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Université de Fribourg

Electrostatic control on endo/exo selectivity in ionic cycloaddition

Tamilmani, Venkatachalam ; Daul, Claude A. ; Venuvanalingam, P.

In: Chemical Physics Letters, 2005, vol. 416(4-6), p. 354

DFT method has been used in combination with various basis sets to model the ionic cycloaddition of cationic heteroaromatic diene, 2,3-dimethylisoquinoliniuim ion with cyclopentadiene with a view to understand the factors that influence the stereochemical outcome of the reaction. Calculations show that this reaction is an inverse electron demand type reaction and it passes through highly...

Université de Fribourg

Asymmetric μ2-1,1-azido bridged copper(II) complex: Synthesis, X-ray structure, magnetic study and DFT calculations

Zbiri, Mohamed ; Saha, Sandip ; Adhikary, Chandan ; Chaudhuri, Siddhartha ; Daul, Claude A. ; Koner, Subratanath

In: Inorganica Chimica Acta, 2006, vol. 359, p. 1193

A new rare variety asymmetric μ2-1,1-azido bridged copper(II) complex has been synthesized and characterized structurally and magnetically. The complex [Cu2L2(μ2-1,1-N3)2] · H2O · CH3OH (L = 1-(N-ortho-hydroxyacetophenimine)-2-aminoethane) (1), crystallizes in monoclinic space group, P21/n, with a = 9.469(4) Angstrom capital A, ring, b = 12.526(8) Angstrom capital A, ring, c = 12.899(10)...

Université de Fribourg

Theoretical studies on the electronic properties and the chemical bonding of transition metal complexes using dft and ligand field theory

Atanasov, Mihail ; Daul, Claude A.

In: Chimia, 2005, vol. 59, no. 7-8, p. 504-510

The research activity within our laboratory of computational chemistry at the University of Fribourg is presented. In this review, a brief outline of a recently proposed Ligand Field Density Functional Theory (LFDFT) model for single nuclear and its extension to dimer transition metal complexes is given. Applications of the model to dinuclear complexes are illustrated for the interpretation...

Université de Fribourg

Modeling properties of molecules with open d-shells using density functional theory

Atanasov, Mihail ; Daul, Claude A.

In: Comptes Rendus Chimie, 2005, vol. 8(9-10), p. 1421-1433

An overview of the theory and applications of a recently proposed ligand-field density functional theory (LFDFT) is given. We describe a procedure based on DFT allowing to deduce the parameters of this non-empirical LF approach consisting of the following steps: (i) an average of configuration (AOC) DFT calculation, with equal occupancies of the d-orbitals is carried out (ii) with...

Université de Fribourg

Chemical bonding in molecules and complexes containing d-elements based on DFT

Atanasov, Mihail ; Daul, Claude A. ; Penka Fowe, Emmanuel

In: Monatshefte für Chemie / Chemical Monthly, 2005, vol. 136, no. 6, p. 925-963

Metal–ligand bonding in transition metal halide molecules and complexes with different central ions, oxidations states, and coordination numbers: CrIII X₆³⁻, CrIVX₄, CrIIX₂ (X = F,Cl,Br,I), MIIICl₆³⁻(M = Mo,W), MIII (H₂O)₆³⁺(M = Cr,Co) and Re₂Cl₈²⁻ has...

Université de Fribourg

Investigating the M*He exciplexes, M = {Li,Na,K,Rb,Cs,Fr}: Density functional approach

Zbiri, Mohamed ; Daul, Claude A.

In: Journal of Chemical Physics, 2004, vol. 121(23), p. 11625-11628

Potential curves for the ground and the first lowest excited states of the MHe (where M = {Li,Na,K,Rb,Cs,Fr}) exciplexes are calculated using the density functional theory (DFT) formalism. Relativistic calculations are carried out with and without spin-orbit (SO) coupling effect, using a zeroth order regular approximation (ZORA) approach. The depth De and position...

Université de Fribourg

Ground States, Excited States and Metal-Ligand Bonding in Rare Earth Hexachloro Complexes: A DFT Based Ligand Field Study

Atanasov, Mihail ; Daul, Claude A. ; Güdel, Hans-Ulrich ; Wesolowski, Tomasz A. ; Zbiri, Mohamed

In: Inorganic Chemistry, 2005, vol. 44(8), p. 2954-2963

Metal (4f)-ligand (Cl 3p) bonding in LnCl63- (Ln = Ce to Yb) complexes has been studied on the basis of 4f->4f and Cl,3p->4f charge-transfer spectra and on the analysis of these spectra within the valence bond configuration interaction model to show that mixing of Cl 3p into the Ln 4f ligand field orbitals does not exceed 1%. Contrary to this, Kohn-Sham formalism...

Université de Fribourg

Improved coupled perturbed Hartree–Fock and Kohn–Sham convergence acceleration

Weber, Valéry ; Daul, Claude A.

In: Chemical Physics Letters, 2003, vol. 370(1-2), p. 99-105

A derivative version of the well-known direct inversion in the iterative subspace (DIIS) algorithm is presented. The method is used to solve the coupled perturbed Hartree–Fock (CPHF) equation to obtain the first and second derivatives of the density matrix with respect to an external electric field which, in this case, leads to the electric molecular polarizability and hyperpolarizability. Some...

Université de Fribourg

Investigation of NLO properties of substituted (M)-tetrathia-[7]-helicenes by semiempirical and DFT methods

Daul, Claude A. ; Ciofini, Ilaria ; Weber, Valéry

In: International Journal of Quantum Chemistry, 2003, vol. 91, no. 3, p. 297-302

In this article, we propose a theoretical study of static and dynamic polarizability α, first hyperpolarizability β, and second hyperpolarizability γ of substituted (M)-tetrathia-[7]-helicenes. Both a semiempirical approach, in the case of static and dynamic properties, and density functional theory, in the case of static electric properties, were used. The nonlinear optical (NLO) properties...