More Like this

1. Ligand field effects on the ground and excited states of reactive FeO ²⁺ species

   https://doi.org/10.1039/c8cp05372c  

   Kirkland, Justin K.; Khan, Shahriar N.; Casale, Bryan; Miliordos, Evangelos; Vogiatzis, Konstantinos D. (November 2018, Physical Chemistry Chemical Physics)

   High-valent Fe( iv )-oxo species have been found to be key oxidizing intermediates in the mechanisms of mononuclear iron heme and non-heme enzymes that can functionalize strong C–H bonds. Biomimetic Fe( iv )-oxo molecular complexes have been successfully synthesized and characterized, but their catalytic reactivity is typically lower than that of the enzymatic analogues. The C–H activation step proceeds through two competitive mechanisms, named σ- and π-channels. We have performed high-level wave function theory calculations on bare FeO 2+ and a series of non-heme Fe( iv )-oxo model complexes in order to elucidate the electronic properties and the ligand field effects on those channels. Our results suggest that a coordination environment formed by a weak field gives access to both competitive channels, yielding more reactive Fe( iv )-oxo sites. In contrast, a strong ligand environment stabilizes only the σ-channel. Our concluding remarks will aid the derivation of new structure–reactivity descriptors that can contribute to the development of the next generation of functional catalysts. 

   more » « less
2. Insertion of CO ₂ Mediated by a (Xantphos)Ni ^I –Alkyl Species

   https://doi.org/10.1002/anie.201906005  

   Diccianni, Justin B.; Hu, Chunhua T.; Diao, Tianning (August 2019, Angewandte Chemie International Edition)

   Abstract The incorporation of CO₂into organometallic and organic molecules represents a sustainable way to prepare carboxylates. The mechanism of reductive carboxylation of alkyl halides has been proposed to proceed through the reduction of Ni^IIto Ni^Iby either Zn or Mn, followed by CO₂insertion into Ni^I‐alkyl species. No experimental evidence has been previously established to support the two proposed steps. Demonstrated herein is that the direct reduction of (tBu‐Xantphos)Ni^IIBr₂by Zn affords Ni^Ispecies. (tBu‐Xantphos)Ni^I‐Me and (tBu‐Xantphos)Ni^I‐Et complexes undergo fast insertion of CO₂at 22 °C. The substantially faster rate, relative to that of Ni^IIcomplexes, serves as the long‐sought‐after experimental support for the proposed mechanisms of Ni‐catalyzed carboxylation reactions. 

   more » « less
3. Effect of Metal Ions on Oxidation of Micropollutants by Ferrate(VI): Enhancing Role of Fe ^IV Species

   https://doi.org/10.1021/acs.est.0c04674  

   Zhang, Xianbing; Feng, Mingbao; Luo, Cong; Nesnas, Nasri; Huang, Ching-Hua; Sharma, Virender K. (January 2021, Environmental Science & Technology)

   null (Ed.)
4. Distribution of Aluminum Species in Zeolite Catalysts: ²⁷ Al NMR of Framework, Partially-Coordinated Framework, and Non-Framework Moieties

   https://doi.org/10.1021/jacs.1c02361  

   Chen, Kuizhi; Gan, Zhehong; Horstmeier, Sarah; White, Jeffery L. (May 2021, Journal of the American Chemical Society)

   null (Ed.)
5. Phosphorescence in Mn ⁴⁺ -Doped R ⁺ / R ²⁺ Germanates ( R ⁺ = Na ⁺ or K ⁺ , R ²⁺ = Sr ²⁺ )

   https://doi.org/10.1021/acs.inorgchem.2c01364  

   Novikov, Sergei A.; Lu, Yimin; Zhang, Weiguo; Halasyamani, P. Shiv; Hariyani, Shruti; Brgoch, Jakoah; Klepov, Vladislav V.; zur Loye, Hans-Conrad; Mozharivskyj, Yurij (June 2022, Inorganic Chemistry)