The intermediates formed from Mo(NO)2Cl2L2 and Mo(NO)Cl3L2 by splitting-off of weakly-coordinated ligandsL (alcohols, glycols, nitriles) decompose in exothermic reactions: the decomposition products are N2, MoOCl4 and MoO3. If the ligandL is strongly coordinated and is reducing (DMFA, DMSO, Pph3, Asph3), the NO groups oxidize the ligandL by formation of N2 in an exothermic intramolecular redox process under 300‡. The central atom is oxidized by NO, and N2O is formed above 300‡ in the case of non-reducing ligandsL (OPph3, OAsph3). An endothermic redox reaction with chlorine formation is observed during decomposition of the trichloro complex. The solid residue is metallic molybdenum.
The complex formation of curium(III) with L2-aminobutyric acid was characterized by time-resolved laser-induced fluorescence
spectroscopy (TRLFS) at trace Cm(III) concentrations (3·10−7 M). The various curium(III) species, MpHqLr, identified are characterized by their individual luminescence spectra and luminescence lifetimes. The following formation
constants were determined log β101 = 5.17±0.07, log β102 = 9.00±0.07, and log β103 = 11.30±0.09 at ionic strength I = 0.5M. Possible structures of the curium aminobutyrate species will be discussed on the basis of the luminescence lifetime
measurements and the magnitude of the formation constants.
Authors:M. Kabešová, I. Vargová, T. Šramko, and J. Gažo
The influence of the position of the CH3 group in picoline and lutidine ligands on the degree of chemical change of the NCS groups in coordination compounds of the type Cu(NCS)2L2 (whereL=2-, 3- and 4-picoline, and 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-lutidine) is dealt with. The most marked effect of the CH3 group is found to be exerted in position 4. This effect of the methyl group on the degree of chemical change points to the mutual influence of the ligands in coordination compounds of Cu(II).
Authors:L. Nagy, J. Zsakó, Cs. Novák, Cs. Várhelyi, Gy. Vankó, and G. Liptay
A number of 15 [Fe(Diox#x00B7;H)2L2] type chelates and [Fe(Diox)3(BOR)2] clathrochelates (Diox#x00B7;H2 — dimethylglyoxime, glyoxime, propoxime, nyoxime, furyl-dioxime; L-pyridine, alkyl-pyridine derivatives, diethyl-phenyl-phosphine, diethyl-p-tolyl-phosphine) were obtained and characterized by means of far and middle FTIR and Mössbauer spectroscopic methods. Some structural problems were discussed on the basis of the optical data.The DSC measurements show the higher thermal stability of the clathrochelates without O—HO intramolecular hydrogen bonds (with asymmetric octahedral structure), as compared to the [Fe(Diox#x00B7;H)2L2] trans, symmetric chelates containing O—HO bonds. The kinetic parameters of the thermal decomposition of the complexes have been derived using the nomogram method.
We report the temperature dependence of Mössbauer spectra of a mixed-valence dinuclear Fe(II) Fe(III) complex, [Fe2(bpmp)(Ph(CH2)2COO−)2](BF4)2 1, where Hbpmp represents 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol. Two quadrupole doublets observed at 78
K approach each other as the temperature is increased. The two high-energy components of a doublet due to Fe(II) and of that
due to Fe(III) become broad in the temperature range from 78 to 230 K and then become narrow above 260 K. The temperature
dependence of the spectra was interpreted by assuming of intramolecular electron exchanges between two energetically inequivalent
vibronic states FeA(II)FeB(III) and FeA(III)FeB(II) where one of them is slightly more stable than the other.
Authors:P. Aslanidis, K. Chrissafis, and M. Lalia-Kantouri
photoluminescence properties of four cationic dimeric copper (I) halide complexes, formulated as [(L) 2 Cu(μ 2 -L) 2 Cu(L) 2 ] 2+ 2χ − , where X = Cl, Br and L = pyridine-2-thione (py2SH), or 4,6-dimethylpyrimidine-2-thione (dmpymtH) were studied. A further
,10-phenanthroline-5,6-dione)(4,4′-dicarboxy-2,2′-bipyridyl)ruthenium(II)], cis -[Ru(L1)(L2)(NCS) 2 ] (where the ligands were L1 = 1,10-Phenanthroline-5,6-dione and L2 = 4,4′-dicarboxy-2,2′-bipyridyl). The decomposition mechanism was also suggested for ruthenium
Authors:K. Chrissafis, M. Lalia-Kantouri, and P. Aslanidis
decomposition kinetics of such complexes, two series of copper (I) halide complexes formulated as [(L)CuX(μ 2 -L) 2 CuX(L)] and [(L) 2 Cu(μ 2 -L) 2 Cu(L) 2 ] 2+ 2χ − , respectively (X = Cl, Br and L = 4,6-dimethylpyrimidine-2-thione (dmpymtH)) were studied and