Ultrafast dynamics of ligand-field excited states

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.

Download Full-text

A ligand field theory-based methodology for the characterization of the Eu 2+ [Xe]4f 6 5d 1 excited states in solid state compounds

Chemical Physics Letters ◽

10.1016/j.cplett.2015.01.031 ◽

2015 ◽

Vol 622 ◽

pp. 120-123 ◽

Cited By ~ 9

Author(s):

Amador García-Fuente ◽

Fanica Cimpoesu ◽

Harry Ramanantoanina ◽

Benjamin Herden ◽

Claude Daul ◽

...

Keyword(s):

Field Theory ◽

Solid State ◽

Excited States ◽

Ligand Field ◽

Ligand Field Theory ◽

The Eu

Download Full-text

Metal centered ligand field excited states: Their roles in the design and performance of transition metal based photochemical molecular devices

Coordination Chemistry Reviews ◽

10.1016/j.ccr.2010.11.016 ◽

2011 ◽

Vol 255 (5-6) ◽

pp. 591-616 ◽

Cited By ~ 180

Author(s):

Paul S. Wagenknecht ◽

Peter C. Ford

Keyword(s):

Transition Metal ◽

Excited States ◽

Molecular Devices ◽

Ligand Field ◽

And Performance

Download Full-text

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

10.26434/chemrxiv.6998048.v1 ◽

2018 ◽

Author(s):

Justin K. Kirkland ◽

Shahriar N. Khan ◽

Bryan Casale ◽

Evangelos Miliordos ◽

Konstantinos Vogiatzis

Keyword(s):

Excited States ◽

Function Theory ◽

Weak Field ◽

Ligand Field ◽

Model Complexes ◽

Coordination Environment ◽

Reactivity Descriptors ◽

Field Effects ◽

Catalytically Active ◽

High Level

<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>

Download Full-text

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

10.26434/chemrxiv.6998048 ◽

2018 ◽

Author(s):

Justin K. Kirkland ◽

Shahriar N. Khan ◽

Bryan Casale ◽

Evangelos Miliordos ◽

Konstantinos Vogiatzis

Keyword(s):

Excited States ◽

Function Theory ◽

Weak Field ◽

Ligand Field ◽

Model Complexes ◽

Coordination Environment ◽

Reactivity Descriptors ◽

Field Effects ◽

Catalytically Active ◽

High Level

<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>

Download Full-text