The mechanism of redox-conversions of tungstovanadophosphoric heteropolyanions

Dioxygen in Polyoxometalate Mediated Reactions

“…It was also suggested that the reoxidation of the polyoxometalate was through an inner sphere reaction of H 7 PV 2 IV Mo 10 O 40 with O 2 via formation of a μ-peroxo intermediate followed by formation of water. It should be noted that there were several previous reports on the kinetics of oxidation of reduced polyoxometalates of these types in general support of the idea of a four electron oxidation of the reduced vanadium containing polyoxometalate by O 2 but no spectroscopic support for exactly which reactions may be occurring in solution. , Supported catalysts on fluorapatite, and other carbon supports, , have also been reported for this reaction, as has the aromatization of 1-4-dihydropyridines …”

Present General Status of Understanding of Heteropoly Electrolytes and a Tracing of Some Major Highlights in the History of Their Elucidation

“…The largest number of Maksimovskaya's papers (usually with M. A. Fedotov) involve multinuclear NMR ( 17 O, 31 P, 51 V, 183 W, 29 Si, 71 Ga) elucidating structure, thermally induced changes, and status in solution. − papers report rates of 17 O exchange. − A dozen papers are devoted to syntheses of heteropoly compounds, − including crystalline salts of [Se 2 Mo 2 V 6 O 28 ] 6- , [MoV 9 O 28 ] 5- , [VMo 5 O 19 ] 3- , and H 6 [P 2 W 21 O 71 ] − Reactions of certain heteropoly species were described. − Some papers are based on EPR studies. − Four papers concern heteropoly blues. 1178, 1180-1182 Five studies of thermal decomposition and thermolysis were reported − and another five appeared on the status of various heteropoly species in aqueous solutions. − There were two papers on oxidations by heteropoly ...…”

“…[1164][1165][1166][1167][1168][1169][1170] Reactions of certain heteropoly species were described. [1171][1172][1173][1174][1175][1176] Some papers are based on EPR studies. [1177][1178][1179] Four papers concern heteropoly blues.…”

Synthesis and spectral properties of titanium(iv) polynuclear hydroxo complexes stabilized in solution by the [PW11O39]7− heteropolyanion

“…It is known that heteropolyanions (HPA) of the Keggin "s type in which one or more Mo or W atoms are replaced by transition metal ions M can catalyze oxidation reactions, z-3 The reactivity of the heteropolyanion depends on the number and the arrangement of ions M. 4.s In this connection, preparation of M-containing heteropolyanions of different compositions and different structures is of interest.…”

“…Thus, the formation of polynuclear Vre hydroxo complexes may account for the high catalytic activities of [PW I iV040] 5-and [PWtoV2040] 7-in oxidation of Vre ions by 02, whereas the heteropolyanions in themselves are not oxidized by oxygen. 4 To date, heteropolycomplexes in which one or several Tire ions are involved in the HPA framework (for example, [PWtiTi04015-, 7 [PWloTi204017-, s and [Ge2Ti6W18077]14-) have been prepared and structurally characterized. 9 In this work, we synthesized polynuclear [PWlt] ratio (n) of (I~12) : l and a concentration of 0.01--0.03 or 0.2 tool L -I were prepared from dilute (series I) or concentrated (series II) solutions of NaTPWtlO39 and the corresponding amounts of Ti2(SO4) 3 in H2SO 4 followed by oxidation of blue solutions obtained by oxygen at -25 *C. A saturated solution of Na2CO 3 was added with stirring to colorless solutions of Ti TM heteropolycomplexes to pH I--3.…”