Preparation, characterization and luminescence behavior of some samarium complexes

The synthesis of luminescent complexes of Sm(III) with the general formula [Sm(L)_(3)·(X)] was done in powder form. In the formula, L is 6-methyl-4-oxo-4 H-1-benzopyran-3-carboxaldehyde and X represents 2H_(2)O(C1), 1,10-phenanthroline(C2), 2,20-bipyridine(C3);bathophenanthroline(C4) and neocuproine(C5). The complexes were characterized by using various analytical and spectroscopic tools like elemental analysis, electrospray ionization mass spectrometry(ESI–MS+), Fourier transform infrared spectroscopy(FTIR), ultraviolet–visible(UV–Vis) spectroscopy, thermo-gravimetric analysis/differential thermal gravimetric analysis(TGA/DTG), field emission scanning electron microscopy(FESEM), powder X-ray diffraction(XRD), and photoluminescence(PL)studies. TGA/DTG showed high thermal stability of synthesized complexes. Powder XRD depicts that the average particle size lies in the nano-range. On monitoring at the excitation wavelength of 370 nm, the complexes display characteristic luminescence peaks of Sm(III) at ~564,~600 and ~647 nm assigned to^(4)G_(5/2)→^(6)H_(5/2),^(4)G_(5/2)→^(6)H_(7/2), and ^(4)G_(5/2)→6H9/2 transitions, respectively, with the most intense transition at ~600(orange emission) and~647 nm(bright red emission) in liquid and powder state, respectively. The investigations demonstrate that the synthesized novel complexes might be practically useful in electroluminescent devices, bio-assays, and liquid lasers due to their attractive photoluminescent properties.

Thermochemical Study on Coordination Complex of Samarium with Salicylic Acid and 8-Hydroxyquinoline

The coordination complex Sm（C7H5O2）2·（C9H6NO）, synthesized from the reaction of samarium chloride sixhydrate with salicylic acid and 8-hydroxyquinoline, was characterized with IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [ SmCl3·6H2O （s） ], [ 2C7H6O3 （s） ], [ C9H7NO （ s ） ] and [ Sm （C7H5O3） 2·（ C9H6NO ） （ s ） ] in the calorimetric solvent were determined with the solution-reaction isoperibol calorimeter at 298.15 K to be △sHm^- [ SmCl3·6H2O （s）, 298.15 K ] = - 103.98 ± 0.04 kJ·mol^-1, △sHm^- [2 C7H6O3 （s）, 298.15 K] = 16.35±0.14 kJ·mol^-1,△sHm^-[C9H7NO （s）, 298.15 K] = -6.11±0.08 kJ·mol^-1 and △sHm^-[Sm（C7H5O3）2·（C9H6NO） （s）, 298.15 K] = - 130.08 ± 0.04 kJ·mol^-1, respectively. The enthalpy was determined to be △rHm^- = 89.59 ±0.18 kJ·mol^-1 for the reaction SmCl3·6H2O（s） ＋ 2C7H6O3（s） ＋ C9H7NO（s） = Sm （C7H5O3） 2·（C9H6NO） （ s ） ＋ 3HCl （g） ＋ 6H2O （ l ）. According to the above results and the data given in literature and through Hess＇ law, the standard molar enthalpy of formation of Sin（ C7H5O3 ）2·（C9H7NO）（s） was estimated to be △rHm^- [ Sm （C7H5O3）2·（C9H6NO） （s）, 298.15 K] = - 2055.9 ± 3.03 kJ·mol^-1.

Polymerization of Phenyl Isocyanate by Divalent Samarium Complex (ArO)_2Sm(THF)_4 (ArO=2,6-di-tert-butyl-4-methylphenoxo)

Phenyl isocyanate was for the first time successfully polymerized by divalent samarium complex (ArO)2Sm(THF)4. The monomer concentration and temperatur affected the polymerization greatly.

Polymerization of Acrylonitrile Initiated by Di（2，6－di－tert－butyl－4－methylphenoxo） Samarium Complex

The polymerization of acrylonitrile initiated by organolanthanide complexes alone is studied for the first time. The effect of polymerization conditions on catalytic activity of the title complex and molecular weight of the polymers produced have been studied.

Non-isothermal kinetics of the first-stage decomposition reaction of the complex of samarium p-methoxybenzoate with 1,10-phenanthroline

The complex of [Sm（p-MOBA）3phen]2 （p-MOBA, p-methoxybenzoate; phen,1 10-phenanthroline） was prepared and characterized by elemental analysis, IR, and UV spectroscopy. The thermal decomposition of the [Sm（p-MOBA）sphen]2 complex and its kinetics were studied under a static air atmosphere by TG-DTG methods. The intermediate and residue for each decomposition stage were identified from the TG curve. The kinetic parameters and mecha- nisms of the first decomposition stage were obtained from the analysis of the TG-DTG curves by a new method of processing the data of thermal analysis kinetics. The lifetime equation at a mass loss of 10% was deduced as lnr= - 30.6795 ＋ 21034.56/Tby isothermal thermogravimelric analysis.

Non-isothermal Decomposition Kinetics of Complexes [Sm(m-MBA)_3phen]_2 and [Sm(o-MOBA)_3phen]_2·2H_2O

In recent years, there has been considerable inte- rest in complexes formed by lanthanide cations and va-rious benzoate derivatives^[1-4], due to their potential application in areas, such as extraction, separation, germicide preparation, catalysis, luminescence, and functional material preparation^[5]. As a continuation of the study on lanthanide carboxylate^[6-13], samarium complexes with m-methylbenzoic acid or o-methoxy- benzoic acid and 1,10-phenanthroline were synthesized and characterized by elemental analysis and IR spec- trometry. The thermal decomposition mechanisms of the two complexes were derived and the corresponding non- isothermal kinetics was studied using the Achar diffe- rential method^[14], the MKN integral method^[15], the non-linear isoconversional integral （ NL-INT）, and dif-ferential（NL-DIF） method^[16,17]. The information of the thermodynamic properties of the complex is impor- tant to characterize and understand the properties of the coordination compound, which could eventually be use-ful in determining their potential application.

Molecular Structure of Bicyclopentadienyl (methycyclopentadienyl) Furanto Samarium

The mixed tris-cyclopentadienyl tetrahydrofuranato samarium complexes bis-(cyclopentadienyl) methylcyclopentadienyl tetrahadrofuranato samarium (Ⅰ) was synthesized by reaction of (C_5H_5)_2SmCl with methyl cyclopentadienyl sodium in THF. [(C_5H_5)_2(C_5H_4CH_3)(C_4H_8O)Sm] (Ⅰ) was characterized by elemental analyses, IR spectra and MS spectra. The structure of [(C_5H_5)_2(C_5H_4CH_3)(C_4H_8O)Sm] (Ⅰ), which has two slightly different independent molecules per asymmetric unit, was elucidated through complete X-ray analysis. The crystals are monoclinic with a=1.2791(3) nm, (b=1.0467(2) nm,) c=2.6108(5) nm, β=98.22(2)°, space group Cc, R=0.0381 for 2103 observed reflection with I3σ(I).

Hydrothermal Synthesis,Crystal Structure and Thermal Properties of a Novel Samarium Complex with 1D Nano-chain Structure

1 Introduction The design and construction of metal-organic polymers has been a field of rapid growth in materials chemistry because of their intriguing topologies and potential applications as functional materials. In this regard, every effort has been devoted to the deliberate design and control of self-assembly infinite coordination networks via selecting the chemistry structures of ligands, Multidentate carboxylate ligands are widely adopted for construction of coordination frameworks due to their rich coordination modes.

CRYSTAL STRUCTURE OF SAMARIUM THIOCYNATE COMPLEX WITH TETRAETHYLENE GLYCOL

The title complex(C_(11)H_(20)N_3O_6S_3Sm)has been crystallized in triclinic space group P with following unit cell constants: a=8.721(O) ,b=10.468(2) ,c=12.346(8) , =86.39(8) β=71.30(7) γ_=66.77(5) V=970.5(1) ~3,Z=2.The final R factor is 0.040.The coordination number of Samarium atom is nine.The tetraethylene glycol acts as a pentadentate ligand and forms a ringlike structure.

Nonisothermal Kinetics of Dehydration Process of [Sm(m-ClBA)_3phen]_2·2H_2O and [Sm(p-ClBA)_3phen]_2·2H_2O

Compounds [Sm（m-CIBA）3phen]2.2H20 and [Sm（p-CIBA）3phen]2·2H20（m-CIBA=m-chlorobenzoate, pClBA=p-chlorobenzoate, phen=l,10-phenanthroline） were prepared. The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics. The Arrhenius equation for the dehydration process can be expressed as lnk=-38.65-243.90×l0^3/RT for [Sm（m-CIBA）3phen]2·2H2O, and lnk=38.70-172.22×103/RT for [Sm（p-CIBA）3phen]2·2H2O. The values of △H^1, △G^1, and △S^1 of dehydration reaction for the title comnonnds are determined respectively.

Luminescent and Thermal Properties of Sm^(3+) Complex with Salicylate and o-Phenanthroline Incorporated in Silica Matrix

A ternary Sm（ Ⅲ ） complex with salicylate （sal-） and o-phenanthroline （phen） was synthesized and incorporated in silica matrix by sol-gel method. The luminescence behavior of the complex in silica gel was studied compared with that of the pure complex by means of emission, excitation spectra and thermogravimetic analysis. The results indicate that the fluorescence intensity ratio of the ^4G5/2→^6H9/2 transition to the ^4G5/2→^6H5/2 transition in silica gel doped with Sm（sal）3 （phen） is lower than that of the pure Sm（sal）3（phen）. The thermal stability of Sm（sal）3（phen） is enhanced greatly by the introduction of the complex into silica matrix. An isolated and chemical inert environment of the complex appears to be responsible for the thermal stability enhancement in silica gel.

Polymerization of N-Phenylmaleimide Catalyzed by (ArO)_2Sm(THF)_4

N phenylmaleimide was successfully polymerized by divalent samarium complex (ArO) 2Sm(THF) 4 (ArO= 2,6 ditertbutyl 4 methyl phenoxo ). The results show that the conversion of polymerization is higher in THF than in other solvents and increases with increasing the monomer concentration. The temperature has less effect on the polymerizing process.

Catalytic Cyclotrimerization of Arylnitriles Using the Novel Samarium(II) Complexes as Catalysts

Samarium(II) complexes or Samarium(II) complexes/n-hexylamine systems were found to be efficient catalysts for cyclotrimerization of arylnitriles. A variety of nitrites can be converted into the corresponding substituted-s-triazines under mild conditions in good to high yields by using samarium (II) complexes/n-hexylamine as catalysts. The same reaction catalyzed by samarium(II) complexes alone gives s-triazines in moderate yields.

Synthesis and Thermal Decomposition Kinetics of the Complex of Samarium p-Methylbenzoate with 1 ,10-Phenanthroline

The complex [Sm（p-MBA）3phen]2 （p-MBA, p-methylbenzoate; phen, 1,10-phenanthroline） was prepared and characterized by elemental analysis, IR and UV spectra. The thermal decomposition process of [Sm（pMBA）3phen]2 was studied under a static air atmosphere by TG-DTG and IR techniques. Thermal decomposition kinetics was investigated employing a newly proposed method, together with the integral isoconversional non-finear method. Meanwhile, the thermodynamic parameters （AH#, △G# and AS#） were also calculated. The lifetime equation at mass-loss of 10% was deduced as In r=-24.7825＋ 18070.43/T by isothermal thermogravimetric analysis.

Synthesis, crystal structure and properties of a samarium nitrate complex with 2-idobenzoic acid and 2,2'-bipyridine

A complex [Sm（2-IBA）2（2,2’-bipy）（NO3）]2 （2-HIBA=2-idobenzoic acid; 2,2’-bipy=2,2’-bipyridine） was synthesized by solvent method and characterized by X-ray single-crystal diffraction. The complex crystallized in triclinic crystal system, Pī space group, with a= 0.97873（3） nm, b=1.28124（3） nm, c=1.29174（3） nm, α=108.3740（10）o, β=111.7340（10）o, γ=101.7870（10）o. The complex was the centrosymmetric binuclear molecule, in which two Sm3＋ ions were connected by four 2-IBA ligands. Two of the 2-IBA ligands were in a bidentate bridging mode and the other two were in a tridentate bridging mode. Sm3＋ ion was also coordinated to one chelating NO3– group and one 2,2’-bipy molecule. The 2D supramolecular network formed through weak I…I interactions and π…π stacking interactions. The fluorescent emission peaks at 562, 595, and 642 nm corresponded to the 4G5/2→6F5/2, 4G5/2→6F7/2, and 4G5/2→6F9/2 transitions of Sm3＋ ion, respectively.

Hydrothermal Synthesis, Crystal Structure and Luminescence Property of a New Binuclear Cage-like Samarium(Ⅲ) Complex Sm2(C7H4ClCOO)6(C(12)H8N2)2(H2O)2

A new binuclear cage-like samarium(Ⅲ) complex Sm2(C7H4ClCOO)6(C(12)H8N2)2(H2O)2(1) with samarium(Ⅲ) nitrate, m-chlorobenzoic acid and 1,10-phenanthroline(phen) was synthesized. It crystallizes in the triclinic space group P1, with a = 8.0217(2), b = 12.9037(4), c = 15.3764(5) ?, α = 85.373(3)o, β = 84.396(3)o, γ = 80.443(3)o, V = 1558.64(8) ?~3, Dc = 1.636 g/cm^3, Z = 2, F(000) = 806, the final GOOF = 1.051, R = 0.0754 and wR = 0.1388. The whole molecule consists of two samarium ions bridged by four m-chlorobenzoic acid anions. The Sm(III) ion is coordinated by eight atoms to give a distorted square antiprism coordination geometry. The TG analysis and fluorescent properties of 1 were studied.

Synthesis, Characterization and Thermodecomposition Kinetics of Sm（Ⅲ） Complex with Unsymmetrical Schiff Base Zwitterion Ligand

A new unsymmetrical Schiff base zwitterion （Ⅲ） was synthesized using L-lysine, salicylaldehyde and 2-hydroxy-l-naphthaldehyde. Samarium（Ⅲ） complex of this ligand [SmL（NO3）]NO3·2H2O has been prepared and characterized by elemental analyses, IR, UV and molar conductance. The thermal decomposition kinetics of the complex for the second stage was studied under non-isothermal condition by TG and DTG methods. The kinetic equation may be expressed as dα/dt=3/2Ae^E/RT（1-α）^2/3[1-（1 -α）^1/3）]^-1. The kinetic parameters （E, A）, activation entropy △S^x and activation free-energy △G^x were also gained.