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

Noh, Elnoor Abbakar Abdelrahman; Zhang, Jingping

doi:10.1016/j.chemphys.2006.07.042

Cited by 21 publications

(17 citation statements)

References 56 publications

(88 reference statements)

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“…4) for each calculated result using different functional and basis set. The negative DE values indicate that complex 2 is antiferromagnetic, which is in good agreement with the experiment [30] and our previous theoretical results [23]. The DE value of complex 2 significantly depends on the functional used and slightly on the basis set.…”

Section: Influence Of the Basis Setssupporting

confidence: 84%

“…3 (a plot of DE versus different mixed basis set only) we can extract the following consideration: the complex 1 has positive DE, by each functional and basis set, which indicates that this complex has a ferromagnetic character in agreement with the experiments data [30] and our previous theoretical results [23].…”

Section: Influence Of the Basis Setssupporting

confidence: 55%

“…Much of the success in the application of DFT methods in transition metal complexes has its origin in the development of the so called hybrid functionals, in which some amount of exact exchange is included in the exchange functional [31]. Our previous reports [23,24] demonstrated that the DFT method is able to handle larger systems under the DFT framework and the BS approach, and provides very good results for evaluation of the J for the target system with a good degree of accuracy. Therefore, the DFT combined with the BS approach was adopted in our calculations on the magnetic interaction between the transition metal ion and the radical aminoxyl ligands.…”

Section: Dft Calculationmentioning

confidence: 99%

“…The BS approach is a useful tool that is accessible through the DFT framework and successfully applied in studying and rationalizing magnetic behavior of some transition metal complexes as shown by different authors [6,[12][13][14][15][16][17][18][19][20][21]. This method has been used to elucidate effective exchange integrals between local spins in organic radicals and transition metal complexes, but clearly the results can only be as accurate as the electronic structure method used with [7,[22][23][24].…”

Section: Introductionmentioning

confidence: 99%

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Broken symmetry approach and density functional theory investigation on hetero-spin system consisting of copper(II) and aminoxyl radicals: Comparison and reliability of different basis sets approaches

Noh

Zhang

2009

Journal of Molecular Structure: THEOCHEM

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Section: Influence Of the Basis Setssupporting

confidence: 84%

Section: Influence Of the Basis Setssupporting

confidence: 55%

Section: Dft Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Broken symmetry approach and density functional theory investigation on hetero-spin system consisting of copper(II) and aminoxyl radicals: Comparison and reliability of different basis sets approaches

Noh

Zhang

2009

Journal of Molecular Structure: THEOCHEM

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“…23 A large literature has developed on this and related broken-symmetry approaches. [24][25][26][27][28][29][30][31][32][33] Broken-symmetry solutions have also been studied in other contexts, and it has often been found that it is important to allow the orbitals to break symmetry in order to get a qualitatively correct description of the system. [33][34][35][36][37][38][39][40][41][42] The energies of the broken-symmetry states are often used without correcting for their spin character.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory in Transition-Metal Chemistry: Relative Energies of Low-Lying States of Iron Compounds and the Effect of Spatial Symmetry Breaking

Sorkin

Iron

Truhlar

2008

J. Chem. Theory Comput.

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Abstract:The ground and lower excited states of Fe 2 , Fe 2 -, and FeO + were studied using a number of density functional theory (DFT) methods. Specific attention was paid to the relative state energies, the internuclear distances (r e ), and the harmonic vibrational frequencies (ω e ). A number of factors influencing the calculated values of these properties were examined. These include basis sets, the nature of the density functional chosen, the percentage of HartreeFock exchange in the density functional, and constraints on orbital symmetry. A number of different types of generalized gradient approximation (GGA) density functionals (straight GGA, hybrid GGA, meta-GGA, and hybrid meta-GGA) were examined, and it was found that the best results were obtained with hybrid GGA or hybrid meta-GGA functionals that contain nonzero fractions of HF exchange; specifically, the best overall results were obtained with B3LYP, M05, and M06, closely followed by B1LYP. One significant observation was the effect of enforcing symmetry on the orbitals. When a degenerate orbital (π or δ) is partially occupied in the 4 Φ excited state of FeO + , reducing the enforced symmetry (from C 6v to C 4v to C 2v ) results in a lower energy since these degenerate orbitals are split in the lower symmetries. The results obtained were compared to higher level ab initio results from the literature and to recent PBE+U plane wave results by Kulik et al. (Phys. Rev. Lett. 2006, 97, 103001). It was found that some of the improvements that were afforded by the semiempirical +U correction can also be accomplished by improving the form of the DFT functional and, in one case, by not enforcing high symmetry on the orbitals.

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Synthesis, Structure and Magnetic Properties of Some Copper(II) Complexes Supported by Pendant Calix[4]arene Ligands

Jäschke,

Kischel,

Börner

et al. 2023

Eur J Inorg Chem

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The synthesis and characterization of three new calix[4]arene ligands bearing two pendant acylhydrazone arms and some of their Cu2+ complexes, namely [Cu(L1‐2H)(MeOH)] (3), [Cu(L1ꞌ‐H)(Cl)(2‐hydroxy‐1‐naphthaldehyde)] (4), [Cu2(L2‐2H)2] (5) and [Cu4(L3‐2H)2(OH)2(ClO4)2] (6) are described. The ligands are obtained by simple imine condensation reactions between calix[4]arene‐1,3‐bis‐acyl‐hydrazides and the corresponding carbaldehydes. The Cu2+ ions are always situated in 5‐membered chelate rings, either in a deprotonated −O−CR=N−N=CHR (enolate) or a neutral O=CR−NH−N=CHR (keto) form. In 3 and 4 a 5‐membered chelate ring is formed through interaction of the Cu2+ ion with the naphtholato group. Additional MeOH, chlorido or naphthaldehyde ligands complete the planar (3) or square pyramidal (4) coordination spheres. The thiophenes in 5 do not interact with the Cu2+ ions and dimerization of [CuL] entities occurs to produce centrosymmetric 2:2 complexes with four‐coordinated Cu2+ ions. In 6, two dinuclear [Cu2(L3‐2H)(OH)] subunits are connected by μ1,3‐bridging ClO4− ions. The magnetic properties of polycrystalline samples of 5 and 6 were studied by variable temperature magnetic susceptibility measurements. The χ′′(T) vs T plots indicate antiferromagnetic exchange interactions. The exchange interactions in 6 (J = −4.8 cm‐1) were found to be stronger than in 5 (J = −0.54 cm‐1). This is also supported by broken symmetry DFT calculations.

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

Cited by 21 publications

References 56 publications

Broken symmetry approach and density functional theory investigation on hetero-spin system consisting of copper(II) and aminoxyl radicals: Comparison and reliability of different basis sets approaches

Broken symmetry approach and density functional theory investigation on hetero-spin system consisting of copper(II) and aminoxyl radicals: Comparison and reliability of different basis sets approaches

Density Functional Theory in Transition-Metal Chemistry: Relative Energies of Low-Lying States of Iron Compounds and the Effect of Spatial Symmetry Breaking

Synthesis, Structure and Magnetic Properties of Some Copper(II) Complexes Supported by Pendant Calix[4]arene Ligands

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