Authors:R. Verma, L. Verma, M. Ranjan, B. Verma, and S. Mojumdar
A series of ternary complexes of the types M2L′2L″2;ML′2L″2 (M=Fe, Cu, Zn; L′=2-oxocyclopentane dithiocarboxylate; L″=pyridine, morpholine) and CuL′2H2O was prepared afresh. Except the iron complex, all are dimer and complexation is through the dithio moiety of the ligand
L′. Their thermal decomposition was carried out in air at heating rate 10°C min−1 and it revealed that the dehydration of the aqua complex follows the same path as the carboxylates and the pyridine complexes
have the tendency to follow one-step decomposition. The copper complexes are less thermally stable. The overall thermal stability
of the 2-oxocyclopentanedithiocarboxylato complexes of the three metals with the volatile ligands was found to be in the order:
(CuLmorph)2< CuL2H2O<(CuLpy)2<(ZnLmorph)2<(ZnLpy)2<FeL2py2. The thermogravimetric properties of the complexes have been studied and the data were subjected to kinetic analysis. The
values of n, E, A and ΔS# have been approximated and compared. Any formation of bridged structure is not indicated in the first step case.
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.
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: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.
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: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 compounds [PdCl2L2] and [PdL4] (L=PPh3, AsPh3, SbP3) were studied by thermogra-vimetric and differential thermal analyses in air. The residues of thermal decomposition consist
of metallic palladium, except in the case of the complexes containing SbPh3, when the residues are palladium and antimony mixtures in appropriate proportions with respect to the stoichiometry of the
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