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1.
Shu-Jing Sun Juan-Fen Wang Ning Ren Jian-Jun Zhang Hong-Mei Ye Shu-Ping Wang 《Structural chemistry》2012,23(1):79-89
Some binuclear lanthanide complexes with the general formula [Ln(2,3-DClBA)3bipy]2 (Ln = Sm(1), Eu(2), Tb(3), Dy(4), and Ho(5); 2,3-DClBA = 2,3-dichlorobenzoate; bipy = 2,2′-bipyridine) were synthesized and characterized by elemental analysis, molar
conductance, infrared, ultraviolet, luminescent spectroscopy, thermogravimetry, and different thermogravimetry (TG–DTG) techniques.
The single crystals of the complexes have been obtained except the complex 2 and their structures have been determined by single-crystal X-ray diffraction. The four complexes are isostructural and the
rare earth ions are all nine coordinated. The two rare earth ions in each complex are linked by two bridging bidentate and
two chelating-bridging tridentate carboxylate groups. Under ultraviolet light excitation, the europium and terbium complexes
exhibited characteristic red fluorescence of Eu3+ ion and green fluorescence of Tb3+ ion at room temperature. The non-isothermal kinetics was investigated by using the integral isoconversional non-linear (NL-INT)
and the Popescu methods. The mechanism functions of the first decomposition step of the complexes 3–5 were determined. Meanwhile, the thermodynamic parameters (ΔG
≠
, ΔH
≠, and ΔS
≠) at DTG peak temperatures were also calculated. 相似文献
2.
L. Tian N. Ren J. J. Zhang H. M. Liu S. J. Sun H. M. Ye K. Z. Wu 《Journal of Thermal Analysis and Calorimetry》2010,99(1):349-356
The two complexes of [Ln(CA)3bipy]2 (Ln = Tb and Dy; CA = cinnamate; bipy = 2,2′-bipyridine) were prepared and characterized by elemental analysis, infrared
spectra, ultraviolet spectra, thermogravimetry and differential thermogravimetry techniques. The thermal decomposition behaviors
of the two complexes under a static air atmosphere can be discussed by thermogravimetry and differential thermogravimetry
and infrared spectra techniques. The non-isothermal kinetics was investigated by using a double equal-double steps method,
the nonlinear integral isoconversional method and the Starink method. The mechanism functions of the first decomposition step
of the two complexes were determined. The thermodynamic parameters (ΔH
≠
, ΔG
≠
and ΔS
≠
) and kinetic parameters (activation energy E and the pre-exponential factor A) of the two complexes were also calculated. 相似文献
3.
Shu-Jian Chen Julia K. C. Abbott Carlos A. Steren Zi-Ling Xue 《Journal of Cluster Science》2010,21(3):325-337
Metal cage complexes [(Me2N)3MO]4 (M = Nb, 3; Ta, 4) have been prepared from the reactions of M(NMe2)5 (M = Nb, 1; Ta, 2) with water. Single crystal X-ray diffraction studies of 3 and 4 reveal that they adopt cubane-like structures with M–O bridges. Variable-temperature NMR studies of –NMeAMeB rotations in 3 and 4 have been performed to give the following activation parameters for the exchanges: ΔH
≠ = −1.4(1.1) kJ/mol, ΔS
≠ = −209(8) J/mol K,
\Updelta G 30 8 \textK 1 = 6 4( 2) \textkJ/\textmol \Updelta G_{{_{{ 30 8\;{\text{K}}}} }}^{{^{ \ne } }} = 6 4\left( 2\right)\;{\text{kJ}}/{\text{mol}} for 3, and ΔH
≠ = −0.9(1.2) kJ/mol, ΔS
≠ = −2.1(0.2) × 102 J/mol K,
\Updelta G 30 8 \textK 1 = 6 3( 6) \textkJ/\textmol \Updelta G_{{ 30 8\;{\text{K}}}}^{{^{ \ne } }} = 6 3\left( 6\right)\;{\text{kJ}}/{\text{mol}} for 4. 相似文献
4.
水热法合成了2个镧系配合物[Ln(3,4-DFBA)3(phen)(H2O)]2(H2O)2(Ln=Sm (1),Ho (2);3,4-DFBA=3,4-二氟苯甲酸, phen=菲咯啉)。利用X-射线单晶衍射仪测定了配合物的晶体结构。配合物1和2结构相同,配位数为8,属于三斜晶系,空间群为P1。相邻的2个双核分子之间通过分子间氢键作用形成了2D层状结构。并用元素分析,红外,紫外,XRD等手段对目标配合物进行了表征。用TG-DTG技术测定了配合物的热稳定性,同时对配合物1的荧光性能进行了研究。另外,还测定了这两种配合物对白色念珠菌,革兰氏阳性菌(大肠杆菌)以及革兰氏阴性菌(金黄色葡萄球菌)的抑菌活性。 相似文献
5.
Zheyu Zhang 《Journal of Cluster Science》2011,22(4):705-714
Three novel 1:2 composite compounds prepared with the isopolyanions and lanthanide-organic units, (NH4)2{[Ln2(HL)2(H2O)9][(H2W12O40)]}·nH2O (Ln = Gd3+ (1), Tb3+ (2), n = 15; Ho3+ (3), n = 10; L = pyridine-3,5-dicarboxylate) were synthesized at room temperature and characterized by routine methods. X-ray structural
analysis reveals that these structures are isomorphic: two crystallographically independent Ln3+ ions (Ln1 and Ln2) locate in different coordination environments; two ligands plays dissimilar coordination mode; the isopolyanion
cluster acts as a tridentate ligand and connects three Ln3+ ions (Ln1, Ln1′ and Ln2) forming an unusual 2D undee-layer. The room temperature luminescent of 2 has been studied and exhibits a Tb3+ characteristic emission in the range of 450–650 nm. 相似文献
6.
水热法合成了2个镧系配合物[Ln(3,4-DFBA)3(phen)(H2O)]2(H2O)2(Ln=Sm (1), Ho (2);3, 4-DFBa=3, 4-二氟苯甲酸根, phen=菲咯啉)。利用X-射线单晶衍射仪测定了配合物的晶体结构。配合物1和2结构相同, 配位数为8, 属于三斜晶系, 空间群为P1。相邻的2个双核分子之间通过分子间相互作用力形成了2D层状结构。并用元素分析, 红外, 紫外, XRD等手段对目标配合物进行了表征。用TG-DTG技术测定了配合物的热稳定性, 同时对配合物1的荧光性能进行了研究。另外, 还测定了这两种配合物对白色念珠菌, 革兰氏阴性菌(大肠杆菌)以及革兰氏阳性菌(金黄色葡萄球菌)的抑菌活性。 相似文献
7.
The stability of the singlet dicyclopropylcarbene (ΔE
S–T = 15.3 kcal/mol, 1) is increased not only by cyclization to 2,5-dicyclopropylcyclopentanylidene (ΔE
S–T = 20.3 kcal/mol, 2), but even more so by unsaturation to 2,5-dicyclopropylcyclopentenylidene (ΔE
S–T = 22.5 kcal/mol, 3). In a further attempt to pave the way toward synthesis of new stable dialkylcarbenes, we introduced different substituents
on the α-cyclopropyls of 3, where the stability was increased over twice of 1 (ΔE
S–T = 37.8 kcal/mol) for 2,5-bis(2,3-dihydroxycyclopropyl)-3,4-dinitrocyclopentenylidene,
3\textOH-\textNO 2 {\mathbf{3}}_{{{\text{OH}}{-}{\text{NO}}_{ 2}}} . 相似文献
8.
Thathan Premkumar Subbiah Govindarajan 《Journal of Thermal Analysis and Calorimetry》2010,100(2):725-732
The new hydrazinium lanthanide metal complexes of 2-pyrazinecarboxylic acid (HpyzCOO) of the formulae (N2H5)2[Ln(pyzCOO)5] · 2H2O (1), where Ln = La or Ce and (N2H5)3[Ln(pyzCOO)4(H2O)] · 2NO3 (2), where Ln = Pr, Nd, Sm or Dy have been synthesized and characterized by physico-chemical methods. The IR absorption bands
of N–N stretching at 960 cm−1 unambiguously prove the existence of N2H5
+ ions. The bonding parameters β, b1/2, % δ and η, have been calculated from the electronic spectroscopic (hypersensitive) bands of Pr(III) and Nd(III) complexes.
All the complexes undergo endothermic followed by exothermic decomposition to leave the respective metal oxides as the end
products. However, the DTA of the complexes 2 demonstrate rather sharp peak than the complexes 1, owing to overwhelming exothermicity, which may be due to the loss of both hydrazine and nitrate moieties in the same step.
The X-ray powder diffraction studies reveal the existence of isomorphism among the member complexes. 相似文献
9.
Abstract
A series of 1-D lanthanide coordination polymers [Ln(μ3-OH)(pybz)(pa)] n (Ln = Er (1), Tb (2), Gd (3), Hpybz = 4-pyridin-4-yl-benzoic acid, Hpa = 2-picolinic acid) based on [Ln4(μ3-OH)4] cluster units have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, IR, elemental analysis, and thermogravimetric analysis. X-ray crystal structure analyses reveal that 1–3 are isomorphous with tetragonal space group P [`4] \overline{4} 21c and comprise tetranuclear Ln–O clusters, in which four Ln3+ centers are joined together by four μ3-bridging hydroxyl groups to form cubane-like [Ln4(μ3-OH)4]8+ cores that are further linked by four μ3-pa− ligands to produce 1-D chains along the c-axis. 相似文献10.
H. M. Ye N. Ren H. Li J. J. Zhang S. J. Sun L. Tian 《Journal of Thermal Analysis and Calorimetry》2010,101(1):205-211
The complex of [Nd(BA)3bipy]2 (BA = benzoic acid; bipy = 2,2′-bipyridine) has been synthesized and characterized by elemental analysis, IR spectra, single
crystal X-ray diffraction, and TG/DTG techniques. The crystal is monoclinic with space group P2(1)/n. The two–eight coordinated Nd3+ ions are linked together by four bridged BA ligands and each Nd3+ ion is further bonded to one chelated bidentate BA ligand and one 2,2′-bipyridine molecule. The thermal decomposition process
of the title complex was discussed by TG/DTG and IR techniques. The non-isothermal kinetics was investigated by using double
equal-double step method. The kinetic equation for the first stage can be expressed as dα/dt = A exp(−E/RT)(1 − α). The thermodynamic parameters (ΔH
≠, ΔG
≠, and ΔS
≠) and kinetic parameters (activation energy E and pre-exponential factor A) were also calculated. 相似文献
11.
S. P. Chen X. X. Meng Q. Shuai B. J. Jiao S. L. Gao Q. Z. Shi 《Journal of Thermal Analysis and Calorimetry》2006,86(3):767-774
A
solid complex Eu(C5H8NS2)3(C12H8N2) has been obtained from reaction of
hydrous europium chloride with ammonium pyrrolidinedithiocarbamate (APDC)
and 1,10-phenanthroline (o-phen⋅H2O)
in absolute ethanol. IR spectrum of the complex indicated that Eu3+
in the complex coordinated with sulfur atoms from the APDC and nitrogen atoms
from the o-phen. TG-DTG investigation provided
the evidence that the title complex was decomposed into EuS.
The
enthalpy change of the reaction of formation of the complex in ethanol, Δr
H
m
θ(l), as –22.214±0.081 kJ mol–1,
and the molar heat capacity of the complex, c
m,
as 61.676±0.651 J mol–1 K–1,
at 298.15 K were determined by an RD-496 III type microcalorimeter. The enthalpy
change of the reaction of formation of the complex in solid, Δr
H
m
θ(s), was calculated as 54.527±0.314 kJ mol–1
through a thermochemistry cycle. Based on the thermodynamics and kinetics
on the reaction of formation of the complex in ethanol at different temperatures,
fundamental parameters, including the activation enthalpy (ΔH
≠
θ),
the activation entropy (ΔS
≠
θ),
the activation free energy (ΔG
≠
θ),
the apparent reaction rate constant (k),
the apparent activation energy (E), the
pre-exponential constant (A) and the reaction
order (n), were obtained. The constant-volume
combustion energy of the complex, Δc
U,
was determined as –16937.88±9.79 kJ mol–1
by an RBC-II type rotating-bomb calorimeter at 298.15 K. Its standard enthalpy
of combustion, Δc
H
m
θ,
and standard enthalpy of formation, Δf
H
m
θ,
were calculated to be –16953.37±9.79 and –1708.23±10.69
kJ mol–1, respectively. 相似文献
12.
W. S. Lopes Crislene R. S. Morais A. G. Souza V. D. Leite B. D. de A. Firmo 《Journal of Thermal Analysis and Calorimetry》2007,87(3):841-845
Isothermal
decomposition kinetic of three lanthanide mixed complexes with the general
formula of Ln(thd)3phen (where Ln=Nd3+,
Sm3+ or Er3+, thd=2,2,6,6-tetramethyl-3,5-heptanodione and phen=1,10-phenanthroline) has been studied in this
work. The powders were characterized by their melting point, elemental analysis,
FTIR spectroscopy and thermogravimetry. The isothermal TG curves have been
recorded under the same conditions at 265–285, 265–285 and 250–270°C
for Nd(thd)3phen, Sm(thd)3phen
and Er(thd)3phen, respectively.
The kinetic
parameters, i.e. activation energy, reaction order and frequency factor were
obtained through the technique of lineal regression using the relation g(α)=kt+g
0. The analysis was done
at decomposed fractions between 0.10–0.90. The values of activation
energy were: 114.10, 114.24 and 115.04 kJ mol–1
for the Nd(thd)3phen, Sm(thd)3phen
and Er(thd)3phen complexes, respectively. The kinetic
models that best described the isothermal decomposition reaction the complexes
were R1 and R2. The values of activation energy suggests the following decreasing
order of stability: Nd(thd)3phen<Sm(thd)3phen<Er(thd)3phen. 相似文献
13.
Pagonda Haribabu Yogesh Prakash Patil Katreddi Hussain Reddy Munirathinam Nethaji 《Transition Metal Chemistry》2011,36(8):867-874
The mononuclear Cu(II) complex [Cu(phen)(H2O)(NO3)2] (1), obtained by the reaction of 1,10-phenanthroline with Cu(NO3)2·3H2O in methanol solution, reacts with anionic ligands SCN−, AcO−, N3
− and PhCO2
− in MeOH solution to form the stable binuclear complexes [Cu2(H2O)2(phen)2(μ-X)2]2 (NO3)2, where X = SCN− (2), AcO− (3), N3
− (4) or PhCO2
−(5). The molecular structure of complex 3 was determined by single-crystal X-ray diffraction studies. These complexes were characterized by electronic, IR, ESR, magnetic
moments and conductivity measurements. The electrochemical behaviour of the complexes was investigated by cyclic voltammetry.
The interactions of these complexes with calf thymus DNA have been investigated using absorption spectrophotometry. Their
DNA cleavage activity was studied on double-stranded pBR322 plasmid DNA using gel electrophoresis experiments in the absence
and presence of H2O2 as oxidant. 相似文献
14.
Francisco C. C. Arantes Antonio C. Moro Iolanda S. Klein Cristiana da Silva Adelino V. G. Netto Antonio E. Mauro Vânia M. Nogueira 《Journal of Thermal Analysis and Calorimetry》2011,106(2):379-383
The synthesis, spectroscopic characterization, and thermal analysis of the compounds [Pd(X)2(mtu)(PPh3)] (X = Cl− (1), SCN− (2); mtu = N-methylthiourea; PPh3 = triphenylphosphine) and [Pd(X)2(phtu)(PPh3)] (X = Cl− (3), SCN− (4); phtu = N-phenylthiourea) are described. The thermal decomposition of the compounds occurs in two, three, or four stages and the final
decomposition products were identified as Pd0 by X-ray powder diffraction. The thermal stability order of the complexes is 4 > 3>2 > 1. 相似文献
15.
《Journal of Coordination Chemistry》2012,65(3):424-430
Four 2-D coordination polymers Ln2(phen)2(C5H6O4)3 [Ln?=?Pr(1), Eu(2), Er(3), Yb(4), phen?=?1,10-phenanthroline] were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data reveal that these complexes are isostructural. In the asymmetric unit, the two Ln(III) ions are nine-coordinate and have similar coordination environments. The Ln(III) ions are built into 2-D layers by three different coordination modes of glutarate. The resulting 2-D layer forms 3-D supramolecular architecture by two types of π···π stacking interactions. All the complexes were characterized by IR spectra and thermogravimetric analysis, and the emission spectrum shows that Eu2(phen)2(C5H6O4)3 possesses strong luminescence. 相似文献
16.
Li Xu Yang-Yin Xie Nan-Jing Zhong Zhen-Hua Liang Juan He Hong-Liang Huang Yun-Jun Liu 《Transition Metal Chemistry》2012,37(2):197-205
Two ruthenium(II) polypyridyl complexes, namely [Ru(phen)2(DMDPPZ)](ClO4)2
1 (phen = 1,10-phenanthroline, DMDPPZ = 3,6-dimethyldipyrido[3,2-a:2′,3′-c]phenazine) and [Ru(dmp)2(DMDPPZ)](ClO4)2
2 (dmp = 2,9-dimethyl-1,10-phenanthroline), have been synthesized and characterized. The DNA-binding properties of the complexes
were investigated by spectrophotometric methods, viscosity measurements, and photoactivated cleavage studies. The DNA-binding
constants for complexes 1 and 2 have been determined as 8.78 (±0.94) × 105 M−1 (s = 3.02) and 1.26 (±0.35) × 105 M−1 (s = 1.69), respectively. The results suggest that these complexes bind to calf thymus DNA through intercalation. When irradiated
at 365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than complex 2 under comparable experimental conditions. The cytotoxicities of complexes 1 and 2 have been evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. Complex 2 shows higher anticancer potency than complex 1 against four tumor cell lines. The apoptosis-inducing activity was assessed by acridine orange/ethidium bromide staining
assay, and the antioxidant activities of these complexes against hydroxyl radical were also explored. 相似文献
17.
Zhi-Hong Ma Ming-Xia Zhao Fang Li Hong Wang Xue-Zhong Zheng Jin Lin 《Transition Metal Chemistry》2010,35(4):387-391
Cyclopentadienes (C5Me4R) [R = Allyl (1), n-Butyl (2), Benzyl (3), and PhMe-2 (4)] reacted with Fe(CO)5 in refluxing xylene to give new substituted tetramethylcyclopentadienyl dinuclear iron carbonyl complexes [(η
5-C5Me4R)Fe(CO)(μ-CO)]2 [R = Allyl (5), n-Butyl (6), Benzyl (7), and PhMe-2 (8)], respectively. The four new complexes 5–8 were characterized by elemental analysis, IR, and 1H NMR spectra. The crystal structures of complexes 5–7 were determined using single crystal X-ray diffraction. The crystal structure of complex 5 showed that allyl underwent isomerization to give the corresponding methyl-vinyl. A possible mechanism is discussed. The
X-ray crystal structures of complexes 5, 6, and 7 confirm the structure with bridging and terminal CO groups. They show that the steric effects of substituents influence the
Fe–Fe bond distances of the complexes. 相似文献
18.
Liang Xue Feng-Qi Zhao Xiao-Ling Xing Zhi-Ming Zhou Kai Wang Hong-Xu Gao Jian-Hua Yi Rong-Zu Hu 《Journal of Thermal Analysis and Calorimetry》2010,102(3):989-992
The thermal decomposition behavior of 3,4,5-triamino-1,2,4-triazole dinitramide was measured using a C-500 type Calvet microcalorimeter
at four different temperatures under atmospheric pressure. The apparent activation energy and pre-exponential factor of the
exothermic decomposition reaction are 165.57 kJ mol−1 and 1018.04 s−1, respectively. The critical temperature of thermal explosion is 431.71 K. The entropy of activation (ΔS
≠), enthalpy of activation (ΔH
≠), and free energy of activation (ΔG
≠) are 97.19 J mol−1 K−1, 161.90 kJ mol−1, and 118.98 kJ mol−1, respectively. The self-accelerating decomposition temperature (T
SADT) is 422.28 K. The specific heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide was determined with a micro-DSC method
and a theoretical calculation method. Specific heat capacity (J g−1 K−1) equation is C
p = 0.252 + 3.131 × 10−3
T (283.1 K < T < 353.2 K). The molar heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide is 264.52 J mol−1 K−1 at 298.15 K. The adiabatic time-to-explosion of 3,4,5-triamino-1,2,4-triazole dinitramide is calculated to be a certain value
between 123.36 and 128.56 s. 相似文献
19.
Sahra C. Lemos Silmar J. S. Franchi Adelino V. G. Netto Antonio E. Mauro Oswaldo Treu-Filho Regina C. G. Frem Eduardo Tonon de Almeida Cláudia Torres 《Journal of Thermal Analysis and Calorimetry》2011,106(2):391-397
This work describes the synthesis, characterization, and the thermal behavior investigation of four palladium(II) complexes
with general formulae [PdX2(mba)2], in which mba = N-methylbenzylamine and X = OAc− (1), Cl− (2), Br− (3) or I− (4). The complexes were characterized by elemental analysis, infrared vibrational spectroscopy, and 1H nuclear magnetic resonance. The stoichiometry of the complexes was established by means of elemental analysis and thermogravimetry
(TG). TG/DTA curves showed that the thermodecomposition of the four complexes occurred in 3–4 steps, leading to metallic palladium
as final residue. The palladium content found in all curves was in agreement with the mass percentages calculated for the
complexes. The following thermal stability sequence was found: 3 > 2 > 4 > 1. The geometry optimization of 1, 2, 3, and 4, calculated using the DFT/B3LYP method, yielded a slightly distorted square planar environment around the Pd(II) ion made
by two anionic groups and two nitrogen atoms from the mba ligand (N1 and N2), in a trans-relationship. 相似文献
20.
The complexes
of general formula Ln(btfa)3L, where Ln=Eu
or Tb, btfa=4,4,4-trifluoro-1-phenyl-1,3-butanedione, L=1,10-phenanthroline (phen)
or 2,2-bipyridine (bipy), were synthesized
by reacting the corresponding metal chloride with the proper β-diketone
and the other ligand. The complexes were obtained in the powder form and were
characterized by photoluminescence and TG. Their thermal decomposition was
studied by non-isothermal thermogravimetric techniques. The Eu(btfa)3bipy
complex presented the highest thermal stability and it melts before being
decomposed. The complex Eu(btfa)3phen presented the
largest activation energy for a heating rate of 5°C min–1. 相似文献