Assessment of Density Functional Theory for Describing the Correlation Effects on the Ground and Excited State Potential Energy Surfaces of a Retinal Chromophore Model

FeIFeI Fe2(S2C3H6)(CO)6(µ-CO) (1a–CO) and its FeIFeII cationic species (2a+–CO) are the simplest model of the CO-inhibited [FeFe] hydrogenase active site, which is known to undergo CO photolysis within a temperature-dependent process whose products and mechanism are still a matter of debate. Using density functional theory (DFT) and time-dependent density functional theory (TDDFT) computations, the ground state and low-lying excited-state potential energy surfaces (PESs) of 1a–CO and 2a+–CO have been explored aimed at elucidating the dynamics of the CO photolysis yielding Fe2(S2C3H6)(CO)6 (1a) and [Fe2(S2C3H6)(CO)6]+ (2a+), two simple models of the catalytic site of the enzyme. Two main results came out from these investigations. First, a–CO and 2a+–CO are both bound with respect to any CO dissociation with the lowest free energy barriers around 10 kcal mol−1, suggesting that at least 2a+–CO may be synthesized. Second, focusing on the cationic form, we found at least two clear excited-state channels along the PESs of 2a+–CO that are unbound with respect to equatorial CO dissociation.

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On the applicability of time-dependent density functional theory (TDDFT) and semiempirical methods to the computation of excited-state potential energy surfaces of perylene-based dye-aggregates

International Journal of Quantum Chemistry ◽

10.1002/qua.25337 ◽

2016 ◽

Vol 117 (6) ◽

pp. e25337 ◽

Cited By ~ 18

Author(s):

Christof Walter ◽

Veronika Krämer ◽

Bernd Engels

Keyword(s):

Density Functional Theory ◽

Excited State ◽

Potential Energy Surfaces ◽

Density Functional ◽

Time Dependent ◽

Semiempirical Methods ◽

Functional Theory ◽

State Potential ◽

Energy Surfaces ◽

Dependent Density

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The Photochemistry of Fe2(S2C3H6)(CO)6(µ-CO) and its Oxidized Form, Two Simple [FeFe]-Hydrogenase CO-Inhibited Models. A DFT and TDDFT Investigation

10.20944/preprints202101.0488.v1 ◽

2021 ◽

Author(s):

Federica Arrigoni ◽

Giuseppe Zampella ◽

Luca De Gioia ◽

Claudio Greco ◽

Luca Bertini

Keyword(s):

Density Functional Theory ◽

Excited State ◽

Potential Energy Surfaces ◽

Density Functional ◽

Temperature Dependent ◽

Cationic Form ◽

Functional Theory ◽

Co Dissociation ◽

State Potential ◽

Energy Surfaces

FeIFeI Fe2(S2C3H6)(CO)6(µ-CO) (1a-CO) and its FeIFeII cationic species (2a+-CO) are the simplest model of the CO-inhibited [FeFe] hydrogenase active site, which is known to undergo CO photolysis within a temperature- dependent process whose products and mechanism are still a matter of debate. Using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) computations, the ground state and low-lying excited state potential energy surfaces (PESs) of 1a-CO and 2a+-CO have been explored aimed at elucidating the dynamics of the CO photolysis yielding Fe2(S2C3H6)(CO)6 (1a) and Fe2(S2C3H6)(CO)6+ (2a+), two simple models of the catalytic site of the enzyme. Two main results came out from these investigations. First, a-CO and 2a+-CO are both bound with respect to any CO dissociation with lowest free energy barriers around 10 kcal mol-1, suggesting that at least 2a+-CO might be synthetized. Second, focusing on the cationic form, we found at least two clear excited state channels along the PESs of 2a+-CO that are unbound with respect to equatorial CO dissociation.

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Theoretical Investigation of the Decarbonylation of Acetaldehyde by Ni+2 Using Density Functional Theory

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.446-447.168 ◽

2013 ◽

Vol 446-447 ◽

pp. 168-171

Author(s):

Hong Fei Liu ◽

Xin Min Min ◽

Hai Xia Yang

Keyword(s):

Density Functional Theory ◽

Potential Energy ◽

Potential Energy Surfaces ◽

Density Functional ◽

Transition Metal Ions ◽

Basis Sets ◽

Functional Theory ◽

Representative System ◽

Energy Surfaces ◽

Ground Potential

The decarbonylation of acetaldehyde assisted by Ni+2, which was selected as a representative system of transition metal ions assisted decarbonylation of acetaldehyde, has been investigated using density functional theory (B3LYP) in conjunction with the 6-31+G** basis sets in C,H,O atoms and Lanl2dz basis sets in Ni atom The geometries and energies of the reactants, intermediates, products and transition states relevant to the reaction were located on the triplet ground potential energy surfaces of [Ni, O, C2,H4]+2. Our calculations indicate the decarbonylation of acetaldehyde takes place through four steps, that is, encounter complexation, CC activation, aldehyde H-shift and nonreactive dissociation, it is that CC activation by Ni+2that lead to the decarbonylation of acetaldehyde.

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