New Structural Features in Tetranuclear Iron Carbonyl Thiocarbonyls: Exotriangular Iron Atoms and Six‐Electron‐Donating Thiocarbonyl Groups Bridging Four Iron Atoms

Bridging selenocarbonyl ligands: an open and shut case

The novel platinum bis(isoselenocarbonyl) complex [Pt{SeCW(CO)₂(Tp*)}₂] is capable of opening both μ:σ–μ-CSe bridges to allow addition of nucleophilic (CNR: R = ^tBu, C₆H₂Me₃) reagents to platinum by varying the selenocarbonyl bridging mode.

Isoselenocarbonyl complexes

The salt elimination reactions of [NEt₄][Mo(CSe)(CO)₂(Tp*)] ([NEt₄][2], Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with a range of metal halide complexes (ClML_n) have been investigated as a possible route to isoselenocarbonyl complexes [Mo(CSeML_n)(CO)₂(Tp*)].

Quantum chemical studies of redox properties and conformational changes of a four-center iron CO2 reduction electrocatalyst

Two calculated structures of the [Fe₄N(CO)12]^3– CO₂ reduction electrocatalyst in its twice reduced state connected by a CO dissociation pathway are studied.

The CO₂ reduction electrocatalyst [Fe₄N(CO)₁₂]^– (abbrev. 1^–) reduces CO₂ to HCO₂^– in a two-electron, one-proton catalytic cycle. Here, we employ ab initio calculations to estimate the first two redox potentials of 1^– and explore the pathway of a side reaction involving CO dissociation from 1^3–. Using the BP86 density functional approximation, the redox potentials were computed with a root mean squared error of 0.15 V with respect to experimental data. High temperature Born–Oppenheimer molecular dynamics was employed to discover a reaction pathway of CO dissociation from 1^3– with a reaction energy of +10.6 kcal mol^–1 and an activation energy of 18.8 kcal mol^–1; including harmonic free energy terms, this yields ΔG_sep = 1.4 kcal mol^–1 for fully separated species and ΔG^‡ = +17.4 kcal mol^–1, indicating CO dissociation is energetically accessible at ambient conditions. The analogous dissociation pathway from 1^2– has a reaction energy of 22.1 kcal mol^–1 and an activation energy of 22.4 kcal mol^–1 (ΔG_sep = 12.8 kcal mol^–1, ΔG^‡ = +18.1 kcal mol^–1). Our computed harmonic vibrational analysis of [Fe₄N(CO)₁₁]^3– or 2^3– reveals a distinct CO-stretching peak red-shifted from the main CO-stretching band, pointing to a possible vibrational signature of dissociation. Multi-reference CASSCF calculations are used to check the assumptions of the density functional approximations that were used to obtain the majority of the results.