The violet polycrystalline (NH4)5[(VO)6(CO3)4(OH)9]·10H2O(NVCO) was simply sy nthesized by solution reaction using V2O5, HCl, N2H4·2HCl and NH4HCO3 as the st arting materials. The results of TGA and DTA of N...The violet polycrystalline (NH4)5[(VO)6(CO3)4(OH)9]·10H2O(NVCO) was simply sy nthesized by solution reaction using V2O5, HCl, N2H4·2HCl and NH4HCO3 as the st arting materials. The results of TGA and DTA of NVCO under H2(99.999%) atmosphe re show that V2O3 forms at 620℃. The data of TG/DTG and DTA of NVCO under N2(99 .999%) atmosphere indicate that VO2 forms at 367℃and crystallizes at 390℃. In air atmosphere, the TG/DTG and DTA of NVCO show that V2O5 forms at 354℃, cryst allizes at 366℃and melts at 664℃. The three thermolysis processes of NVCO show that a large amount of H2O, CO2 and NH3 gases fast releases during the thermoly sis of NVCO, causing that the particles of the materials split and atomize stron gly, thus to obtain V2O3, VO2 and V2O5 nano-powders finally. According to the a bove of thermoanalytical results, V2O3, VO2 and V2O5 powders were prepared respe ctively under H2, N2 and oxygen in a tube furnace. Chemical analysis and XRD exp eriments of the powders identify that pure V2O3 is obtained at 800℃for 0.5h und er H2 atmosphere; crystalline VO2 is obtained at 480℃for 0.5h in N2; amorphous VO2 is obtained at 350℃for 20min under N2 atmosphere, this has been first repor ted to prepare amorphous VO2 powder so far; pure V2O5 is obtained at 400℃for 10 min under oxygen. From the micrographs of the powders, the particle size of the V2O3, the crystalline VO2 or the V2O5 powders is 35nm, 24nm or < 40nm, respectiv ely. Above-mentioned results prove that NVCO is a good precursor for preparatio n of pure V2O3, VO2 and V2O5 nano-powders under mild conditions.展开更多
Five oxovanadium(Ⅳ) dinuclear complexes described by the overall formula [(VO)2(IA)L2]-SO4, where IA represents the dianion of iodanilic acid and L denotes 2,2'-bipyridine (bpy) ; 4,4'-dimethyl-2,2'-bipyr...Five oxovanadium(Ⅳ) dinuclear complexes described by the overall formula [(VO)2(IA)L2]-SO4, where IA represents the dianion of iodanilic acid and L denotes 2,2'-bipyridine (bpy) ; 4,4'-dimethyl-2,2'-bipyridine (Me2-bpy); 1,10-phenanthroline (phen); 4,7-diphenyl-1, 10-phenanthroline (Ph2-phen) and 5-nitro-l, 10-phenanthroline (NO2-phen) , have been synthesized and characterized by elemental analyses, molar conductivity and room-temperature magnetic moment measurements, IR and electronic spectral studies. It is proposed that these complexes have IA-bridged structures and consist of two oxovanadium(Ⅳ) ions each in a square- pyramidal environment. The complexes [ ( VO)2 (IA) (bpy )2 ] SO4 (1) and [ ( VO )2 ( IA) ( phen)2 ] -SO4 (2) were further characterized by variable temperature (4.2-300 K) magnetic susceptibility measurements and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method, giving the exchange integral J = -2.15 cm-1 for 1 and J = - 9.88 cm-1 for 2. This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two VO2+ ions within each molecule.展开更多
Six novel oxovanadium(IV) binuclear complexes have been synthesized and characterized,namely,[(VO)2(CA)La]SO4 [L denotes 5-methyl-l,10-phenanthroline (Me-phen);2,9-dimethyl-1,10-phenanthroline (Me2-phen); 5-chloro-l,1...Six novel oxovanadium(IV) binuclear complexes have been synthesized and characterized,namely,[(VO)2(CA)La]SO4 [L denotes 5-methyl-l,10-phenanthroline (Me-phen);2,9-dimethyl-1,10-phenanthroline (Me2-phen); 5-chloro-l,10-phenanthroline (Cl-phen); diaminoethane (en); 1,3-diaminopropane (pn) and 1,2-diaminopropane (ap) respectively.],where CA represents the dianion of chloranilic acid.Based on elemental analyses,molar conductivity and room temperature magnetic moment measurements,IR and electronic spectral studies,it is proposed that these complexes have CA-bridged structures and consist of two vanadium(IV) ions in a square-pyramidal environment.The complexes [(VO)2(CA)(Me-phen)2]SO4 (1) and [(VO)2(CA)(Me2-phen)2]SO4 (2) were characterized by variable temperature magnetic susceptibility measurements (4~300 K) and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method,giving the exchange integral J=-15.8 cm-1 for 1 and J=-10.6 cm-1 for 2.This result indicates that t展开更多
文摘The violet polycrystalline (NH4)5[(VO)6(CO3)4(OH)9]·10H2O(NVCO) was simply sy nthesized by solution reaction using V2O5, HCl, N2H4·2HCl and NH4HCO3 as the st arting materials. The results of TGA and DTA of NVCO under H2(99.999%) atmosphe re show that V2O3 forms at 620℃. The data of TG/DTG and DTA of NVCO under N2(99 .999%) atmosphere indicate that VO2 forms at 367℃and crystallizes at 390℃. In air atmosphere, the TG/DTG and DTA of NVCO show that V2O5 forms at 354℃, cryst allizes at 366℃and melts at 664℃. The three thermolysis processes of NVCO show that a large amount of H2O, CO2 and NH3 gases fast releases during the thermoly sis of NVCO, causing that the particles of the materials split and atomize stron gly, thus to obtain V2O3, VO2 and V2O5 nano-powders finally. According to the a bove of thermoanalytical results, V2O3, VO2 and V2O5 powders were prepared respe ctively under H2, N2 and oxygen in a tube furnace. Chemical analysis and XRD exp eriments of the powders identify that pure V2O3 is obtained at 800℃for 0.5h und er H2 atmosphere; crystalline VO2 is obtained at 480℃for 0.5h in N2; amorphous VO2 is obtained at 350℃for 20min under N2 atmosphere, this has been first repor ted to prepare amorphous VO2 powder so far; pure V2O5 is obtained at 400℃for 10 min under oxygen. From the micrographs of the powders, the particle size of the V2O3, the crystalline VO2 or the V2O5 powders is 35nm, 24nm or < 40nm, respectiv ely. Above-mentioned results prove that NVCO is a good precursor for preparatio n of pure V2O3, VO2 and V2O5 nano-powders under mild conditions.
基金Natural Science Foundation of Shandong Province (No. Y97-D17076)National Natural Science Foundation of China (No. 29631040).
文摘Five oxovanadium(Ⅳ) dinuclear complexes described by the overall formula [(VO)2(IA)L2]-SO4, where IA represents the dianion of iodanilic acid and L denotes 2,2'-bipyridine (bpy) ; 4,4'-dimethyl-2,2'-bipyridine (Me2-bpy); 1,10-phenanthroline (phen); 4,7-diphenyl-1, 10-phenanthroline (Ph2-phen) and 5-nitro-l, 10-phenanthroline (NO2-phen) , have been synthesized and characterized by elemental analyses, molar conductivity and room-temperature magnetic moment measurements, IR and electronic spectral studies. It is proposed that these complexes have IA-bridged structures and consist of two oxovanadium(Ⅳ) ions each in a square- pyramidal environment. The complexes [ ( VO)2 (IA) (bpy )2 ] SO4 (1) and [ ( VO )2 ( IA) ( phen)2 ] -SO4 (2) were further characterized by variable temperature (4.2-300 K) magnetic susceptibility measurements and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method, giving the exchange integral J = -2.15 cm-1 for 1 and J = - 9.88 cm-1 for 2. This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two VO2+ ions within each molecule.
基金Project supported by the Natural Science Foundation of Shandong Provincethe National Natural Science Foundation of China
文摘Six novel oxovanadium(IV) binuclear complexes have been synthesized and characterized,namely,[(VO)2(CA)La]SO4 [L denotes 5-methyl-l,10-phenanthroline (Me-phen);2,9-dimethyl-1,10-phenanthroline (Me2-phen); 5-chloro-l,10-phenanthroline (Cl-phen); diaminoethane (en); 1,3-diaminopropane (pn) and 1,2-diaminopropane (ap) respectively.],where CA represents the dianion of chloranilic acid.Based on elemental analyses,molar conductivity and room temperature magnetic moment measurements,IR and electronic spectral studies,it is proposed that these complexes have CA-bridged structures and consist of two vanadium(IV) ions in a square-pyramidal environment.The complexes [(VO)2(CA)(Me-phen)2]SO4 (1) and [(VO)2(CA)(Me2-phen)2]SO4 (2) were characterized by variable temperature magnetic susceptibility measurements (4~300 K) and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method,giving the exchange integral J=-15.8 cm-1 for 1 and J=-10.6 cm-1 for 2.This result indicates that t
