Syntheses,Crystal Structures and Kinetic Mechanisms of Thermal Decomposition of Rare Earth Complexes with Schiff Base Derived from o-Vanillin and p-Toluidine

Three complexes, [Pr（NO3）3（HL）2] （1）, [Nd（NO3）3（HL）2] （2） and [Er（NO3）3（HL）2] ·0.5H2O （3）, were synthesized from the reaction of a Schiff base ligand 2-[ （4-methylphenylimino）methyl ]-6-methoxyphenol （C15 H15 NO2, HL） with Ln（NO3）3·6H2O （Ln = Pr, Nd, Er）. Characterization by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, ^1H NMR and thermal analysis shows the title complexes are neutral molecules where the central Ln（ Ⅲ） ion is ten-coordinated in biapical anti-hexahedron prism geometry, with four oxygen atoms of the phenolic hydroxy and methoxy groups in the two bidentate Schiff base ligands and six oxygen atoms provided by the three bidentate NO3 - anions. Additionally, the kinetic mechanism of thermal decomposition of complex 3 was determined with a TG-DTG curves by both integral and differential methods. The functions of thermal decomposition reaction mechanism and the equation of kinetic compensation effect were obtained.

Synthesis, Catalysis of Rare Earth Complexes with Aliphatic Noncyclic Polyether-Amino Acid Schiff Base

Eleven new rare earth complexes with aliphatic Schiff base, condensed from diglycol aldehyde and bis-arginine, were synthesized and characterized. They are confirmed as Ln （H2DAAR） （NO3）3·7H2O （ Ln = La, Pr, Nd, Gd）, Ln3 （H2DAAR）2（NO3）9·5H2O （Ln= Dy, Y）and Ln2（H2DAAR）（NO3）6·3H2O （Ln = La, Nd, Sm, Gd）, Ln3（DAAR） （NO3）7·4H2O （Ln = Dy, Yb, Y） respectively under different molar ratios of metal to ligand （DAAR = diglycol aldehyde bis-arginine）. The present paper deals with a synthetic method and catalytic properties of obtained complexes. The result shows that proper pH value is important for synthesis of the complexes and compositions of the lighter and the heavier rare earth complexes are different under the same reaction condition. Some new complexes obtained have proved their catalytic activity and 80% conversion with the viscosity-average molecular weight 230,000 for the polymerization of methyl methacrylate （MMA） without addition of any cocatalyst.

Synthesis, characterization, and anticancer properties of rare earth complexes with Schiff base and o-phenanthroline

Five novel ternary complexes of the rare earth ions with o-phenanthroline（Phen） and Schiff base salicylaldehyde L-phenyla- lanine（KHL） were synthesized in ethanol. Their compositions were characterized by elemental analysis, molar conductance, ^1H NMR, FT-IR, and Raman spectra. The formulas of the complexes were verified to be RE（L）（Phen）Cl（H2O） （RE=La^3＋, Ce^3＋, Nd^3＋, Er^3＋, and Gd^3＋; L=Schiff base salicylaldehyde L-phenylalanine; phen=o-phenanthroline）. Methyl thiazolyl tetrazolium （MTT） colorimetry and flow cytometry were used to test the anticancer effect of the complexes with K562 tumor cell. The research showed that the complexes could inhibit K562 tumor cell＇s growth, generation, and induce apoptosis. The inhibition ratio was accelerated by increasing the dosage, and it had significant positive correlation with the medication dosage.

Synthesis, Characterization and Activity of Rare Earth Complexes with Schiff Base From 2,6-Diformylpyridine N-Oxide and 4-Amino-antipyrine

Six new rare earth complexes with Schiff base from 2,6 diformylpyridine N oxide and 4 amino antipyrine were synthesized. These complexes with general formula REL(NO 3) 3 (RE=La, Pr, Eu, Tb, Er, Y) were characterized by elemental analysis, IR, UV, molar conductance measurements and antimicrobial activity.

Syntheses, Characterizations, Crystal Structures and Antibacterial Activities of Two Zinc(II) Complexes with a Schiff Base Derived from o-Vanillin and p-Toluidine

Two new zinc（Ⅱ） complexes, [Zn2L2Ch].2[ZnL（CH3OH）Cl2] 1 and [ZnL2（NO3）2] 2, were synthesized by reacting ZnX2.nH2O （X = Cl^-, NO3^-） and a Schiff base ligand 2-[（4-methylphenylimino）methyl]-6-methoxyphenol （C15HIsNO2, L） which was obtained by the condensation of o-vanillin （2-hydroxy-3-methoxybenzaldehyde） with p-toluidine. Both 1 and 2 were characterized by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, IH-NMR spectra and thermogravimetrie analysis. The Schiff base ligand and its zinc（Ⅱ） complexes have been tested in vitro to evaluate their antibacterial activity against bacteria, viz., Escherichia Coli, Staphylococcus aureus and Bacillus Subtilis. The results show that these complexes have higher activity than the corresponding free Schiff base ligand against the same bacteria.

COMPLEXES OF RARE EARTH NITRATE WITH SCHIFF BASE DERIVED FROM VANILLIN AND P-TOLUIDINE

In this paper,complexes of rare earth nitrate with Schiff base derived from vanillin(3-methoxy-4-hydroxy-benzaldehyde)and p-toluidine[LnL_2(NO_3)_2]NO_3(Ln=La-Eu except Pm,L=Schiff base ligand) have been prepared and characterized.

Synthesis and Characterization of Lanthanum Complexes with Amino Acid Schiff Base

Six new complexes of lanthanum with amino acid Schiff base ligands, A-F, were prepared in methanol-aqueous solution. The composition and properties of the title complexes were characterized by elemental analysis, molar conductance, infrared, electronic spectra, H-1 NMR, thermogravimetric and differential thermal analysis.

Synthesis and characterization of lanthanide complexes containing a bulky tridentate [N,N,O] Schiff base ligand

The lanthanide complexes containing a bulky tridentate [N,N,O] Schiff base ligand 3,5-But2-2-（OH）C6H2CH=N-8-C9H6N （HL） were synthesized and characterized. The reaction of anhydrous LnCl3 with NaL formed in situ in a 1：1 molar ratio in THF at room temperature afforded the lanthanide Schiff base dichloride complexes LnLCl2（DME） （Ln=Eu （1）; Sm （2））. Complexes 1 and 2 can be used as precursors for the synthesis of the lanthanide cyclopentadienyl Schiff base derivatives. The reactions of complexes 1 and 2 with one equiv of NaCH3C5H4 in THF provided the desired products LnL（CH3C5H4）CI（THF）.THF （Ln=Eu （3）; Sm （4）） in good isolated yields. These complexes were characterized by elemental analysis, IR spectra, and X-ray structural determination, in the case of complexes 3 and 4. The crystal data of complex 3 are monoclinic, P21/C space group, a=1.3370（2） nm, b=1.5190（2） nm, c=1.8910（3） nm, β=109.846（4）°, V=3.6125（8） nm^3, Z=4, Dc=1.416 mg/m^3,μ=1.847 mm^-1, F（000）=1584, R=0.0707, wR=0.1350. The crystal data of complex 4 are monoclinic, P21/c space group, a=1.3383（1） nm, b=1.5210（2） nm, c=1.8960（2） nm, β =109.878（3）°, V=3.6293（7） nm^3, Z=4, Dc=1.407 mg/m^3, μ=1.728 mm^-1, F（000）= 1580, R=0.0670, wR=0.1385.

Synthesis and Application of Lanthanide Complexes with Schiff Base of Pridoxylidence-Glycine

A series of novel rare earths complexes with Schiff base of pridoxylidence-glycine acid (HL) were synthesized in absolute methanol under argon atmosphere. The complexes were characterized by elemental analysis, molar conductivity, IR, UV spectra, and H-NMR spectra et al. Data indicate that the complexes have a general formula Ln LCl2.3H(2)O (Ln = La, Y, Sm, Gd, Dy, Yb; L = C10H11N2O4). Effects of the complexes (Ln = La) on physiological and biochemical indexes of plants under Pb stress were studied. The experiments shown that the complexes obviously mitigated Pb pollution results in decreasing of chlorophyll content, rising of cell membrane permeability, changing catalase(CAT) and distribution of Pb.

Synthesis and Characterization of New Schiff Base and Polyoxa-azaCryptands and Their Rare Earth Cryptates with [1+1] Condensation and Reduction Methods

The Schiff base cryptand and its cryptates were synthesized with the methods of [1+1] condensation of trialdehyde and tris(2-aminoethyl)amine and obtained in 60-65%, 5-25% and 70-80% yields respectively with or without some rare earth elements as templates. The polyoxa-aza cryptand was produced in 72% and 60-70% yields with reduction of Schiff base and its cryptates respectively.

Syntheses and Characterizations of Cu Ln Heterobinuclear Complexes with Schiff Base from 3-Formylsalicylic Acid and Ethylene Diamine

Seven heterobinuclear complexes of Cu-Ln with N, N'-bis(3-carboxylsali cylidene) ethylenediamine(ES) were synthesized and characterized by elemental analysis, molar conductivity, thermogravimetry, IR and electronic spectra. The room temperature magnetic moments show that there are basically no spin exchange interactions between the ions of Cu2+ and Ln(3+) in the CuLnESCl . nH(2)O compounds.

Synthesis and Thermal Decomposition Kinetics of La(Ⅲ) Complex with Unsymmetrical Schiff Base Zwitterion Ligand

A new unsymmetrical solid Schiff base (LLi) was synthesized using L-lysine, o-vanillin and 2-hydroxy-l-naphthaldehyde. Solid La(Ⅲ) complex of this ligand [LaL(NO3)](NO3)·2H2O was prepared and characterized by elemental analyses, IR, UV and molar conductance. The thermal decomposition kinetics of the complex for the second stage were studied under non-isothermal condition by TG and DTG methods. The kinetic equation may be expressed as: dα/dt=A·e-E/RT·(1-α)2. The kinetic parameters(E, A), activation entropy S≠ and activation free-energy G≠ were also gained.

HETEROCYCLIC SCHIFF BASE NEODYMIUM COMPLEX AS CATALYST FOR RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE

An aromatic heterocyclic Schiff base neodymium complex bearing thiazole was synthesized and its activity in the ring-opening polymerization ofε-caprolactone(CL)was examined.The conditions of the CL/Nd molar ratio,monomer concentration,polymerization time and temperature were investigated.Activities of ca.171 kg/Nd·h were obtained under the optimum condition(CL/Nd=1600(molar ratio),[CL]=2.26 mol L^(-1),1 h at 50℃),giving a poly(ε-caprolactone)(PCL)of number-average molecular weight M_n=5.4×10~4 and molecular...

Rare earth complexes with noncyclic polyether-methionine Schiff base

A novel Schiff base (TAMET) was synthesized by the condensation of tetraglycol aldehyde with methionine and a mild oxidant CrO3. (C5H5N)2 was selected for the reaction. Seven new rare earth complexes with this Schiff base have been synthesized and characterized by elemental analysis, TG-DTA, molar Conductivity, magnetic susceptibility and IR, especially 1H NMR spectra. Information was obtained from reflectance spectra and the coordination of sulfur atom to rare earths was discussed. The experimental results show that these compounds have some biological activity and could dispose of O2?-.

Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H2salen)2Cl3·2C2H7OH/Al(i-Bu)3) at room temperature was investigated. The influences of ligand structure, catalyst composition, polymerization temperature, polymerization time, the concentration of catalyst and monomer, and the polymerization solvent on the polymerization of isocyanates were studied. It was found that under the polymerization conditions, examined La(H2salenA)2Cl3·2C2-H7OH/Al(i-Bu)3 (H2salenA= N,N′-disalicylideneethylene diamine) is a fairly high efficient catalyst for the polymerization of n-hexyl isocyanate (n-HexNCO) to prepare high molecular weight poly(n-hexyl isocyanate) (PHNCO) with narrower molecular weight distribution at room temperature. PHNCO could be prepared with yield of 74.0%, number-average molecular weight (M n) of 40.20×104 and MWD of 1.79 under the following optimum conditions: [Al]/[La] = 30 (molar ratio), [n-HexNCO]/[La] = 100 (molar ratio), [n-HexNCO] = 3.43 mol/L polymerization at 20°C for 12 h in toluene. In the same polymerization conditions, poly (n-octyl isocyanate) (PONCO) with yield of 67.3%, and poly(n-butyl isocyanate) (PBNCO) with yield of 45.5%, could be prepared respectively. The kinetics of the polymerization of n-HexNCO was also investigated and found to be first-order with respect to both monomer and catalyst concentrations.

Synthesis, Characterization and Bioactivity of Complexes of Rare Earth with Bis-Schiff Base from Furoylpyrazolone

Eleven new complexes of rare earths with bis-Schiff base derived from N,N'-bis[(1-phenyl-3-methyl-5-oxo-4-pyrazolinyl) alpha-furylmethylidyne] ethylenediimine ((HPM alpha FP)(2)en) were synthesized. On the basis of elemental analysis and molar conductance, a general formula of the complexes, [RE(HPM alpha FP)(2)en(NO3)(2)]NO3(RE = La, Pr, Nd, Sm, Eu, Th, Dy, Ho, Er, Yb,Y), was given. The complexes were characterized by IR, UV-visible, H-1 NMR, C-13 NMR and fluorescence. The results show that the bis-Schiff base is a quadridentate ligand and the rare earth ions exhibit coordination of eight in the complexes. The antibacterial experiments indicate that they have high antibacterial activities against S. aureus, B. subtillis, E. coli, E. carotovora, C. flaccumfaciens.

Synthesis of 4-acylpyrazolone Schiff base ligand grafted silica and selectivity in adsorption of lanthanides from aqueous solutions

The Schiff base form of the 4-acylpyrazolone ligand was immobilized on the silica surface by reaction of 3-aminopropyl silica with 4-acetyl-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one in 97% yield, producing grafted silica with 0.77 mmol/g ligand loading. This surface modified silica was shown to be selective in the adsorption of Yb3+ ions from dilute aqueous solutions, for which 98% adsorption was observed from a 1.0×10-5 mol/L aq. solution at pH 6.7, after 24 h at room temperature. Six other lanthanides studied Eu3+, Gd3+, Nd3+, Tb3+, Sm3+ and La3+ showed moderate to weaker adsorptions of 39%, 28%, 16%, 12%, 11% and 5% respectively under similar conditions.

Studies on Heterobinuclear Complexes of Ln^(3+) and Zn^(2+) with Acyclic Polyether Schiff Base

Eight novel heterobinuclear complexes of Ln3+ and Zn2+ with salicylidene diethylene glycol diamine(SALDA) Schiff base (NO3)22H2O(Ln=Pr, Nd, Sm, Gd, Tb, Er, Yb, Y) were synthesized and characterized on the basis of IR and UV, particularly by1H and13C NMR spectra. It is confirmed that the azomethine nitrogen, ethereal oxygen and a part of phenolic oxygen atoms coordinate to the central ions.

Construction of NIR luminescent nanoscale lanthanide complexes with new flexible Schiff base ligands

Four mono-and bi-nuclear lanthanide complexes [LnL1(No3)(H2O)DMF](Ln=Nd(1) and Yb(2)) and[Ln2(L2)2(OAc)2](Ln=Nd(3) and Yb(4)) were synthesized by using two new Schiff base ligands with long(CH2)2 NH(CH2)2 backbone.The lengths of the Schiff base ligands are about 1.8 nm.The bi-nuclear lanthanide complexes 3 and 4 have nanoscale structures with sizes of approximately 0.7 nm×1.1 nm×1.6 nm.For 3,the molar ratio of Nd:Br:O obtained by the energy dispersive X-ray spectroscopy analysis is in agreement with the crystal structure.The chromogenic Schiff base ligands in1-4 can efficiently transfer energy to lanthanide ions,thus,these complexes exhibit the typical NIR luminescence of lanthanide ions.Interestingly,3 and 4 have higher NIR emission quantum yields(Φem)than 1 and 2,respectively.

Synthesis and catalytic activity of Ln (III) complexes with an unsymmetrical Schiff base including multi“非汉字符号” C=N—groups

A synthetic method for a new unsymmetrical Schiff base and its Ln(Ⅲ)complexes including multi > C = N — groups is reported. The complexes are characterized byelemental analysis, IR spectra, ~1H and ^(13)C NMR, especially 2D-COSY ~1H, ~1H NMR spectra. Thegeneral formula of the obtained complexes is [Ln_3(TBLY)(NO_3)_3] · nH_2O (Ln = La, n = 3; Ln = Nd,n=5; Ln = Gd, Dy, Yb, Y, n = 7), where TBLY = tetraglycol aldehyde-2,4-dihydroxy benzaldehydebis-lysine Schiff base. In addition, the evidence for existence of > C = CH — NH — group issupported by the AM1 method. The complexes obtained may be used as a catalyst. Conversion rate of80% with the viscosity-average molecular weight 220000 for the polymerization of methyl methacrylate(MMA) without addition of any cocatalyst has been obtained.