Magnetic exchange interactions in cyano-bridged MoIII binuclear complexes: Broken-symmetry and density functional theory calculations

2005 ◽  
Vol 102 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Yi-Quan Zhang ◽  
Cheng-Lin Luo ◽  
Zhi Yu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Exchange Interactions ◽  
Density Functional Theory Calculations ◽  
Broken Symmetry ◽  
Binuclear Complexes ◽  
Magnetic Exchange ◽  
Functional Theory

scholarly journals Substituent effects in the decarboxylation reactions of coordinated arylcarboxylates in dinuclear copper complexes, [(napy)Cu2(O2CC6H4X)]+

2017 ◽  
Vol 23 (6) ◽  
pp. 351-358 ◽  
Author(s):  
Qiuyan Jin ◽  
Jiaye Li ◽  
Alireza Ariafard ◽  
Allan J Canty ◽  
Richard AJ O’Hair
Keyword(s):  
Density Functional Theory ◽  
Transition State ◽  
Density Functional ◽  
Copper Complexes ◽  
Substituent Effects ◽  
Density Functional Theory Calculations ◽  
Molecular Formula ◽  
Binuclear Complexes ◽  
Aryl Group ◽  
Functional Theory

A combination of gas-phase ion trap mass spectrometry experiments and density functional theory (DFT) calculations have been used to examine the role of substituents on the decarboxylation of 25 different coordinated aromatic carboxylates in binuclear complexes, [(napy)Cu2(O2CC6H4X)]+, where napy is the ligand 1,8-naphthyridine (molecular formula, C8H6N2) and X = H and the ortho ( o), meta ( m) and para ( p) isomers of F, Br, CN, NO2, CF3, OAc, Me and MeO. Two competing unimolecular reaction pathways were found: decarboxylation to give the organometallic cation [(napy)Cu2(C6H4X)]+ or loss of the neutral copper benzoate to yield [(napy)Cu]+. The substituents on the aryl group influence the branching ratios of these product channels, but decarboxylation is always the dominant pathway. Density functional theory calculations reveal that decarboxylation proceeds via two transition states. The first enables a change in the coordination mode of the coordinated benzoate in [(napy)Cu2(O2CC6H4X)]+ from the thermodynamically favoured O, O-bridged form to the O-bound form, which is the reactive conformation for the second transition state which involves extrusion of CO2 with concomitant formation of the CO2 coordinated organometallic cation, [(napy)Cu2(C6H4X)(CO2)]+, which then loses CO2 in the final step to yield [(napy)Cu2(C6H4X)]+. In all cases the barrier is highest for the second transition state. The o-substituted benzoates show a lower activation energy than the m-substituted ones, while the p-substituted ones have the highest energy, which is consistent with the experimentally determined normalised collision energy required to induce fragmentation of [(napy)Cu2(O2CC6H4X)]+.

Subsystem density-functional theory for interacting open-shell systems: spin densities and magnetic exchange couplings

2020 ◽  
Vol 224 ◽  
pp. 201-226
Author(s):  
Anja Massolle ◽  
Johannes Neugebauer
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Open Shell ◽  
Broken Symmetry ◽  
Easy Access ◽  
Magnetic Exchange ◽  
Functional Theory ◽  
Spin Densities

Subsystem DFT allows easy access to spin densities for arbitrary broken-symmetry states of radical aggregates.

Application of periodic density functional theory calculations for exploring copper(II) coordination effects on the mesophase behavior of p-n-alkoxybenzoic acids

2019 ◽  
Vol 18 (01) ◽  
pp. 1950006 ◽  
Author(s):  
Li-Fen Wang ◽  
Cheng-Xian You
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Valuable Insight ◽  
Binuclear Complexes ◽  
Functional Theory ◽  
Bidentate Coordination ◽  
Smectic C ◽  
Cu Complexes ◽  
Insight Into

Copper(II) benzoates ([Formula: see text]OBA-Cu) with various terminal alkoxy carbon numbers, [Formula: see text]–12, were prepared from [Formula: see text]-[Formula: see text]-alkoxy benzoic acids (nOBAs). Fourier transform infrared (IR) experiments suggested that dimerization through copper(II) chelating bidentate coordination created [Formula: see text]OBA-Cu with a linear rod-like structure, similar to the hydrogen-bonded structure of its parent [Formula: see text]OBA. However, the coordination structure of [Formula: see text]OBA-Cu changed during heating. Periodic density functional theory calculations provided valuable insight into the possible arrangement of the parent and copper(II)-coordinated [Formula: see text]OBAs. The formation of binuclear complexes between two adjacent [Formula: see text]OBA-Cu dimers forced [Formula: see text]OBA-Cu to arrange itself in a layer and exhibit smectic A mesophase. Accordingly, four types of IR stretching absorption of benzoyl carbonyl were observed in binuclear [Formula: see text]OBA-Cu complexes, replacing the original symmetric and asymmetric vibrations of benzoyl carboxylate in chelating bidentate coordination. The lateral association by [Formula: see text]–[Formula: see text] interactions between adjacent parent [Formula: see text]OBA dimers preferred a progressive smectic C arrangement. The origin of the odd–even effect was understood from the consideration of the molecular structure.

MAGNETIC EXCHANGE IN POLYNUCLEAR TRANSITION METAL SYSTEM: AB INITIO CASPT2 AND DENSITY FUNCTIONAL THEORY STUDY ON TRIANGULAR COPPER(II) COMPLEXES

2006 ◽  
Vol 05 (spec01) ◽  
pp. 501-514 ◽  
Author(s):  
HAIYAN WEI ◽  
ZHIDA CHEN
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Magnetic Coupling ◽  
Exchange Interactions ◽  
Coupling Constants ◽  
Magnetic Exchange ◽  
Functional Theory ◽  
Symmetry Approach ◽  
Spin Electronic

The magnetic exchange interactions for five representative triangular Copper(II) complexes: antiferromagnetic Cu 3( TiPB )6 (1), [ Cu 3(μ3- OH )( aaat )3( H 2 O )3]2+ (2), [ PPN ]2 [ Cu 3(μ3- O )(μ- pz )3 Cl 3] (3), [ PPN ][ Cu 3(μ3- OH )(μ- pz )3 Cl 3] (4) and ferromagnetic [ Cu 3(2- CH 3 C 6 H 4 CO 2)4{( C 2 H 5)2 NC 2 H 4 O }2 H 2 O ] (5) are investigated by using density functional theory combined with broken-symmetry approach (DFT-BS) and ab initio CASPT2 method. Our calculated results show that DFT-BS has remarkable dependence on the particular chosen XC functionals and is system-dependent, while the calculations at CASPT2 level of theory are able to give the accurate magnetic coupling constants. Qualitatively, the two theoretical methods reproduce consistently the linear correlation between the magnetic coupling constants and the departure of the (μ3- O ) oxygen atom from the { Cu3 } plane in the complexes (3) and (4). Spin population analyses reveal that the DFT-BS method overestimates the spin electronic delocalization from the Cu(II) center to the bridging ligands.

Spin decontamination of broken-symmetry density functional theory calculations: deeper insight and new formulations

2015 ◽  
Vol 17 (22) ◽  
pp. 14375-14382 ◽  
Author(s):  
Nicolas Ferré ◽  
Nathalie Guihéry ◽  
Jean-Paul Malrieu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Broken Symmetry ◽  
Functional Theory ◽  
Physically Based

This work proposes rigorous and physically based spin decontamination factors for broken-symmetry treatments of diradicals.

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