Authors:Mihaela Badea, Rodica Olar, Dana Marinescu, Veronica Lazar, Carmen Chifiriuc, and Gina Vasile
This paper reports the investigation on the thermal stability of new complexes with mixed ligands of the type [Cd(NN)(C3H3O2)2(H2O)m]·nH2O [(1) NN: 1,10-phenantroline, m = 1, n = 0; (2) NN: 2,2′-bipyridine, m = 0, n = 1.5 and (C3H3O2): acrylate anion]. The IR data indicate a bidentate coordination mode for both heterocyclic amine and acrylate. The in vitro
qualitative and quantitative antimicrobial activity assays showed that the complexes exhibited variable antimicrobial activity
against planktonic as well as biofilm embedded Gram-negative (Escherichiacoli, Klebsiella sp., Proteus sp., Salmonella sp., Shigella sp., Acinetobacterboumani, Pseudomonasaeruginosa), Gram-positive (Bacillussubtilis, Staphylococcusaureus) and fungal (Candida albicans) strains, reference and isolated ones from the hospital environment. The thermal behaviour steps were investigated
in synthetic air flow. The thermal transformations are complex processes according to TG and DTA curves including dehydration,
amine as well as acrylate thermolysis. The final products of decomposition are the most stable metal oxides.
, complexes of 2,2′-bipyridine and 2,2′ bipyridine N , N ′-dioxide with ions of transition metals are reported in the literature [ 2 – 4 ]. The coordination takes place through the two nitrogen atoms or the two oxygen atoms, respectively, leading to the
Authors:Andrea Melchior, Marilena Tolazzi, and Silvia Del Piero
, Toftlund H , Hazell A , Bourassa J , Ford PC . Crystal structure, luminescence and other properties of some lanthanide complexes of the polypyridine ligand 6,6′-bis[bis(2-pyridylmethyl) aminomethyl]-2,2′-bipyridine . J Chem Soc
The [InCl3(L)n] (where L is 2,2′-bipyridine (bipy), 2,2′-bipyridine N,N′-dioxide (bipyNO), N,N-dimethylacetamide (dma), urea (u), thiourea (tu) or 1,1,3,3-tetramethylthiourea (tmtu); n = 1.5, 3 or 4) were synthesized and characterized by melting points, elemental analysis, thermal analysis and IR spectroscopy.
The enthalpies of dissolution of the adducts, Indium(III) chloride and ligands in 1.2 M aqueous HCl were measured and by using
thermochemical cycles, the following thermochemical parameters for the adducts have been determined: the standard enthalpies
for the Lewis acid/base reactions (ΔrHθ), the standard enthalpies of formation (ΔfHθ), the lattice standard enthalpies (ΔMHθ), and the standard enthalpies of decomposition (ΔDHθ).
Authors:H. Ye, N. Ren, H. Li, J. Zhang, S. Sun, and L. Tian
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.
Authors:D. Czakis-Sulikowska, J. Kałużna, and J. Radwańska-Doczekalska
The complexes of the general formula MLSCN (M=Cu(I), Ag(I), L=2,2′-bipyridine=2-bipy, 4,4′-bipyridine=4-bipy or 2,4′-bipyridine=2,4′bipy)
have been prepared and their IR spectra examined. The nature of metal-ligand coordination is discussed. Thermal decomposition
in air of these complexes occurred in several successive endothermic and exothermic processes and the residue was Cu2O and Ag, respectively.
Authors:J.-J. Zhang, R.-F. Wang, J.-B. Li, H.-M. Liu, and H.-F. Yang
The thermal decomposition of Eu2(BA)6(bipy)2 (BA=C2H5N–2, benzoate; bipy=C10H8N2, 2,2'-bipyridine)and its kinetics were studied under the non-isothermal condition by TG-DTG, IR and SEM methods. The kinetic
parameters were obtained from analysis of the TG-DTG curves by the Achar method, the Madhusudanan-Krishnan-Ninan (MKN) method,
the Ozawa method and the Kissinger method. The most probable mechanism function was suggested by comparing the kinetic parameters.
The kinetic equation for the first stage can be expressed as: dα/dt=Aexp(–E/RT)3(1–α)2/3.
Authors:Crislene Morais, C. Gameiro, P. Santa-Cruz, S. Alves Jr, L. Soledade, and A. Souza
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 5C min–1.
A novel metal-organic frameworks [Cu2(OH)(2,2′-bpy)2(BTC) · 2H2O]n (CuMOF, BTC = benzene-1,3,5-tricarboxylic acid, 2,2′-bpy = 2,2′-bipyridine) has been synthesized hydrothermally and characterized
by single crystal XRD, FT-IR spectra. The low-temperature molar heat capacities were measured by temperature modulated differential
scanning calorimetry (TMDSC) for the first time. The thermodynamic parameters such as entropy and enthalpy relative to reference
temperature 298.15 K were derived based on the above molar heat capacity data. Moreover, the thermal stability and the decomposition
mechanism of CuMOF were investigated by TG-MS (thermogravimetry-mass spectrometer). A four-stage mass loss was observed in
the TG curve. MS curve indicated that the gas products for oxidative degradation of CuMOF were H2O, CO2, NO and NO2.
Authors:Silvia Piero, Andrea Melchior, Davide Menotti, Marilena Tolazzi, and Anders Døssing
An investigation on the thermodynamics of complex formation between Ag(I) ion and two tripodal ligands tris[(2-pyridyl)methyl]amine
(TPA) and 6,6′-bis-[bis-(2-pyridylmethyl)aminomethyl]-2,2′-bipyridine (BTPA) has been carried out in the aprotic solvents
dimethylsulfoxide (DMSO) and dimethylformamide (DMF) by means of potentiometry and titration calorimetry. The results for
TPA are compared with those already obtained for other aliphatic tripodal polyamines. In general, the TPA ligand forms complexes
less stable than 2,2′,2″-triaminotriethylamine (TREN) and tris(2-(methylamino)ethyl)amine (Me3TREN) as a result of the combination of higher structural rigidity of TPA and lower σ-donor ability of pyridinic moieties
with respect to primary and secondary amines. The same trend is found if the stability of Ag(I) complex with TPA is compared
with that of tris(2-(dimethylamino)ethyl)amine (ME6TREN), despite the pyridinic nitrogen is formally a tertiary one. Theoretical calculations run to explain the reasons of this
weaker interaction indicate that this difference is due to solvation, rather than to steric or σ-donor effects. The ligand
BTPA is able to form bimetallic species whose relative stability is largely influenced by the different solvation of Ag(I)
ion in DMSO and DMF rather than by the difference in the dielectric constants of these two media.