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

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)]+.

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

Faraday Discussions ◽

10.1039/d0fd00063a ◽

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.

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

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633619500068 ◽

2019 ◽

Vol 18 (01) ◽

pp. 1950006 ◽

Cited By ~ 1

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.

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Additive Decomposition of the Physical Components of the Magnetic Coupling from Broken Symmetry Density Functional Theory Calculations

Journal of Chemical Theory and Computation ◽

10.1021/ct400305h ◽

2013 ◽

Vol 9 (8) ◽

pp. 3429-3436 ◽

Cited By ~ 20

Author(s):

Esther Coulaud ◽

Jean-Paul Malrieu ◽

Nathalie Guihéry ◽

Nicolas Ferré

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Magnetic Coupling ◽

Density Functional Theory Calculations ◽

Broken Symmetry ◽

Additive Decomposition ◽

Functional Theory ◽

Physical Components

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Broken symmetry approach and density functional theory calculations for heterospin system consisting of copper(II) and aminoxyl radicals

Chemical Physics ◽

10.1016/j.chemphys.2006.07.042 ◽

2006 ◽

Vol 330 (1-2) ◽

pp. 82-89 ◽

Cited By ~ 15

Author(s):

Elnoor A.A. Noh ◽

Jingping Zhang

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Broken Symmetry ◽

Functional Theory ◽

Symmetry Approach ◽

Aminoxyl Radicals ◽

Broken Symmetry Approach

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

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633606002428 ◽

2006 ◽

Vol 05 (spec01) ◽

pp. 501-514 ◽

Cited By ~ 3

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.

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