Characterization and reactivity of oxygen-centred radicals over transition metal oxide clusters

Abstract

We introduce chemical structures and reactivity of oxygen-centred radicals (O(-)˙) over transition metal oxide (TMO) clusters based on mass spectrometric and density functional theory studies. Two main issues will be discussed: (1) the compositions of TMO clusters that have the bonding characteristics of (or contain) the O(-)˙ radicals; and (2) the dependences (cluster structures, sizes, charge states, metal types, etc.) of the chemical reactivity and selectivity for the O(-)˙ radicals over TMO clusters. One of the goals of cluster chemistry is to understand the elementary reactions involved with complex heterogeneous catalysis. The study of the O(-)˙ containing TMO clusters permits rather detailed descriptions for how mono-nuclear oxygen-centred radicals may exist and react with small molecules over TMO based catalysts.

Stable Stoichiometry of Gas-Phase Cerium Oxide Cluster Ions and Their Reactions with CO

“…The radicals can play a definitive role in the reactions of clusters, which will be discussed later. CenO2n + species are considered to hold an oxygen-centered radical, 6,16,17 whereas CenO2n−1 + have one unpaired electron located in Ce 4f orbitals. 18 For CenO2n+1 + and CenO2n+2 + , the spin distribution remains 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 side-on bound with the Ce center in the most stable structure.…”

Gas phase chemistry of neutral metal clusters: Distribution, reactivity and catalysis

“…After more than two decades, many examples of catalytic cycles facilitated by metal atoms [42][43][44][45], metal clusters [17,46,47], and metal oxide clusters [5,[48][49][50][51] have been demonstrated. Several excellent reviews are available in the literature [30,[52][53][54][55].…”

How a Quantum Chemical Topology Analysis Enables Prediction of Electron Density Transfers in Chemical Reactions. The Degenerated Cope Rearrangement of Semibullvalene

“…13 For example, TiO 2 is one of the most technologically important oxide materials widely studied as a prototypical transition metal oxide because of its rather simple electronic structure. [14][15][16] Thanks to its photocatalytic properties, TiO 2 has been utilized in the production of hydrogen gas by photoelectrolysis of water 17,18 and conversion of CO 2 in aqueous medium to methanol.…”