cu(L(3))] complex has the minimum activation energy.     

Synthesis, Crystal Structure and Electrochemistry Properties of a (N,N'-Ethylene-bis(salicylaldiminato)) Nickel(II) Complex, [Ni_2(salen)_2]·NCS·NH_4

A new Ni(II) complex [Ni2(salen)2]·(NCS)·NH4 (salen = N,N’-bis(salicylidenea- mino)ethanato) has been prepared and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.8725(13), b = 19.0046(15), c = 20.0583(16) , Z = 8, V = 6431.8(9) 3, C33H32N6Ni2O4S1, Mr = 726.13, Dc = 1.500 g/cm3, F(000) = 3008, μ = 1.284 mm-1, the final R = 0.0394 and wR = 0.0767 for 4449 observed reflections with I > 2σ(I). The complex involves a N,N’-ethylene-bis(salicylaldiminato) Schiff base, an isothiocyanato anion and an ammonium cation. The nickle(II) ion adopts a distorted square coordination geometry with N2O2 set of Schiff base ligand. The complexes are linked into a dimmer via intermolecular hydrogen bonds and the [Ni(salen)] moieties are connected together to form a 2-D layer structure by intermolecular N–H…O hydrogen bonds and π-π stacking. Cyclic-voltammetry method was used to characterize electrochemically the complex.     

Ferromagnetic interactions in Ru(III)-nitronyl nitroxide radical complex: a potential 2p4d building block for molecular magnets

The reaction between [Ru(salen)(PPh3)Cl] and the 4-pyridyl-substituted nitronyl nitroxide radical (NITpPy) leads to the [Ru(salen)(PPh3)(NITpPy)](ClO4)(H2O)2 complex while the reaction with the azido anion (N3-) leads to the [Ru(salen)(PPh3)(N3)] complex 2 (where salen2- = N,N'-ethan-1,2-diylbis(salicylidenamine) and PPh3 = triphenylphosphine). Both compounds have been characterized by single crystal X-ray diffraction. The two crystal structures are composed by a [Ru(III)(salen)(PPh3)]+ unit where the Ru(III) ion is coordinated to a salen2- ligand and one PPh3 ligand in axial position. In 1 the Ru(III) ion is coordinated to the 4-pyridyl-substituted nitronyl nitroxide radical whereas in 2 the second axial position is occupied by the azido ligand. In both complexes the Ru(III) ions are in the same environment RuO2N3P, in a tetragonally elongated octhaedral geometry. The crystal packing of 1 reveals pi-stacking in pairs. While antiferromagnetic intermolecular interaction (J2 = 5.0 cm(-1)) dominates at low temperatures, ferromagnetic intramolecular interaction (J1 = -9.0 cm(-1)) have been found between the Ru(III) ion and the coordinated NITpPy.     

Synthesis,Characterization and Crystal Structure of One Ni_2（salen）_2 Complex

A homochiral complex,Ni 2 (salen) 2 (1,salen=(R,R)-(-)-N,N-bis(3-tert-butyl-5-(4ethynylpyridyl)salicyl-idene)-1,2-diaminocyclohexane),has been synthesized and characterized by IR,microanalysis,CD spectra,TGA,powder and single-crystal X-ray crystallography.It crystallizes in triclinic,space group P1 with a=11.896(2),b=12.571(3),c=13.197(3),α=65.61(3),β=73.90(3),γ=75.87(3)o,V=1707.9(6) 3,Z=2,C 42 H 42 N 4 NiO 2,M r=693.51,D c=1.349 g/cm 3,F(000)=732,μ=0.612 mm-1,GOOF=1.015,the final R=0.0290 and wR=0.0796 for 9002 observed reflections with I > 2σ(Ⅰ).The complex architecture is constructed by intermolecular π···π interaction and assembled into a 2D structure via C-H···π interactions between the cyclohexanes and pyridine rings.     

Preparation and Thermal Decomposition of [Cr (salen) (H_2O)_2] Cl

Chromium(III)isanessentialtraceelement.Inanactiveform.chronlium(III)asacomponentofglucosetolerancefactor(GTF)canimproveinsulinbiologicalactivity.CrsupplementationinhumansandanimalsreducessymptomsofTypeIIdiabetesandhypoglycemia.Forabetterunderstandingofthenatureofbiologicallyactivechromium(ill)complex,manyGTFmodelcomplexeshavebeenstudiedpreviously'.Here,oneGTFmodelcomplexofN,N'-ethylenebis(salicylideneiminato)diaquochromium(ill)chloride,[Cr(salen)(H,O)=]CIwaspreparedandcharacterized.a…     

Aluminum salen complexes and tetrabutylammonium salts: a binary catalytic system for production of polycarbonates from CO2 and cyclohexene oxide

A series of complexes of the form (salen)AlZ, where H2salen = N,N'-bis(salicylidene)-1,2-phenylenediimine and various other salen derivatives and Z = Et or Cl, have been synthesized. Several of these complexes have been characterized by X-ray crystallography. An investigation of the utilization of these aluminum derivatives along with both ionic and neutral bases as cocatalysts for the copolymerization of carbon dioxide and cyclohexene oxide has been conducted. By studying the reactivity of these complexes for this process as substituents on the diimine backbone and phenolate rings are altered, we have observed that aluminum prefers electron-withdrawing groups on the salen ligands, thereby producing an electrophilic metal center to be most active toward production of polycarbonates from CO2 and cyclohexene oxide. For example, the complex derived from H2salen = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylenediimine is essentially inactive when compared to the analogous derivative containing nitro substituents in the 3-positions of the phenolate groups. This is to be contrasted with the catalytic activity observed for the (salen)CrX systems, where electron-donating salen ligands greatly enhanced the reactivity of these complexes for the coupling of CO2 and epoxides. While (salen)AlZ complexes are capable of producing poly(cyclohexene oxide) carbonate with low amounts of polyether linkage along with small quantities of cyclic carbonate byproducts, their reactivities, covering a turnover frequency range of 5.2-35.4 mol of epoxide consumed/(mol of Al x h), are greatly reduced when compared to their (salen)CrX analogues under identical reaction conditions.     

Toward rational control of metal stoichiometry in heterobimetallic coordination complexes: synthesis and characterization of Pb(Hsal)2(Cu(salen*))2, [Pb(NO3)(Cu(salen*))2](NO3), Pb(OAc)2(Cu(salen*)), and [Pb(OAc)(Ni(salen*))2](OAc)

The ability of the transition metal complex M(salen)* (M = Ni, Cu) to form Lewis acid-base adducts with lead(II) salts has been explored. The new complexes Pb(Hsal)(2)(Cu(salen*))(2) (1), [Pb(NO(3))(Cu(salen*))(2)](NO(3)) (2), Pb(OAc)(2)(Cu(salen*)) (3), and [Pb(OAc)(Ni(salen*)(2)](OAc) (4) (Hsal = O(2)CC(6)H(4)-2-OH, salen* = bis(3-methoxy)salicylideneimine) have been synthesized and characterized spectroscopically and by single-crystal X-ray diffraction. The coordination environment of the lead in the heterobimetallic complex is sensitive both to the initial lead salt and to the transition metal salen* complex that is employed in the synthesis. As a result, we have been able to access both 2:1 and 1:1 adducts by varying either the lead salt or the transition metal in the heterobimetallic coordination complex. In all cases, the salen* complex is associated with the lead center via dative interactions of the phenolic oxygen atoms. The relationship between the coordination requirements of the lead and the chemical nature of the anion is examined. In compound 1, the Pb(2+) ion is chelated by two Cu(salen*) moieties, and both salicylate ligands remain attached to the lead center and bridge to the Cu(2+) ions. The two Cu(salen*) groups are roughly parallel and opposed to each other as required by crystallographic inversion symmetry at lead. In contrast, the two Cu(salen*) groups present in 2 and 4 attached to the lead ion show considerable overlap. Furthermore, only one nitrate ion in 2 and one acetate ion in 4 remain bonded to the lead center. Compound 3 is unique in that only one Cu(salen*) group can bind to lead. Here, both acetate ligands remain attached, although one is chelating bidentate and the other is monodentate.     

Dioxomolybdenum(VI) complex with N,N′- ethylenebis(salicylideneimine)

The interaction of N,N′-ethylenebis(salicylideneimine), H₂salen, with ammonium molybdate yielded the molybdenum(VI) complex MoO₂(salen) with the cis-dioxostructure as inferred from IR spectral studies. The ¹H NMR chemical shifts of azomethine protons in the free ligand and the complex are 8.14 and 8.39 δ, respectively, suggesting the bonding of the azomethine nitrogen to MoO₂ group. The thermal decomposition behaviour of the complex is discussed.     

Syntheses,Crystal Structures,and Properties of Four Coordination Compounds with Sulfonate-Naphthol Ligand

Russian Journal of General Chemistry - Four coordination compounds, [Zn(ndsp)(bipy)2(H2O)]2·2H2O (1), Mn(ndsp)(bipy)2(H2O)·H2O (2), Ni(ndsp)(bipy)2(H2O) (3),...     

Synthesis, Crystal Structure and Electrochemistry Properties of a (N,N''-Ethylene-bis(salicylaldiminato)) Nickel(Ⅱ) Complex, [Ni2(salen)2]·NCS-NH4

A new Ni(Ⅱ) complex [Ni2(salen)2]·(NCS)·NH4 (salen = N,N'-bis(salicylidenea-mino)ethanato) has been prepared and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.8725(13), b = 19.0046(15), c = 20.0583(16) (A), Z = 8, V = 6431.8(9) (A)3, C33H32N6Ni2O4S1, Mr= 726.13, Dc = 1.500 g/cm3, F(000) = 3008, μ = 1.284 mm-1, the final R = 0.0394 and wR = 0.0767 for 4449 observed reflections with Ⅰ＞2σ(Ⅰ). The complex involves a N,N'-ethylene-bis(salicylaldiminato) Schiff base, an isothiocyanato anion and an ammonium cation. The nickle(Ⅱ) ion adopts a distorted square coordination geometry with N2O2 set of Schiff base ligand. The complexes are linked into a dimmer via intermolecular hydrogen bonds and the [Ni(salen)] moieties are connected together to form a 2-D layer structure by intermolecular N-H…O hydrogen bonds and π-π stacking. Cyclic-voltammetry method was used to characterize electrochemically the complex.     

Thermal decomposition of Pr[(C_5H_8NS_2)_3(C_(12)H_8N_2)]

The thermal behavior of the complex Pr[(C5H8NS2)3(C12H8N2)] in a dry nitrogen flow was examined by TG-DTG analysis. The TG-DTG investigations indicated that Pr[(C5H8NS2)3-(C12H8N2)] was decomposed into Pr2S3 and deposited carbon in one step where Pr2S3 predominated in the final products. The results of non-isothermal kinetic calculations showed that the decomposition stage was the random nucleation and subsequent growth mechanism (n = 2/3), the corresponding apparent activation energy ?was 115.89 kJ·mol-1 and the pre-expo-nential constant ln[A/s] was 7.8697. The empirical kinetics model equation was proposed as/(α) =3/2(1-α)[-ln(1-α)]1/3.The X-ray powder diffraction patterns of the thermal decomposition products at 800℃under N2 atmosphere show that the product can be indexed to the cubic Pr2S3 phase. The transmission electron microscopy (TEM) of the final product reveals the particle appearance of a diameter within 40 nm. The experimental results show that the praseodymium sulfide nanocrystal can be prepared from thermal decomposition of Pr[(C5H8NS2)3(C12H8N2)].     

[Ni(PMBPTSC)(H2PMBPTSC)]·C2H5OH·2H2O的合成、 结构和非等温热分解动力 学

报道了标题配合物[Ni(PMBPTSC)(H2PMBPTSC)]·C2H5OH·2H2O的制备,晶体结构及非等温热分解动力学,该晶体属单斜晶系,空间群Pn,a=1.0376(3)nm,b=1.1522(3)nm,c=1.7591(3)nm;β=90.75(2)°;V=2.1028(8)nm^3;Z=2,Dc=1.329g/cm^3;μ=0.614mm^-1;F(000)=880.根据TG-DTG曲线,运用Achar法与Coats-Redfer法对配合物第一步热分解反应进行了非等温热分解动力学研究,其机理为三维扩散机理,动力学方程为da/dt=Ae^-E/RT3/2(1-α)^2/3[1-(1-α)^1/3]^-1,动力学补偿效应表达式为lnA=0.307915E-1.20469.     

Thermal behavior of Mannich base N,N′-tetra(4-antipyrylmethyl)-1,2 diaminoethane (TAMEN) and its binuclear complexes

The thermal decomposition of Mannich base N,N′-tetra(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN), and its Ni(II), binuclear complex, Ni₂(TAMEN)Cl₄, in air and in nitrogen atmosphere, were investigated. X-ray powder diffractometry, infrared spectroscopy and simultaneous thermogravimetry-differential thermal analysis (TG-DTA), have been used to characterize and to study the thermal behavior of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and decomposition mechanism of the compound.     

X-Ray crystal structures of five-coordinate (salen)MnN3 derivatives and their binding abilities towards epoxides: chemistry relevant to the epoxide-CO2 copolymerization process

The synthesis of several (salen)MnN(3) complexes in good yields and purities were achieved by the reaction of manganese(iii) acetate and H(2)salen, followed by metathesis of the remaining acetate ligand with an aqueous solution of NaN(3). The X-ray structures of two derivatives, where salen = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylenediamine and N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexenediamine respectively, were determined. The complexes were shown to be monomeric 5-coordinate derivatives displaying a distorted square pyramidal geometry, and to be d(4) high-spin derivatives by solution magnetic moment measurements using the Evans method. Binding studies of the (salen)MnN(3) derivatives with added azide ions or cyclohexene oxide showed these complexes to have modest affinities for binding a sixth ligand. These observations are used to rationalize the low activity exhibited by manganese(iii) complexes relative to their chromium(iii) and cobalt(iii) analogs for serving as catalysts for the copolymerization of carbon dioxide and epoxides.     

Heterometallic MIIRuIII2 compounds constructed from trans-[Ru(Salen)(CN)2]- and trans-[Ru(Acac)2(CN)2]-. Synthesis, structures, magnetic properties, and density functional theoretical study

The synthesis, structures, and magnetic properties of four cyano-bridged M(II)Ru(III)2 compounds prepared from the paramagnetic Ru(III) building blocks, trans-[Ru(salen)(CN)2]- 1 [H2salen = N,N'-ethylenebis(salicylideneimine)] and trans-[Ru(acac)2(CN)2]- (Hacac = acetylacetone), are described. Compound 2, {Mn(CH3OH)4[Ru(salen)(CN)2]2}.6CH3OH.2H2O, is a trinuclear complex that exhibits antiferromagnetic coupling between Mn(II) and Ru(III) centers. Compound 3, {Mn(H2O)2[Ru(salen)(CN)2]2.H2O}n, has a 2-D sheetlike structure that exhibits antiferromagnetic coupling between Mn and Ru, leading to ferrimagnetic-like behavior. Compound 4, {Ni(cyclam)[Ru(acac)2(CN)2]2}.2CH3OH.2H2O (cyclam = 1,4,8,11-tetraazacyclotetradecane), is a trinuclear complex that exhibits ferromagnetic coupling. Compound 5, {Co[Ru(acac)2(CN)2]2}n, has a 3-D diamond-like interpenetrating network that exhibits ferromagnetic ordering below 4.6 K. The density functional theory (DFT) method was used to calculate the molecular magnetic orbitals and the magnetic exchange interaction between Ru(III) and M(II) (Mn(II), Ni(II)) ions.     

Synthesis, spectroscopic studies and electrochemistry of palladium (II) macrocyclic complexes derived from a new tetraazahalogen substituted ligands by template method and their antimicrobial and pesticidal activities

A new series of Pd(II) macrocyclic complexes have been synthesized by template condensation of bis(benzil)4-chloro 1,2-phenylenediamine (ML1) and bis(benzil)4-fluro 1,2-phenylenediamine (ML2) respectively, with appropriate diamine i.e. 1,2-phenylenediamine, 4-chloro 1,2-phenylenediamine and 4-fluro 1,2-phenylenediamine in the presence of PdCl2 to form complexes of the type [Pd(C40H26N4ClF)]Cl2, [Pd(C40H27N4X)]Cl2 and [Pd(C40H26N4X2)]Cl2, where X=Cl, F. The complexes have been characterized with the help of elemental analysis, IR, 1H NMR, electronic spectra, conductance measurement, magnetic susceptibility, cyclic voltammetry and X-ray powder diffraction studies. On the basis of these studies a square planar geometry has been proposed around the metal ion. The newly synthesized ligands and their complexes have been screened for antimicrobial and pesticidal activities. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substance with pesticidal activity and promising antimicrobial activity.