D. Todorovsky - Academia.edu (original) (raw)
Papers by D. Todorovsky
Canadian Journal of Chemistry, 2007
The composition, some spectral characteristics, and thermal decomposition of solid lanthanide–tit... more The composition, some spectral characteristics, and thermal decomposition of solid lanthanide–titanium (lanthanide (Ln) = Y, La, Ce) and lanthanide–titanium citrates (CA) and tartrates (TA) have been studied. The complexes have been prepared in ethylene glycol medium at conditions modeling those of the polymerized-complex method applied for Ln2Ti2O7 preparation. Special attention has been paid to the chemical nature of the bimetallic products as well as to the factors influencing the deprotonation of the alcoholic OH groups of the acidic ligands. The results contribute to further elucidation of the complexation and thermal decomposition processes involved in the polymerized-complex method.Key words: inorganic compounds, sol–gel chemistry, infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA).
Key Engineering Materials, 2004
... [10] D. Todorovsky, M. Getsova and M. Milanova: Synth. Reactivity in Inorg. Metal-Org. Chem. ... more ... [10] D. Todorovsky, M. Getsova and M. Milanova: Synth. Reactivity in Inorg. Metal-Org. Chem. Vol. 33 (2003), p. 223. [11] D. Todorovsky, N. Petrova: Ann. Univ. Sofia Fac. Chim. Vol. 96 (2003) (in press). [12] M. Getsova, D. Todorovsky, I. Wawer and V. Enchev (to be publiched). ...
Materials Letters, 2004
La-, Ti-and La-Ti-citrates, prepared in ethylene glycol medium (at conditions similar to those us... more La-, Ti-and La-Ti-citrates, prepared in ethylene glycol medium (at conditions similar to those used in the polymerized complex method) and isolated as solid substances, have been studied by 13 C-solid state NMR analysis, XPS, SEM and EDAX. The obtained results, together with data from elemental, thermogravimetric, IR, 13 C-and 1 H-NMR (in solution) analysis, give evidence for the mixed-metal nature of the bimetallic citric complex and permit a hypothetical structure to be proposed.
Synthesis and Reactivity in Inorganic and Metal-organic Chemistry, 2003
The composition, IR, C and H NMR spectral characteristics and thermochemical behavior of La‐, Ti‐... more The composition, IR, C and H NMR spectral characteristics and thermochemical behavior of La‐, Ti‐ and bimetallic La‐Ti‐tartrates (potential precursors of La2Ti2O7), obtained in ethylene glycol, were studied. The comparison of their main characteristics with those of the analogous citric complexes contributes to the elucidation of the processes involved in the complexation and thermal decomposition of such complexes. The bimetallic
Monatshefte für Chemie - Chemical Monthly, 2007
Cerium(III=IV) and Ce(IV)-Ti(IV) citric complexes were synthesized in ethylene glycol medium unde... more Cerium(III=IV) and Ce(IV)-Ti(IV) citric complexes were synthesized in ethylene glycol medium under conditions similar to those of the polymerized complex method (PCM). Solution phase 1 H, 13 C NMR, solid state 13 C CP MAS NMR and IR spectroscopy, and X-ray powder diffractometry were used to characterize the composition and structure of the synthesized products. Thermal decomposition of the isolated complexes was studied and a scheme of the processes taking place is proposed. Complexes of Ce(III) can be prepared at low temperature (40 C), only. In the presence of Ti(IV) ions, the oxidation takes place even at this temperature. A mixed-metal nature of the Ce(IV)-Ti(IV) complexes is established. The comparison between their composition and the one of analogous lanthanide(III)-Ti(IV) citrates contributes to the elucidation of the complexation process mechanism in the case of the PCM application. The increased charge of the complexation agent in the Ce 4þ-Ti 4þ complex (in comparison with Ln 3þ-Ti 4þ citrates) is ''compensated'' by the increase of the relative number of the ligands with deprotonated OH group.
Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors... more Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors for YFeO 3 and Y 3 Fe 5 O 12 thin films preparation, have been synthesized in ethylene glycol medium. The compositions, IR, 1 H and 13 C NMR spectral characteristics of the isolated solid complexes have been studied. Their chemical nature and the peculiarities of the complexation process in the system Y III-Fe IIIcitric acid-ethylene glycol = 1 : 1 : 8.5 : 35 have been studied and compared with those of the earlier studied lanthanide(III or IV)-titanium(IV) citric acid complexes, prepared under the same conditions. The mixed-metal nature of the obtained complexes has been shown. In contrast to the analogous lanthanide-titanium system, no deprotonation of the alcoholic OH groups of citric ligands takes place in the course of the formation of Y-Fe complexes.
The paper addresses the thermal decomposition of La-, Ti- and bimetallic La-Ti-non-crystalline ci... more The paper addresses the thermal decomposition of La-, Ti- and bimetallic La-Ti-non-crystalline citric complexes, prepared in ethylene glycol medium. The latter complex is the starting material for the effective ferroelectric La2Ti2O7 preparation by the polymerized complex method. Based on thermogravimetric analysis (DTG, DTA and TG) and identification of some of the intermediates (by elemental analysis, NMR and IR spectroscopy and
ChemInform, 2005
For Abstract see ChemInform Abstract in Full Text.
Zeitschrift für anorganische und allgemeine Chemie, 2000
Yttrium, titanium, and yttrium-titanium citrate complexes are synthesized in ethylene glycol medi... more Yttrium, titanium, and yttrium-titanium citrate complexes are synthesized in ethylene glycol medium at conditions similar to those used when the polymerized complex method (a version of the sol-gel technology) is applied. The composition and IR, 1H and 13C NMR spectral characteristics of the isolated solid state complexes are studied. Proofs of the mixed metal nature of the bimetallic complexes are reported. The conditions of deprotonation of the alcoholic OH group of the citrate ligands are considered. Darstellung und Charakterisierung von Yttrium–Titan-Citratkomplexen Yttrium-, Titan- und Yttrium–Titan-Citratkomplexe wurden in Ethylenglykol unter ahnlichen Bedingungen wie bei der Komplexpolymerisation (Sol-Gel-Technik) synthetisiert. Die Zusammensetzung sowie IR-, 1H- und 13C-NMR spektroskopischen Charakteristika der isolierten festen Komplexe wurden bestimmt bzw. untersucht. Hinweise auf die gemischtmetallische Natur der Bimetallkomplexe werden angegeben. Die Bedingungen der Deprotonierung der alkoholischen OH-Gruppe der Citratliganden werden diskutiert.
Depleted U 3 O 8 was mechanically activated in suspension with tributyl phosphate (TBP), trioctyl... more Depleted U 3 O 8 was mechanically activated in suspension with tributyl phosphate (TBP), trioctylamine (TOA) and ethylenglycolmonomethylether (EGME) in planetary ball mill with stainless steel vessels and balls. X-ray diffractograms and IR spectra of the activated solid samples were taken. The radioactivities of 238 U and 234 Th in the leaching solutions were determined by α/β liquid scintillation spectrometry. The reduction degree of the oxide, the mean crystallite size of U 3 O 8 and U 3 O 7 and the leaching of 238 U and 234 Th as a result of the mechanoactivation were determined. Higher degree of 238 U and 234 Th leaching was achieved when mechanoactivation with TBP was performed. No leaching of 238 U daughter product ( 234 Th) proceeded at mechanoactivation with TOA and EGME. The role of the solvents complexation ability, milling induced increase of crystal defect concentration and UO 2 – ThO 2 solid solution formation is discussed. Further studies have to be made to elucidate t...
Ru(II)-tris (4,7-diphenyl-1,10-phenanthroline) dichloride immobilized in matrices from sol-gel pr... more Ru(II)-tris (4,7-diphenyl-1,10-phenanthroline) dichloride immobilized in matrices from sol-gel produced SiO2, SiO2-citric acid/ethylene glycol polyester hybrid or poly (methylmetacrylate) is explored as a sensor for determination of dissolved oxygen in white and red wines. The significant overlapping of the 612 nm spectral bands of the oxygensensitive chromophore with the analyzed products band imposes the necessity of accounting for the impact of the latter in the analysis. The SiO2-based composite is rather sensitive to the prolonged action of wine causing a disturbance of the linearity of the Stren-Volmer dependence and significant decrease of the respective constant.
Bulgarian Chemical Communications, 1996
Etude du comportement au recuit de 35 S produit dans des cristaux mixtes AlCl 3 −FeCl 3 irradies ... more Etude du comportement au recuit de 35 S produit dans des cristaux mixtes AlCl 3 −FeCl 3 irradies dans une pile: l'etat chimique de 35 S est defini par la prehistoire de la cible et la concentration en Fe
Bulgarian Chemical Communications, 1996
Etude des retentions des orthophosphates et des phosphates totaux dans les orthophosphates alcali... more Etude des retentions des orthophosphates et des phosphates totaux dans les orthophosphates alcalins irradies par les neutrons et contenant differentes quantites d'eau de cristallisation
Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors... more Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors for YFeO 3 and Y 3 Fe 5 O 1 2 thin films preparation, have been synthesized in ethylene glycol medium. The compositions, IR, 1 H and 1 3 C NMR spectral characteristics of the isolated solid complexes have been studied. Their chemical nature and the peculiarities of the complexation process in the system Y I I I -Fe I I I -citric acid-ethylene glycol 1 : 1 : 8.5 : 35 have been studied and compared with those of the earlier studied lanthanide(III or IV)-titanium(IV) citric acid complexes, prepared under the same conditions. The mixed-metal nature of the obtained complexes has been shown. In contrast to the analogous lanthanide-titanium system, no deprotonation of the alcoholic OH groups of citric ligands takes place in the course of the formation of Y-Fe complexes.
ChemInform, 2001
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Canadian Journal of Chemistry, 2007
The composition, some spectral characteristics, and thermal decomposition of solid lanthanide–tit... more The composition, some spectral characteristics, and thermal decomposition of solid lanthanide–titanium (lanthanide (Ln) = Y, La, Ce) and lanthanide–titanium citrates (CA) and tartrates (TA) have been studied. The complexes have been prepared in ethylene glycol medium at conditions modeling those of the polymerized-complex method applied for Ln2Ti2O7 preparation. Special attention has been paid to the chemical nature of the bimetallic products as well as to the factors influencing the deprotonation of the alcoholic OH groups of the acidic ligands. The results contribute to further elucidation of the complexation and thermal decomposition processes involved in the polymerized-complex method.Key words: inorganic compounds, sol–gel chemistry, infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA).
Key Engineering Materials, 2004
... [10] D. Todorovsky, M. Getsova and M. Milanova: Synth. Reactivity in Inorg. Metal-Org. Chem. ... more ... [10] D. Todorovsky, M. Getsova and M. Milanova: Synth. Reactivity in Inorg. Metal-Org. Chem. Vol. 33 (2003), p. 223. [11] D. Todorovsky, N. Petrova: Ann. Univ. Sofia Fac. Chim. Vol. 96 (2003) (in press). [12] M. Getsova, D. Todorovsky, I. Wawer and V. Enchev (to be publiched). ...
Materials Letters, 2004
La-, Ti-and La-Ti-citrates, prepared in ethylene glycol medium (at conditions similar to those us... more La-, Ti-and La-Ti-citrates, prepared in ethylene glycol medium (at conditions similar to those used in the polymerized complex method) and isolated as solid substances, have been studied by 13 C-solid state NMR analysis, XPS, SEM and EDAX. The obtained results, together with data from elemental, thermogravimetric, IR, 13 C-and 1 H-NMR (in solution) analysis, give evidence for the mixed-metal nature of the bimetallic citric complex and permit a hypothetical structure to be proposed.
Synthesis and Reactivity in Inorganic and Metal-organic Chemistry, 2003
The composition, IR, C and H NMR spectral characteristics and thermochemical behavior of La‐, Ti‐... more The composition, IR, C and H NMR spectral characteristics and thermochemical behavior of La‐, Ti‐ and bimetallic La‐Ti‐tartrates (potential precursors of La2Ti2O7), obtained in ethylene glycol, were studied. The comparison of their main characteristics with those of the analogous citric complexes contributes to the elucidation of the processes involved in the complexation and thermal decomposition of such complexes. The bimetallic
Monatshefte für Chemie - Chemical Monthly, 2007
Cerium(III=IV) and Ce(IV)-Ti(IV) citric complexes were synthesized in ethylene glycol medium unde... more Cerium(III=IV) and Ce(IV)-Ti(IV) citric complexes were synthesized in ethylene glycol medium under conditions similar to those of the polymerized complex method (PCM). Solution phase 1 H, 13 C NMR, solid state 13 C CP MAS NMR and IR spectroscopy, and X-ray powder diffractometry were used to characterize the composition and structure of the synthesized products. Thermal decomposition of the isolated complexes was studied and a scheme of the processes taking place is proposed. Complexes of Ce(III) can be prepared at low temperature (40 C), only. In the presence of Ti(IV) ions, the oxidation takes place even at this temperature. A mixed-metal nature of the Ce(IV)-Ti(IV) complexes is established. The comparison between their composition and the one of analogous lanthanide(III)-Ti(IV) citrates contributes to the elucidation of the complexation process mechanism in the case of the PCM application. The increased charge of the complexation agent in the Ce 4þ-Ti 4þ complex (in comparison with Ln 3þ-Ti 4þ citrates) is ''compensated'' by the increase of the relative number of the ligands with deprotonated OH group.
Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors... more Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors for YFeO 3 and Y 3 Fe 5 O 12 thin films preparation, have been synthesized in ethylene glycol medium. The compositions, IR, 1 H and 13 C NMR spectral characteristics of the isolated solid complexes have been studied. Their chemical nature and the peculiarities of the complexation process in the system Y III-Fe IIIcitric acid-ethylene glycol = 1 : 1 : 8.5 : 35 have been studied and compared with those of the earlier studied lanthanide(III or IV)-titanium(IV) citric acid complexes, prepared under the same conditions. The mixed-metal nature of the obtained complexes has been shown. In contrast to the analogous lanthanide-titanium system, no deprotonation of the alcoholic OH groups of citric ligands takes place in the course of the formation of Y-Fe complexes.
The paper addresses the thermal decomposition of La-, Ti- and bimetallic La-Ti-non-crystalline ci... more The paper addresses the thermal decomposition of La-, Ti- and bimetallic La-Ti-non-crystalline citric complexes, prepared in ethylene glycol medium. The latter complex is the starting material for the effective ferroelectric La2Ti2O7 preparation by the polymerized complex method. Based on thermogravimetric analysis (DTG, DTA and TG) and identification of some of the intermediates (by elemental analysis, NMR and IR spectroscopy and
ChemInform, 2005
For Abstract see ChemInform Abstract in Full Text.
Zeitschrift für anorganische und allgemeine Chemie, 2000
Yttrium, titanium, and yttrium-titanium citrate complexes are synthesized in ethylene glycol medi... more Yttrium, titanium, and yttrium-titanium citrate complexes are synthesized in ethylene glycol medium at conditions similar to those used when the polymerized complex method (a version of the sol-gel technology) is applied. The composition and IR, 1H and 13C NMR spectral characteristics of the isolated solid state complexes are studied. Proofs of the mixed metal nature of the bimetallic complexes are reported. The conditions of deprotonation of the alcoholic OH group of the citrate ligands are considered. Darstellung und Charakterisierung von Yttrium–Titan-Citratkomplexen Yttrium-, Titan- und Yttrium–Titan-Citratkomplexe wurden in Ethylenglykol unter ahnlichen Bedingungen wie bei der Komplexpolymerisation (Sol-Gel-Technik) synthetisiert. Die Zusammensetzung sowie IR-, 1H- und 13C-NMR spektroskopischen Charakteristika der isolierten festen Komplexe wurden bestimmt bzw. untersucht. Hinweise auf die gemischtmetallische Natur der Bimetallkomplexe werden angegeben. Die Bedingungen der Deprotonierung der alkoholischen OH-Gruppe der Citratliganden werden diskutiert.
Depleted U 3 O 8 was mechanically activated in suspension with tributyl phosphate (TBP), trioctyl... more Depleted U 3 O 8 was mechanically activated in suspension with tributyl phosphate (TBP), trioctylamine (TOA) and ethylenglycolmonomethylether (EGME) in planetary ball mill with stainless steel vessels and balls. X-ray diffractograms and IR spectra of the activated solid samples were taken. The radioactivities of 238 U and 234 Th in the leaching solutions were determined by α/β liquid scintillation spectrometry. The reduction degree of the oxide, the mean crystallite size of U 3 O 8 and U 3 O 7 and the leaching of 238 U and 234 Th as a result of the mechanoactivation were determined. Higher degree of 238 U and 234 Th leaching was achieved when mechanoactivation with TBP was performed. No leaching of 238 U daughter product ( 234 Th) proceeded at mechanoactivation with TOA and EGME. The role of the solvents complexation ability, milling induced increase of crystal defect concentration and UO 2 – ThO 2 solid solution formation is discussed. Further studies have to be made to elucidate t...
Ru(II)-tris (4,7-diphenyl-1,10-phenanthroline) dichloride immobilized in matrices from sol-gel pr... more Ru(II)-tris (4,7-diphenyl-1,10-phenanthroline) dichloride immobilized in matrices from sol-gel produced SiO2, SiO2-citric acid/ethylene glycol polyester hybrid or poly (methylmetacrylate) is explored as a sensor for determination of dissolved oxygen in white and red wines. The significant overlapping of the 612 nm spectral bands of the oxygensensitive chromophore with the analyzed products band imposes the necessity of accounting for the impact of the latter in the analysis. The SiO2-based composite is rather sensitive to the prolonged action of wine causing a disturbance of the linearity of the Stren-Volmer dependence and significant decrease of the respective constant.
Bulgarian Chemical Communications, 1996
Etude du comportement au recuit de 35 S produit dans des cristaux mixtes AlCl 3 −FeCl 3 irradies ... more Etude du comportement au recuit de 35 S produit dans des cristaux mixtes AlCl 3 −FeCl 3 irradies dans une pile: l'etat chimique de 35 S est defini par la prehistoire de la cible et la concentration en Fe
Bulgarian Chemical Communications, 1996
Etude des retentions des orthophosphates et des phosphates totaux dans les orthophosphates alcali... more Etude des retentions des orthophosphates et des phosphates totaux dans les orthophosphates alcalins irradies par les neutrons et contenant differentes quantites d'eau de cristallisation
Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors... more Yttrium-iron(III) citric acid complexes with mole ratio Y : Fe = 1 or 3 : 5, potential precursors for YFeO 3 and Y 3 Fe 5 O 1 2 thin films preparation, have been synthesized in ethylene glycol medium. The compositions, IR, 1 H and 1 3 C NMR spectral characteristics of the isolated solid complexes have been studied. Their chemical nature and the peculiarities of the complexation process in the system Y I I I -Fe I I I -citric acid-ethylene glycol 1 : 1 : 8.5 : 35 have been studied and compared with those of the earlier studied lanthanide(III or IV)-titanium(IV) citric acid complexes, prepared under the same conditions. The mixed-metal nature of the obtained complexes has been shown. In contrast to the analogous lanthanide-titanium system, no deprotonation of the alcoholic OH groups of citric ligands takes place in the course of the formation of Y-Fe complexes.
ChemInform, 2001
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.