Ligand Field Effects on the Ground and Excited States of the Catalytically Active FeO2+ Species

<p>We have performed high-level wave function theory calculations on bare FeO2+ 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. On the contrary, a strong ligand environment stabilizes only the σ-channel. Our concluding remarks will aid on the derivation of new structure-reactivity descriptors that can contribute on the development of the next generation of functional catalysts.</p>

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Ligand field effects on the ground and excited states of reactive FeO2+ species

Physical Chemistry Chemical Physics ◽

10.1039/c8cp05372c ◽

2018 ◽

Vol 20 (45) ◽

pp. 28786-28795 ◽

Cited By ~ 14

Author(s):

Justin K. Kirkland ◽

Shahriar N. Khan ◽

Bryan Casale ◽

Evangelos Miliordos ◽

Konstantinos D. Vogiatzis

Keyword(s):

Iron Oxide ◽

Quantum Chemical Calculations ◽

Excited States ◽

Quantum Chemical ◽

Ligand Field ◽

Reactive Iron ◽

Field Effects ◽

Ligand Fields

Multiconfigurational quantum chemical calculations on bare and representative ligated iron oxide dicationic species suggest that weak ligand fields promote more reactive channels, whereas strong ligand fields stabilize the less reactive iron-oxo structure.

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Jahn–Teller coupling and the influence of strain in Tg and Eg ground and excited states – A ligand field and DFT study on halide MIIIX6 model complexes [M=TiIII–CuIII; X=F−, Cl−]

Coordination Chemistry Reviews ◽

10.1016/j.ccr.2010.04.015 ◽

2010 ◽

Vol 254 (23-24) ◽

pp. 2703-2754 ◽

Cited By ~ 22

Author(s):

D. Reinen ◽

M. Atanasov ◽

P. Köhler ◽

D. Babel

Keyword(s):

Excited States ◽

Dft Study ◽

Ligand Field ◽

Model Complexes ◽

Jahn Teller

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The Character of Low-Lying Excited States of Mixed-Ligand Metal Carbonyls. TD-DFT and CASSCF/CASPT2 Study of [W(CO)4L] (L = ethylenediamine, N,N'-dialkyl-1,4-diazabutadiene) and [W(CO)5L] (L = pyridine, 4-cyanopyridine)

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20030089 ◽

2003 ◽

Vol 68 (1) ◽

pp. 89-104 ◽

Cited By ~ 6

Author(s):

Stanislav Záliš ◽

Antonín Vlček ◽

Chantal Daniel

Keyword(s):

Excited States ◽

Substitution Effect ◽

Electronic Transitions ◽

Ligand Field ◽

Metal Carbonyls ◽

Electron Density Redistribution ◽

Time Resolved ◽

Model Complex ◽

Td Dft ◽

Time Resolved Infrared Spectroscopy

This contribution presents the results of the TD-DFT and CASSCF/CASPT2 calculations on [W(CO)4(MeDAB)] (MeDAB = N,N'-dimethyl-1,4-diazabutadiene), [W(CO)4(en)] (en = ethylenediamine), [W(CO)5(py)] (py = pyridine) and [W(CO)5(CNpy)] (CNpy = 4-cyanopyridine) complexes. Contrary to the textbook interpretation, calculations on the model complex [W(CO)4(MeDAB)] and [W(CO)5(CNpy)] show that the lowest W→MeDAB and W→CNpy MLCT excited states are immediately followed in energy by several W→CO MLCT states, instead of ligand-field (LF) states. The lowest-lying excited states of [W(CO)4(en)] system were characterized as W(COeq)2→COax CT excitations, which involve a remarkable electron density redistribution between axial and equatorial CO ligands. [W(CO)5(py)] possesses closely-lying W→CO and W→py MLCT excited states. The calculated energies of these states are sensitive to the computational methodology used and can be easily influenced by a substitution effect. The calculated shifts of [W(CO)4(en)] stretching CO frequencies due to excitation are in agreement with picosecond time-resolved infrared spectroscopy experiments and confirm the occurrence of low-lying M→CO MLCT transitions. No LF electronic transitions were found for either of the complexes studied in the region up to 4 eV.

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Correlating Axial and Equatorial Ligand Field Effects to the Single-Molecule Magnet Performances of a Family of Dysprosium Bis-Methanediide Complexes

Chemical Science ◽

10.1039/d1sc00238d ◽

2021 ◽

Author(s):

Lewis Thomas-Hargreaves ◽

Marcus Giansiracusa ◽

Matthew Gregson ◽

Emanuele Zanda ◽

Felix O'Donnell ◽

...

Keyword(s):

Alkali Metal ◽

Single Molecule ◽

Ligand Field ◽

Single Molecule Magnet ◽

Field Effects ◽

Equatorial Ligand ◽

Metal Alkyls

Treatment of the new methanediide-methanide complex [Dy(SCS)(SCSH)(THF)] (1Dy, SCS = {C(PPh2S)2}2-) with alkali metal alkyls and auxillary ethers produces the bis-methanediide complexes [Dy(SCS)2][Dy(SCS)2(K(DME)2)2] (2Dy), [Dy(SCS)2][Na(DME)3] (3Dy) and [Dy(SCS)2][K(2,2,2-cryptand)] (4Dy). For...

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Lerf–Klinowski-type models of graphene oxide and reduced graphene oxide are robust in analyzing non-covalent functionalization with porphyrins

Scientific Reports ◽

10.1038/s41598-021-86880-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alexandra Siklitskaya ◽

Ewelina Gacka ◽

Daria Larowska ◽

Marta Mazurkiewicz-Pawlicka ◽

Artur Malolepszy ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Excited States ◽

Reduced Graphene ◽

Simulation Protocol ◽

Potential Applications ◽

H 26 ◽

High Level ◽

Experimental And Theoretical Studies ◽

Low Solubility

AbstractGraphene-based nanohybrids are good candidates for various applications. However, graphene exhibits some unwanted features such as low solubility in an aqueous solution or tendency to aggregate, limiting its potential applications. On the contrary, its derivatives, such as graphene oxide (GO) and reduced graphene oxide (RGO), have excellent properties and can be easily produced in large quantities. GO/RGO nanohybrids with porphyrins were shown to possess great potential in the field of photocatalytic hydrogen production, pollutant photodegradation, optical sensing, or drug delivery. Despite the rapid progress in experimental research on the porphyrin-graphene hybrids some fundamental questions about the structures and the interaction between components in these systems still remain open. In this work, we combine detailed experimental and theoretical studies to investigate the nature of the interaction between the GO/RGO and two metal-free porphyrins 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) and 5,10,15,20-tetrakis(4-hydroxyphenyl) porphyrin (TPPH)]. The two porphyrins form stable nanohybrids with GO/RGO support, although both porphyrins exhibited a slightly higher affinity to RGO. We validated finite, Lerf–Klinowski-type (Lerf et al. in J Phys Chem B 102:4477, 1998) structural models of GO ($$\hbox {C}_{59}\hbox {O}_{26}\hbox {H}_{26}$$ C 59 O 26 H 26 ) and RGO ($$\hbox {C}_{59}\hbox {O}_{17}\hbox {H}_{26}$$ C 59 O 17 H 26 ) and successfully used them in ab initio absorption spectra simulations to track back the origin of experimentally observed spectral features. We also investigated the nature of low-lying excited states with high-level wavefunction-based methods and shown that states’ density becomes denser upon nanohybrid formation. The studied nanohybrids are non-emissive, and our study suggests that this is due to excited states that gain significant charge-transfer character. The presented efficient simulation protocol may ease the properties screening of new GO/RGO-nanohybrids.

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