Transition metal cations transfer

Simplest examples are prepared by the cyclic oligomerization of ethylene oxide. They act as complexing agents which solubilize alkali metal ions in non-polar solvents, complex alkaline earth cations, transition metal cations and ammonium cations, e.g. 12—crown —4 is specific for the lithium cation. Used in phase-transfer chemistry. ... 

As alluded to in Section 5.5.5, the transition metal monoxides with the rock-salt strucmre are the archtypical examples of correlated systems. Of these oxides, only TiO is metallic. The others, NiO, CoO, MnO, FeO, and VO, are all insulating, despite the fact that the Fermi level falls within a partially filled band (in the independent electron picture). Direct electron transfer between two of the transition metal cations (in the rock-salt strucmre, d d interactions are important owing to the proximity of the cations), say, manganese, is equivalent to the disproportionation reaction ... 

Zeolite catalysts incorporated or encapsulated with transition metal cations such as Mo, or Ti into the frameworks or cavities of various microporous and mesoporous molecular sieves were synthesized by a hydrothermal synthesis method. A combination of various spectroscopic techniques and analyses of the photocatalytic reaction products has revealed that these transition metal cations constitute highly dispersed tetrahedrally coordinated oxide species which enable the zeolite catalysts to act as efficient and effective photocatalysts for the various reactions such as the decomposition of NO into N2 and O2 and the reduction of CO2 with H2O into CH3OH and CH4. Investigations on the photochemical reactivities of these oxide species with reactant molecules such as NOx, hydrocarbonds, CO2 and H2O showed that the charge transfer excited triplet state of the oxides, i.e., (Mo - O ), - O ), and (Ti - O ), plays a significant role in the photocatalytic reactions. Thus, the present results have clearly demonstrated the unique and high photocatalytic reactivities of various microporous and mesoporous zeolitic materials incorporated with Mo, V, or Ti oxide species as well as the close relationship between the local structures of these transition metal oxide species and their photocatalytic reactivities. 

Transition metal cations exhibit acidic behavior in solntion the impact of a positively charged metal ion on its bound water molecules is related to the inductive effect in oxyacids. The O—H bonds of water bound to transition metal ions are weakened since bonding electron density is drawn towards the metal. For example, aqueous Fe is acidic, with yellow or brown iron species formed by reactions where proton transfer occurs from solvated water molecules resulting in bound hydroxide... 

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