Authors:Xiaoyi Li, Yiqun Wu, Donghong Gu, and Fuxi Gan
Four novel metal(II) complexes, Ni(L)2, Co(L)2, Cu(L)2, and Zn(L)2 (L = 5-(2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono)-1,3-diethyl-2-thioxo-dihydropyrimidine-4,6(1H,5H)-dione),
were synthesized using the procedure of diazotization, coupling and metallization. Their structures were identified by elemental
analyses, 1H NMR, ESI-MS and FT-IR spectra. The effect of different central metal(II) ions on absorption bands of the metal(II) complexes
was researched. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential
scanning calorimetry (DSC). Furthermore, the thermodynamic parameters, such as activation energy (E*), enthalpy (∆H*), entropy (∆S*) and free energy of the decomposition (∆G*) are calculated from the TG curves applying Coats–Redfern method. The results show that the metal(II) complexes have suitable
electronic absorption spectra with blue-violet light absorption at about 350–450 nm, high thermal stability with sharp thermal
Authors:D. Czakis-Sulikowska, A. Czylkowska, J. Radwańska-Doczekalska, R. Grodzki, and E. Wojciechowska
New mixed-ligands complexes with empirical formulae: M(2,4′-bpy)2L2�H2O (M(II)Zn, Cd), Zn(2-bpy)3L2�4H2O, Cd(2-bpy)2L2�3H2O, M(phen)L2�2H2O (where M(II)=Mn, Ni, Zn, Cd; 2,4′-bpy=2,4′-bipyridine, 2-bpy=2,2′-bipyridine, phen=1,10-phenanthroline, L=HCOO−) were prepared in pure solid state. They were characterized by chemical, thermal and X-ray powder diffraction analysis, IR
spectroscopy, molar conductance in MeOH, DMF and DMSO. Examinations of OCO− absorption bands suggest versatile coordination behaviour of obtained complexes. The 2,4′-bpy acts as monodentate ligand; 2-bpy and phen as chelating ligands. Thermal studies were performed in static air atmosphere. When the temperature raised the dehydration
processes started. The final decomposition products, namely MO (Ni, Zn, Cd) and Mn3O4, were identified by X-ray diffraction.
Thorium(IV) complexes of the type Th(NO3)4·3L·2C2H5OH, Th(SCN)4·L·C2H5OH and Th(SO4)2·2L·2C2H5OH (L=1-butyl-1-methylpiperazinium iodide(I) have been synthesised. From thermogravimetric (TG) curves, the decomposition pattern
of the compounds has been analysed. The order, activation energy and apparent activation entropy of the thermal decomposition
reaction have been elucidated. The heat of reaction has been calculated from differential thermal analysis (DTA) studies.
Authors:Károly Bibok, Julia Coryell, and Saihua Xia
Book reviews of the following works: Istvan Kecskes: Situation-bound utterances in L1 and L2 (Studies on language acquisition, vol. 19). Mouton de Gruyter, Berlin & New York, 2003; Enikő Németh T. and Károly Bibok (eds): Pragmatics and the flexibility of word meaning} (Current research in the semantics\per pragmatics interface, vol. 8). Elsevier, Amsterdam, 2001.
Authors:H. Langfelderová, M. Hvasiijová, J. Kohout, P. Ambrovič, and K. Csomorová
The paper presents the results of a study of the course of thermal decomposition of complexes Cu(NCO)2L2 and Cu(LNCO)2, withL=pyrazole, 3,5-dimethylpyrazole, 3,4,5-trimethylpyrazole and indazole. The DTA curves of Cu(NCO)2L2 show exothermic excursions somewhat below the decomposition temperatures, corresponding to an inner complex nucleophilic addition of a carbon atom (from an NCO group) to the imine nitrogen atom of a pyrazole ligand. In this reaction the carbamoylpyrazolate anion is formed, coordinated to Cu(II). For these reactions the DSC method yielded the followingΔH values: −12.80 kJ mol−1 (L=pyrazole), −8.15 kJ mol−1 (L=3,5-dimethylpyrazole), −19.49 kJ mol−1 (L=3,4,5-trimethylpyrazole) and −11.59 kJ mol−1 (L=indazole). The course of thermal decomposition for Cu(NCO)2L2 after the nucleophilic addition is the same as for Cu(LNCO)2. The structure differences between the distortion isomers of Cu(NCO)2L2 and Cu(LNCO)2 were manifested in the decomposition temperatures and, in some cases, also in the stoichiometry of the decomposition reactions.
Authors:K. S. Bagga, L. W. Beineke, G. Chartrand, and O. R. Oellermann
For an (r − 2)-edge-connected graphG (r ≥ 3) for orderp containing at mostk edge cut sets of cardinalityr − 2 and for an integerl with 0 ≤l ≤ ⌊p/2⌋, it is shown that (1) ifp is even, 0 ≤k ≤ r(l + 1) − 1, and
Authors:V. Leovac, E. Ivegeš, K. Szécsényi, K. Tomor, G. Pokol, and S. Gal
Solvate complexes of UO22+ andN(1), N(4)-bis(salicylidene)-S-methylisothiosemicarbazone, (H2Me-L1), of general formula [UO2(Me-L1)S] (S= H2O, MeOH, EtOH, Py, DMF and DMSO) were synthesized. The methanolic UO22+” adducts of N(1)-benzoylisopropylidene-N(4)-salicylidene-S-alkylisothiosemicarbazone, (H2R-L2,R=Me, Prn) of general formula [UO2(R-L2)· MeOH], were also prepared. Thermal decomposition of the complexes was investigated in air and argon. The complexes decompose
to α-U3O8 in air, while in argon the decomposition is not completed up to 1000 K. The temperature and the mechanism of decomposition
of the complexes are a function of the solvent belonging to the inner coordination sphere.
The vacancy transfer probabilities of K to L1, L2 and L3 shell were measured with a new method. The L X-ray yields of targets excited by 59.5 keV incident photons, i.e., above the K edge of elements, were detected with a high-resolution Si(Li) detector. For comparison with the experimental results, theoretical calculations were made using data available on radiative and radiationless transitions. The radiative transition values of these elements were taken from the relativistic Hartree-Slater model, those of the radiationless transitions from the Dirac-Hartree-Slater model. The measured values were found to be in good agreement with theoretical ones. The hKLi (i = 1, 2, 3) values were calculated by measuring the L1x, L2x and L3x X-ray production cross-sections.
Authors:A. Mishra, S. Mishra, N. Manav, and N. Kaushik
Palladium(II) complexes of type [Pd(L)Cl2] [where L=2-aminopyridine-N-thiohydrazide (L1), (2-aminopyridine-N-thio)-1,3-propanediamine (L2), benzaldehyde 2-aminopyridine-N-thiohydrazone (L3) and salicylaldehyde-2-aminopyridine-N-thiohydrazone (L4)] have been synthesized. The thiohydrazide, thiodiamine and thiohydrazones can exist as thione-thiol tautomer and coordinate
as a bidentate N-S ligand. The ligands found to act in bidentate fashion.
The complexes have been characterized by elemental analysis, IR, mass, electronic, 1H NMR spectroscopic studies, and TG/DTA study. Antifungal studies of some complexes were also carried out. Various kinetic
and thermodynamic parameters like order of reaction (n), activation energy (Ea), apparent activation entropy (S#) and heat of reaction (ΔH) have also been carried out for one complex.
Thermal behaviour of a number of organomercury(II) complexes of the type, p-XC6H4HgCl(L1) (I), p-XC6H4HgCl3(L2) (II), p-XC6H4HgL3 (III) and p-XC6H4HgL4 (IV) [L1=isoniazid, L2=theobromine, L3=phenyldithiocarbamate, L4=p-nitrophenyldithiocarbamate; X=Me, MeO, NO2] has been investigated. From TG curves, the order and activation energy of the thermal decomposition reaction have been elucidated. The variation of the activation energy has been correlated with the nature of the substituent on the phenyl ring. The heat of reaction has been elucidated from DSC or DTA studies. The fragmentation pattern has been analysed on the basis of mass spectra.