Reactivity of Cr⁺(⁶S,⁴D), Mn⁺(⁷S,⁵S), and Fe⁺(⁶D,⁴F): Reaction of Cr⁺, Mn⁺, and Fe⁺ with Water

Abstract

The study of the reaction of water with the first-row transition-metal ions is continued in this work. Here we report the study of the reaction of water with the middle (Cr+, Mn+, and Fe+) first-row transition-metal cations in both high- and low-spin states. In agreement with experimental observations, the oxides are predicted to be more reactive than the metal ions, and no exothermic products are observed. Formation of endothermic products is examined. An in-depth analysis of the reaction paths leading to the observed products is given, including various minima, and several important transition states. All results have been compared with existing experimental and theoretical data, and our earlier works covering the (Sc+, Ti+, V+) + H2O reactions to observe existent trends for the early first-row transition-metal ions. The MO+ + H2 energy relative to M+ + H2O increases through the series from left to right. Additionally, the Fe+ case is seen to be significantly different from the entire Sc+−Mn+ series because both its low- and high-spin cases involve paired electrons, and Mn+ shows some differences because of the complete half-filling of its valence shell in the high-spin case.

Density Functional Theory in Transition-Metal Chemistry: Relative Energies of Low-Lying States of Iron Compounds and the Effect of Spatial Symmetry Breaking

“…Our results for relative state energies ∆E, equilibrium internuclear distance r e , and harmonic vibrational frequencies ω e are given in Tables 4-9, where they are also compared to previous theoretical 15,[87][88][89][90][91][92] and experimental [93][94][95] results. A point of special interest is the comparison to DFT+U 19,96 calculations, 15,92 in particular PBE+U, where +U denotes a Hubbard-like 96 correction, carried out with a plane wave (PW) basis.…”

“…69,86 Relativistic effects should be included for quantitative comparison with experiment, but one of our main goals here was to compare to previous theoretical calculations, which all neglected relativistic effects. 15,[87][88][89][90][91][92] It should also be noted that in NWChem, while analytical gradients are available for open-shell DFT, analytical Hessians are not. Therefore, the DFT harmonic vibrational frequencies ω e were calculated by numerical central differences.…”

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

“…22,23 TiO 2 , ZrO 2 , and HfO 2 oxides have also been utilized to catalyze the aromatization of C 6+ alkanes. 20 While chemical reactions of the bare transition metal oxide cations with H 2 have received a significant interest, [24][25][26][27][28][29][30][31][32][33][34][35][36][37] neutral metal oxides have gained much less attention. [38][39][40][41][42][43][44][45][46][47][48][49][50] Recently Zhou et al 51 have reported a combined experimental and theoretical study on the hydrogenation reactions by group V metal dioxides using matrix isolation spectroscopy.…”

Photodissociation and photochemistry of V+(H2O)n, n = 1–4, in the 360–680 nm region

“…Broad-band photolysis with a high-pressure mercury arc lamp yields the bare oxide VO [21]. The potential energy surfaces of water activation by first-row transition metal ions were calculated in a series of papers by Ugalde and coworkers [22][23][24][25][26], showing that the case of Fe + is a typical example of two-state-reactivity [27]. For V + , elimination of H 2 involves a curve crossing from the quintet to the triplet surface [24].…”