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1.
《Journal of Coordination Chemistry》2012,65(3):311-313
Abstract Kojic acid or 5-hydroxy-2-(hydroxymethyl)pyran-4-one (I) is an antibiotic substance produced by Aspergilli. It is known to inhibit thegrowth of E. coli and S. aureus.1,2 Since the antibiotic activity of a drug is altered in the presence of metal ions, it was thought worthwhile to synthesise and characterise a few organomercury (11) complexes of kojic acid of the type RHgL(II) [R = C6 H5. o-, p-HOC6H4, p-AcOC6H4, 2-C4H3O (2-furyl); HL = kojic acid] and to study their activity against E. coti and P. pyocyuneu bacterial strains. This is a sequel to our investigation of metal ion-biomolecule interaction.3–6 相似文献
2.
Pyrazole, thiazolidinone, and azetidinone derivatives were synthesized from chalcones of 4-hydroxycoumarin. The structures of all the synthesized compounds were confirmed on the basis of spectral and analytical data. The compounds were screened in vitro for their antibacterial activity against various bacterial strains. 相似文献
3.
S. S. Kandil F. I. Abdel-Hay R. M. Issa 《Journal of Thermal Analysis and Calorimetry》2001,63(1):173-180
The thermal decompositions of cobalt(II), nickel(II) and copper(II) complexes of4-(3'-sulfonylazido-6'-methoxyphenylazo)-1-phenyl-3-methyl-2-pyrazolin-5-one H(D1–SO2N3) and 4-(4'-sulfonylazido phenylazo)-3-phenyl-3-methyl-2-pyrazolin-5-one H(D2–SO2N3) were studied by thermogravimetry. The decomposition in all cases takes place along two stages. The first stage is due to the elimination of water and nitrogen molecules with the formation of tetracoordinate complexes containing nitrene reactive species[M(DSO2N:)2]. The second stage represents the decomposition of the material to the metal oxide. The kinetics of the decomposition were examined by using Coats–Redfern, the decomposition in all complexes was found to be first order for the first and second stages. The activation energies and other activation parameters (H* and S* and G*) were computed and related to the bonding and stereochemistry of the complexes.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
4.
Trikha A. K. Kaur Shivjinder Sodhi G. S. 《Journal of Thermal Analysis and Calorimetry》2000,61(1):151-156
The new mixed ligand complexes with the formulae Zn(2-bipy)(ox), Zn(4-bipy)1.5 (ox)H2 O, Zn(2,4'-bipy)2 (ox)2H2 O, Cd(2-bipy)(ox)2H2 O, Cd(4-bipy)2 (ox) and Cd(2,4'-bipy)(ox)2H2 O (2-bipy, 4-bipy, 2,4'-bipy=2,2'-, 4,4'- and 2,4'bipyridine, ox=oxalate) were prepared. The thermal decompositions of these
compounds were studied by means of TG, DTG and DTA in air. During heating the complexes decompose via different intermediate
products to ZnO and CdO. The Zn(II) complexes are thermally more stable than the corresponding Cd(II) complexes. The influence
of nitrogen atom position in the bipyridine isomers and nature of central atom on the thermal behaviour of these complexes
was discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Patrinoiu G. Patron L. Carp O. Stanica N. 《Journal of Thermal Analysis and Calorimetry》2003,72(2):489-495
Two iron(III) complexes with therapeutically active biguanides - N',N'-anhydrobis-(beta-oxyethyl) biguanide (HMBig), and N',N'-dimethylbiguanide
(HMetf), respectively - [Fe(HMBig)3]Cl3·9H2O (I) and [Fe(HMBig)(HMetf)]Cl3·6H2O (II) - were synthesized and characterized through elemental analysis, electrical conductivity, IR and UV/VIS spectroscopy, measurements
in magnetic field and non-isothermal analysis. In studied complexes the biguanide derivatives act as bidentate ligands through
nitrogen atoms of the iminic groups. Their magnetic moments correspond to iron(III) in the spin quartet ground state. The thermal analysis evidenced an endotherm release of crystallization and coordinated
water molecules. The degradation of the ligand molecules is a complex one, several processes being overlapped. The presence
of biguanidic ligand increase the thermal stability of the coordination compound. The final product of both thermal decompositions
is a-Fe2O3.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
N. Ózpozan H. Arslan T. Ózpozan M. Merdivan N. Külcü 《Journal of Thermal Analysis and Calorimetry》2000,61(3):955-965
Thermogravimetry (TG) and differential thermal analysis (DTA) were performed on the complexes with general formula (M(DEBT)n (where M =Fe, Co, Ni, Cu or Ru; n =2, or 3 and DEBT=N,N-diethyl-N'-benzoylthiourea). Derivative thermogravimetric (DTG) curves were also recorded in order
to obtain decomposition data on the complexes. The complexes of Fe(III), Co(II), Ni(II), Cu(II) and Ru(III) displayed two-
or three-stage decomposition patterns when heated in a dynamic nitrogen atmosphere. Mass loss considerations relating to the
decomposition stages indicated the conversion of the complexes to the sulfides or to the corresponding metal alone (Cu, Ru,
NiS, CoS or FeS). Mathematical analysis of the TG and DTG data showed that the order of reaction varied between 0.395 and
0.973. Kinetic parameters such as the decomposition energy, the entropy of activation and the pre-exponential factor are reported.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
2,4'-Bipyridyl (2,4'-bipy or L) complexes of Mn(II) with the formulae MnL2X2·2H2O (X–=Cl, Br, NCS, NO3), MnLSO4·5H2O and MnL4(ClO4)2·2H2O were synthesized and characterized via the IR spectra and magnetic, and conductivity measurements. The nature of the Mn(II)-ligand coordination is discussed. The thermal decompositions of these compounds were studied in air atmosphere. The mode of decomposition depends on the anion present, but the final product in all cases is Mn3O4. Some of the intermediates (MnL2Cl2, MnLCl2, MnL2Br2, MnL2(NCS)2 and MnLSO4) formed during the pyrolysis are isomeric with 2,2'-bipy and 4,4'-bipy complexes.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
8.
M. Sikorska-Iwan R. Mrozek Z. Rzączyńska 《Journal of Thermal Analysis and Calorimetry》2000,60(1):139-144
The thermal decomposition reactions of manganese(II) complexes with L-proline and 4-hydroxy- L-proline were studied. The Mn(II) proline complex loses the water molecule at 40–95°C and then, heated above 250°C it decomposes
in several steps to manganese oxide. The most appropriate kinetic equations for dehydration process are the geometrical R2
or R3 ones. They give a value of activation energy, E of about 95 kJmol–1. The Mn(II) hydroxyproline complex loses the water molecules in two stages (70–110 and 110–230°C) and next it decomposes
to manganese oxide in several steps. The R3 or D3 (three-dimensional diffusion) models are the most appropriate for the first
stage of dehydration (E is about 155 kJ mol–1). The second step of dehydration is limited by D3 mechanism (E=52 kJ mol–1).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Copper(II), zinc(II) and cadmium(II) complexes of the Schiff base, fluorenone anthranilic acid were prepared and characterized by elemental analysis, magnetic measurements, conductivity experiments and electronic and infrared spectral studies. The thermal decomposition kinetics and mechanism of these chelates was studied from TG data. 相似文献
10.
Cobalt(II), nickel(II), copper(II) and zinc(II) complexes of two new Schiff-bases, citronellal anthranilic acid and citronellal-5-bromoanthranilic
acid have been synthesized. On the basis of spectral, magnetic and thermal data, octahedral structure was assigned to all
complexes [ML2(H2O)2]. Thermal decomposition of these complexes was studied by TG. Kinetic parameters, viz activation energy, E, pre-exponential
factor, A, and order of reaction, n, were calculated from the TG curves using mechanistic and non-mechanistic integral equations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
12.
S. V. Fokin G. V. Romanenko M. Baumgarten V. I. Ovcharenko 《Journal of Structural Chemistry》2003,44(5):864-869
The organomercury biradical HgL2 (L is deprotonated 4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl) is capable of performing the bridging function for design of multinuclear heterospin systems. This paper describes synthesis and crystal structure of HgL2 and the first multinuclear complexes of Cu(hfac)2 with HgL2. 相似文献
13.
14.
Maji T. K. Das D. Sain S. Ray Chaudhuri N. 《Journal of Thermal Analysis and Calorimetry》2002,68(1):319-328
CuL2C4O4 [L=ethane-1,2-diamine (en)], CuL2C4O4⋅2H2O [L=N-methylethane-1,2-diamine (meen), N-ethylethane-1,2-diamine (eten),N-propylethane-1,2-diamine (pren), N-methyl-N’-ethylethane-
1,2-diamine (meeten) andpropane-1,2-diamine (pn)], CuL2C4O4⋅0.5H2O [L=N,N’-dimethylethane- 1,2-diamine (dmeen)], CuL2C4O4⋅4H2O [L=propane-1,2-diamine (pn)]and CuL2C4O4⋅H2O[L=2-methylpropane-1,2-diamine (ibn)] have been synthesized by the addition of respective diamine to finely powdered CuC4O4⋅2H2O and their thermal studies have been carried out in the solid state. Cu(en)2C4O4 upon heating loses one molecule of diamine with shar pcolour change yielding Cu(en)C4O4 which upon further heating transforms to unidentified products. All aquated-bis-diamine species [CuL2C4O4⋅2H2O, CuL2C4O4⋅0.5H2O and CuL2C4O4⋅H2O] upon heating undergo deaquation–anation reaction in the solid state showing thermochromism and transform to CuL2C4O4, which revert on exposure to humid atmosphere (RH ∼90%). All the squarato bis-diamine species, CuL2C4O4, on further heating transform to unidentified products through the formation of CuLC4O4 as intermediates. The mono diamine species, have been isolated pyrolytically in the solid state and can be stored in a desiccator
as well as in open atmosphere. They are proposed to be polymeric.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
[NiL3]X2 (where L=N-phenylethane-1,2-diamine and X=I− and ClO4
−), [NiL2X2] (X is Cl−, Br−, NCS−, 0.5SO4
2− or 0.5SeO4
2−) and [NiL2(H2O)2](NO3)2 have been synthesized from solution and their thermal study has been carried out in the solid phase. [NiL2Cl2] upon heating undergoes irreversible endothermic phase transition (142–152°C, ΔH=0.35 kJ mol−1) without showing any visual colour change. This phase transition is assumed to be due to conformation changes of the diamine
chelate rings. NiLCl2 and NiL2.5I2 have been prepared pyrolytically from [NiL2Cl2] and [NiL3]I2 respectively in the solid state. [NiL2(H2O)2](NO3)2 upon heating undergoes deaquation-anation reaction without showing any visual colour change. [NiL2X2] (X is Cl−, Br−, NCS−), [NiL2(H2O)2](NO3)2 and [NiL2(NO3)2] possess trans-octahedral configuration, whereas, [NiL2X2] (X is 0.5SO4
2− or 0.5SeO4
2−) are having cis-octahedral configuration. Amongst the complexes, only NiLCl2 shows unusually high (5.1 BM at 27°C) magnetic susceptibility value.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Zupančič M. Cerc Korošec R. Bukovec P. 《Journal of Thermal Analysis and Calorimetry》2001,65(3):787-795
The thermal behaviour of Mg(II), Zn(II) and Co(II) compounds of ciprofloxacin was studied by thermogravimetry (TG) and differential
thermal analysis (DTA) in order to determine or to confirm some structural characteristics of substances. The complexes decompose
in two steps: dehydration and pyrolytic decomposition of the anhydrous complexes to form metal oxide or metal fluoride. The
dehydration process of one magnesium(II) compound takes place in two steps suggesting a marked difference in the bonding of
water molecules. The different bonding mode of the ciprofloxacin molecules in both magnesium compounds leads to different
residues of the thermal decompositions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
Mahmoud Khodari 《Mikrochimica acta》1999,131(3-4):231-235
The stability constants for the binary M(II)- chlorpromazine hydrochloride (CPZ) and the ternary complexes M(II)-chlorpromazine-amino
acid, have been studied using pH-measurements. The amino acids (aa) are: glycine, glutamic acid, histidine and the metal ions
are: Cu(II), Zn(II), Co(II), Ni(II) and UO2(II). All experiments were carried out in the presence of 0.1 mol dm−3 KNO3. The resulting stability constants of the binary and the ternary complexes were compared. It was observed that the stability
of the ternary complexes-except for glutamic acid – are lower than of the binary ones.
Received October 22, 1998. Revision March 14, 1999. 相似文献
18.
S. H. Tarulli O. V. Quinzani J. Dristas E. J. Baran 《Journal of Thermal Analysis and Calorimetry》2000,60(2):505-515
Complexes of Cu(II) with substituted o-acetoxy benzoic acids (5-haloaspirines, X-asp) with and without pyridine (py), of composition
[Cu2(X-asp)4] and [Cu(X-asp)2(py)2 ] have been synthesized and characterized. Electronic and vibrational spectroscopic data of these complexes are reported.
Its thermal behaviour was investigated by thermogravimetry and differential thermal analysis. In all complexes, the haloaspirinate
ligands decompose in two or three steps, starting with the break up of the coordinated acetoxy groups. CuO is obtained as
the final pyrolysis residue in all cases.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
Mrozek R. Rzączyńska Z. Sikorska-Iwan M. 《Journal of Thermal Analysis and Calorimetry》2001,63(3):839-846
The thermal decomposition behaviour of the manganese(II) complexes with glycine: Mn(gly)Cl2(H2O)2, Mn(gly)2Cl2, Mn(gly)Br2(H2O)2, Mn(gly)2Br2(H2O)2 was investigated by means of TG-DTG-DTA, Hi-Res-TA and DSC techniques. The evolved gas analysis was carried out by means
of the coupled TG-FTIR system. Heating of the complexes results first in the release of water molecules. Next, the multi-stage
decomposition process with degradation of glycine ligand occurs. Water, carbon dioxide and ammonia were detected in the gaseous
products of the complexes decomposition. The temperature of NH3 evolution from the complexes is higher than from free glycine. The final residue in the air atmosphere is Mn2O3 which transforms into Mn3O4 at 930°C. In a nitrogen atmosphere, the complexes decompose into MnO.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
The thermal decomposition of the complexes Mg(Clac)2 (ron)2 ×3H2 O(I), Mg(Cl2 ac)2 (ron)2 ×3H2 O(II) and Mg(Cl3 ac)2 (ron)2 ×3H2 O(III), where Clac =ClCH2 COO- , Cl
2
ac =Cl2 CHCOO- , Cl
3
ac =Cl3 CCOO- and ron =3-pyridylcarbinol (ronicol) had been investigated in air atmosphere in temperature range 20–1000°C by means of TG and DTA.
The composition of the complexes and the solid state intermediate and resultant products of thermolysis had been identified
by means of elemental analysis and complexometric titration. The possible scheme of destruction of the complexes is suggested.
The final product of the thermal decomposition was MgO. The thermal stability of the complexes can be ordered in the sequence:
I<III<II. IR data suggest that ronicol was coordinated to Mg(II) through the nitrogen atom of its heterocyclic ring.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献