Principal Volatile Products Research Articles

Characterization of Metal-Bound Benzimidazole Derivatives, Effects on Tumor Cells of Lung Cancer.

Four new ligands and four new copper (II) coordination compounds were prepared and characterized by chemical, elemental analysis, cytotoxicity, and FTIR spectroscopy (Fourier transform infrared spectroscopy). The nature of metal–ligand coordination was investigated. The thermal properties of complexes in the solid state were studied using TG-MS techniques (thermogravimetric analysis coupled with mass spectrometry) under dynamic flowing air atmosphere to analyze the principal volatile thermal decomposition and fragmentation products that evolved during thermolysis. The intermediate and final solid thermolysis products were also determined. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide) assay was used to evaluate active metabolic cells as an IC50 (half maximal inhibitory concentration). The relationship between antitumor activity and the position of nitrogen atoms in the organic ligand has been shown.

Analytical and thermal investigations of new solid Y(III) and La(III) complexes

New compounds with formulae Y(2,4′-bpy)1.5Cl3·8H2O (I), Y(2,4′-bpy)0.5Br3·8H2O (II), La(2,4′-bpy)Cl3·5H2O (III) and La(2,4′-bpy)1.5Br3·5H2O (IV) were prepared and characterized by chemical and elemental analysis, IR spectroscopy and powder X-ray diffraction. The thermal properties of compounds in the solid state were studied using TG-DTA techniques under dry air atmosphere. The thermal behavior of investigated compounds was studied in the temperature range 298–1273 K. They are stable up to 323 K. The complexes decompose in several stages, accompanied by endo- and exothermic effects. In all cases, the first step of pyrolysis is partial or total dehydration. When the temperature rises, deamination takes place. The solid final products of decomposition are Y2O3 and La2O3, respectively. Additionally, for all complexes mass spectrometry was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis under dry air atmosphere.

Synthesis, Spectroscopic, and Thermal Investigations of Metal Complexes with Mefenamic Acid

The novel metal complexes with empirical formulae M(mef)2·nH2O (where M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); mef is the mefenamic ligand) were synthesized and characterized by elemental analysis, molar conductance, FTIR-spectroscopy, and thermal decomposition techniques. All IR spectra revealed absorption bands related to the asymmetric (νas) and symmetric (νs) vibrations of carboxylate group. The Nakamoto criteria clearly indicate that this group is bonded in a bidentate chelate mode. The thermal behavior of complexes was studied by TGA methods under non-isothermal condition in air. Upon heating, all compounds decompose progressively to metal oxides, which are the final products of pyrolysis. Cu(II), Zn(II), and Cd(II) complexes were also characterized by the coupled TG-FTIR technique, which finally proved the path and gaseous products of thermal decomposition. Additionally, the coupled TG-MS system was used to determine the principal volatile products of thermolysis and fragmentation processes of Mn(mef)2·3H2O and Co(mef)2·2H2O.

Synthesis, thermal study and some properties of Zn(II), Cd(II) and Pb(II) compounds with mono-, di- and trichloroacetates

New complexes with formulae: Zn(CClH2COO)2·2H2O, Zn(CCl2HCOO)2·2H2O, Zn(CCl3COO)2·2H2O, Cd(CCl2HCOO)2·H2O, Cd(CCl3COO)2·2H2O and Pb(CCl3COO)2·2H2O, were prepared and characterized by chemical, elemental analysis and IR spectroscopy. The nature of metal–ligand coordination was studied. They are small crystalline. The thermal properties of compounds in the solid state were studied using TG–DTG techniques under dynamic flowing air atmosphere. Mass spectrometer was used to analyze principal volatile thermal decomposition and fragmentation products of Zn(CCl3COO)2·2H2O evolved during pyrolysis in dynamic flowing air and in argon atmosphere.

Synthesis, thermal study and some properties of Gd(III), Tb(III), Dy(III) and Er(III) complexes with 4,4′-bipyridine and dibromoacetates

New complexes with formulae: Ln(4-bpy)(CBr2HCOO)3·3H2O (where Ln(III) = Gd, Tb, Dy) and Er(4-bpy)1.5(CBr2HCOO)3·3H2O, were prepared and characterized by chemical, elemental analysis and IR spectroscopy. The nature of metal–ligand coordination was studied. All of them are crystalline. Gd(III), Tb(III) and Dy(III) complexes are isostructural in one group. Conductivity studies (in methanol, dimethyloformamide and dimethylsulfoxide) were also discussed. The thermal properties of complexes in the solid state were studied using TG–DTG techniques under dynamic flowing air atmosphere. TG–MS system was used for Tb(III) (as an example of isostructural compound) and Er(III) complexes to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis in dynamic flowing air atmosphere.

Mass loss by SU-8 polymer under X-ray irradiation

The principal volatile products forming in air degradation of SU-8 polymer under influence of synchrotron radiation in the wavelength range of 2.5–0.25 A have been studied. The material degradation products such as hydrogen, acrolein, acetone, allyl alcohol, benzene, and methyl formate have been identified, as well as atmospheric products. However, the most often products of outgassing are water and carbon oxide molecules, which contribute to the mass loss of the polymer irradiated.

Synthesis and some properties of light lanthanide complexes with 4,4′-bipyridine and dibromoacetates

In this study, new complexes with formulae: Ce(4-bpy)(CHBr2COO)3·H2O, Ln(4-bpy)0.5(CHBr2COO)3·2H2O (where Ln(III) = Pr, Nd, Sm; 4-bpy = 4,4′-bipyridine) and Eu(4-bpy)(CHBr2COO)3·2H2O were prepared, and characterized by chemical and elemental analyses, and IR spectroscopy. The way of metal–ligand coordination was discussed. They are small crystalline. The complexes of Pr(III), Nd(III), and Sm(III) are isostructural in group. Conductivity studies (in methanol, dimethylformamide, and dimethylsulfoxide) were also performed and described. The thermal properties of complexes in the solid state were studied using TG–DTG techniques under dynamic flow of air atmosphere. TG–MS system was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolyses of Ce(III) and Sm(III) complexes in dynamic flow of air atmosphere.

Synthesis, thermal behavior, and other properties of Y(III) and La(III) complexes with 4,4′-bipyridine and trichloro- or dibromoacetates

New Y(III) and La(III) complexes with 4-bpy (4,4′-bipyridine) and trichloro- or dibromoacetates with the formulae: Y(4-bpy)2(CCl3COO)3·H2O I, La(4-bpy)1.5(CCl3COO)3·2H2O II, Y(4-bpy)1.5(CHBr2COO)3·3H2O III, and La(4-bpy)(CHBr2COO)3·H2O IV were prepared and characterized by chemical, elemental analysis, and IR spectroscopy. Conductivity studies (in methanol, dimethyloformamide, and dimethylsulfoxide) were also described. They are small, crystalline substances. The way of metal–ligand coordination was discussed. The thermal properties of complexes in the solid state were studied by TG-DTG techniques under dynamic flowing air atmosphere. TG-FTIR system was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis in dynamic flowing argon atmosphere for La(III) compounds.

Study on pentaerythritol–zinc as a novel thermal stabilizer for rigid poly(vinyl chloride)

AbstractPentaerythritol–zinc (penzinc) was prepared by a solid‐phase reaction technique. The principal volatile products of the reaction between pentaerythritol and ZnO were analyzed with a coupled thermogravimetry—mass spectrometery system. The results indicated that a large amount of water was formed at the reaction temperature. Scanning electron microscopy (SEM) results showed the appearance of penzinc as flaky particles. Accordingly, the penzinc obtained through the dehydration between pentaerythritol and ZnO is likely to be a monopentaerythritol complex, such as zinc monoglycerolate. The thermal stability of poly(vinyl chloride) (PVC) with penzinc as a thermal stabilizer was investigated by a Congo Red test, Oven aging test and thermal gravimetric analysis (TGA). The Congo Red test showed the thermal stability time of PVC with penzinc was 38 min, longer than those with commercial thermal stabilizers. TGA indicated that the penzinc had little impact on the thermal degradation of PVC, but could increase the mass of residues. Oven aging test showed that the penzinc could significantly retard the discoloration during the long‐term decomposition of PVC. Meanwhile, no “zinc burning” was observed in the PVC with penzinc. These results indicate that the penzinc is an excellent thermal stabilizer for rigid PVC. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Pyrolysis study of hydrophobic tholins By TG-MS, TG, DTA and DSC methods

This study presents the thermogravimetry (TG) of hydrophobic tholins, obtained from different simulation experiments of prebiotic synthesis carried out in a CH4/N2/H2 atmosphere with spark discharge activation of aqueous aerosols and liquid water. Differential thermal analysis and differential scanning calorimetry were also used to evaluate the thermal behaviour of these complex organic compounds that could play an important role in prebiotic chemistry. A coupled thermogravimetry-mass spectrometry system allowed us to analyse the principal volatile thermal decomposition and fragmentation products of the hydrophobic tholins under dynamic conditions and an inert atmosphere. During their thermal degradation, which occurs in two stages, a wide variety of hydrocarbon products including methane, vinyl monomers (such as ethylene and propylene), acetylene, oligomers, and some other unknown compounds are found. Besides, a thermally stable structure is present (graphitic structure) in these particular organic substances. Finally, data collected from TG experiments in an oxidative atmosphere showed significant differences at temperatures above 240 °C. According to these results, the different techniques of thermal analysis here applied have proved to be an adequate methodology for the study and characterization of these complex systems, structures of which remain controversial even in these days.

Thermal behavior and other properties of Pr(III), Sm(III), Eu(III), Gd(III), Tb(III) complexes with 4,4′-bipyridine and trichloroacetates

A novel mixed-ligand complexes with empirical formulae: Ln(4-bpy)1.5(CCl3COO)3·nH2O (where Ln(III) = Pr, Sm, Eu, Gd, Tb; n = 1 for Pr, Sm, Eu and n = 3 for Gd, Tb; 4-bpy = 4,4′-bipyridine) were prepared and characterized by chemical, elemental analysis and IR spectroscopy. Conductivity studies (in methanol, dimethylformamide and dimethylsulfoxide) were also described. All complexes are crystalline. The way of metal–ligand coordination was discussed. The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During heating the complexes decompose via intermediate products to the oxides: Pr6O11, Ln2O3 (for Sm, Eu, Gd) and Tb4O7. TG-MS system was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis of Pr(III) and Sm(III) compounds in air.

Thermal characterization of HCN polymers by TG–MS, TG, DTA and DSC methods

This paper presents a thermogravimetry (TG) study of hydrogen cyanide polymers, synthesized from the reaction of equimolar aqueous solutions of sodium cyanide and ammonium chloride. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were also used to evaluate the thermal behaviour of these black polymers, which play an important role in prebiotic chemistry. A coupled TG–mass spectrometer (MS) system allowed us to analyze the principal volatile thermal decomposition and fragmentation products of the isolated HCN polymers under dynamic conditions and an inert atmosphere. After dehydration, a multi-step decomposition occurred in this particular polymeric system, due to the release of ammonia, hydrogen cyanide (depolymerization reaction), isocyanic acid (or cyanic acid) and formamide; these two latter species allow us identify bond connectivities. Finally, data collected from TG experiments in an oxidative atmosphere showed significant differences at higher temperatures, above 400 °C. According to these results, the different techniques of thermal analysis here applied have demonstrated to be an adequate methodology for the study and characterization of this complex macromolecular system, whose structure remains controversial even today.

Zinc(II) and cadmium(II) complexes with o-hydroxybenzoic acid or o-aminobenzoic acid and 2-methylimidazole

Mixed complexes of the type: Zn(Hsal)2(2-MeHim)2, Zn(Han)2(2-MeHim)2, Cd(Hsal)2(2-MeHim)2, Cd(Han)2(2-MeHim)2, where Hsal=OHC6H4COO−, Han=NH2C6H4COO−, 2-MeHim=2-methylimidazol) have been synthesized and characterized by IR spectroscopic and X-ray diffraction studies. Single-crystal X-ray structure of Cd(Hsal)2(2-MeHim)2 has been obtained. Thermal behaviour of the compounds was investigated by thermal analysis (TG, DTG, DTA). A coupled TG-MS system was used to analyse the principal volatile products of complexes. Thermal decomposition pathways have been postulated.

Novel Co(II) and Cd(II) complexes with non-steroidal anti-inflammatory drugs

Abstract New metal(II) complexes with empirical formulae Co(ibup)2·4H2O, Cd(ibup)2·3H2O, Co(nap)2·H2O, Cd(nap)2·3H2O (where ibup=(CH3)2CHCH2C6H4CH(CH3COO−) and nap=CH3O(C10H6)CH(CH3COO−)) were isolated and investigated. The complexes were characterized by elemental analysis, molar conductance, IR spectroscopy and thermal decomposition. The thermal behavior was studied by TG, DTG, DTA methods under non-isothermal conditions in air atmosphere. The hydrated complexes lose water molecules in first step. All complexes decompose via intermediate products to corresponding metal oxides CoO and CdO. A coupled TG-MS system was used to detect the principal volatile products of thermolysis and fragmentation processes of Co(nap)2·H2O. The IR spectra of studied complexes revealed also absorption of the carboxylate group. Principal concern with the position of asymmetric, symmetric frequencies. The value of their separation allow to deduce about type of coordination these groups.

Thermal characterization of new complexes of Zn(II) and Cd(II) with some bipyridine isomers and propionates

Abstract New mixed ligand complexes of the following stoichiometric formulae: M(2-bpy)2(RCOO)2·nH2O, M(4-bpy)(RCOO)2·H2O and M(2,4’-bpy)2(RCOO)2·H2O (where M(II)=Zn, Cd; 2-bpy=2,2’-bipyridine, 4-bpy=4,4′-bipyridine, 2,4′-bpy=2,4′-bipyridine; R=C2H5; n=2 or 4) were prepared in pure solid-state. These complexes were characterized by chemical and elemental analysis, IR and conductivity studies. Thermal behaviour of compounds was studied by means of DTA, DTG, TG techniques under static conditions in air. The final products of pyrolysis of Cd(II) and Zn(II) compounds were metal oxides MO. A coupled TG/MS system was used to analyse of principal volatile products of thermal decomposition or fragmentation of Zn(4-bpy)(RCOO)2·H2O under dynamic air and argon atmosphere. The principal species correspond to: C+, CH+, CH3 +, C2H2 +, HCN+, C2H5 + or CHO+, CH2O+ or NO+, CO2 +, 13C16O2 + and 12C16O18O+ and others; additionally CO+ in argon atmosphere.

Channel-containing structure built of 3D sodium nitrate coordination polymer

The three-dimensional channel structure of catena-((μ 3-hexamethylenetetraamine)-tris-(μ 3-nitrato)-tri-sodium), [(NaNO3)3 · (CH2)6N4] n , is presented. The sodium is seven coordinate with a distorted capped trigonal prism geometry. During heating the hexamethylenetetraamine can be removed from the compound. The principal volatile thermal decomposition and fragmentation products correspond to: C+, , NO+, N2O+.

IR spectra, X-ray diffraction studies and thermal analysis of cadmium(II) complexes with o-aminobenzoic acid and imidazoles

Mixed complexes of the type: Cd(Han) 2(Him) 4, Cd(Han) 2(Him) 5, Cd(Han) 2(4-MeHim) 4, Cd(Han) 2(1,2-diMeim) 2 (where Han = NH 2C 6H 4COO −, Him = imidazole, 4-MeHim = 4-methylimidazole, 1,2-diMeim = 1,2-dimethylimidazole) have been synthesized and characterized by IR spectroscopic and X-ray powder diffraction studies. Thermal behaviour of compounds was investigated by thermal analysis (TG, DTG, DTA). A coupled TG-MS system was used to analyse of the principal volatile products of the complexes. Thermal decomposition pathways have been postulated for synthesized complexes.

TG-MS, TG, DTG and DTA methods in study of thermal decomposition of some d-metal complexes with 4,4'-bpy and propionates

The new mixed ligand complexes with formulae M(4-bpy)(C2H5COO)2·2H2O (where M(II)=Mn, Co, Ni; 4,4'-bpy or 4-bpy=4,4'-bipyridine) and Cu(4-bpy)0.5(C2H5COO)2·H2O were prepared and characterized by VIS (for solid compounds of Co(II), Ni(II), Cu(II) in Nujol), IR spectroscopy, X-ray powder diffraction and molar conductance in MeOH, DMF or DMSO. Thermal behaviour of complexes was studied under static conditions in air atmosphere. Corresponding metal oxides were identified as final products of pyrolysis. A coupled TG-MS system was used to analysis of principal volatile thermal decomposition and fragmentation products of isolated complexes under dynamic air and argon atmosphere. The principal species correspond to: C+, OH+, H2O+, NO+, CO2+ and other; additionally CO+ in argon atmosphere.

Characterization and TG-MS studies of lactato and bipyridine-lactato complexes of Co(II) and Ni(II)

Two lactates and four new mixed ligand complexes with formulae Co(lact)2·2H2O, Ni(lact)2·3H2O, Co(4-bpy)(lact)2, Co(2,4'-bpy)2(lact)2, Ni(4-bpy)(lact)2·2H2O and Ni(2,4'-bpy)2(lact)2 (where 4-bpy=4,4'-bipyridine, 2,4'-bpy=2,4'-bipyridine, lact=CH3CH(OH)COO-) were isolated and investigated. The thermal behaviour of compounds was studied by thermal analysis (TG, DTG, DTA). In the case of hydrated complexes thermal decomposition starts with the release of water molecules. The compounds decompose at high temperature to metal(II) oxides in air. A coupled TG-MS system was used to analyse the principal volatile products of thermolysis and fragmentation processes of obtained complexes.

Synthesis, thermal and other studies of 2,4'-bipyridine-dichloroacetato complexes of Mn(II), Co(II), Ni(II) and Cu(II)

Four new mixed ligand complexes were prepared by the reaction of title metal dichloroacetates and 2,4'-bipyridine. The general formulae of synthesized compounds are M(2,4'-bpy)2(CCl2HCOO)2·nH2O (where M(II)=Mn, Co, Ni, Cu; 2,4'-bpy=2,4'-bipyridine, n=2 or 4). The complexes have been isolated from aqueous media and characterized by chemical analysis, molar conductance (in MeOH, DMSO and DMF), magnetic, IR and VIS spectral studies. The nature of metal(II)-ligand coordination is discussed. The thermal behaviour of obtained complexes was studied by thermal analysis and TG-MS techniques in air. IR, X-ray powder diffraction and thermoanalytical data were used for the determination of solid intermediate products of the thermal decomposition. The principal volatile products of thermal decomposition of complexes were proved by mass spectroscopy: H2O+, CO+2, HCl+2, Cl+2, NO+ and other.