Symmetry-adapted cluster f-orbitals and a vector method for generally oriented f-orbital overlaps

Chiu, Ying‐Nan; Wang, Frederick E.

doi:10.1007/bf00526770

Cited by 5 publications

(1 citation statement)

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“…A conventional (spin-orbit coupling omitted) study on the model for 3 yields a triplet ground state with two electrons in quasi degenerate, singly occupied f orbitals; consistent with the group theoretic analysis. 58 The calculated f orbitals are mixtures of the 5f general set; 107 the occupied orbitals that would have π overlap with the acetylide ligand most closely resemble f xz 2 and f yz 2 (Figure 7). The lowest M S = 0 "singlet" state is one wherein the two singly occupied orbitals are "singlet coupled" via a broken symmetry solution.…”

Section: Resultsmentioning

confidence: 96%

Experimental Evidence for Magnetic Exchange in Di- and Trinuclear Uranium(IV) Ethynylbenzene Complexes

2010

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We report the preparation and magnetic property investigations of a structurally related family of mono-, di-, and trinuclear U(IV) aryl acetylide complexes. The reaction between [(NN'(3))UCl] and lithiated aryl acetylides leads to the formation of the hexacoordinate complexes [(NN'(3))U(CCPh)(2)(Li.THF)] (1) and [(NN'(3))(2)U(2)(p-DEB)(THF)] (2) as red-brown and yellow-green crystalline solids, respectively. In contrast, combining the uranacycle [(bit-NN'(3))U] (bit-NN'(3) = [N(CH(2)CH(2)NSi(t)BuMe(2))(2)(CH(2)CH(2)Si(t)BuMeCH(2)]) with stoichiometric amounts of mono-, bis-, and tris(ethynyl) benzenes affords the yellow-green pentacoordinate arylacetylide complexes [(NN'(3))U(CCPh)] (3), [(NN'(3))(2)U(2)(m-DEB)] (4), [(NN'(3))(2)U(2)(p-DEB)] (5), and [(NN'(3))(3)U(3)(TEB)] (6), where NN'(3) = [N(CH(2)CH(2)NSi(t)BuMe(2))(3)]. The measured magnetic susceptibilities for 1-6 trend toward non-magnetic ground states at low temperatures. Nevertheless, the di- and trinuclear pentacoordinate compounds 4-6 appear to display weak magnetic communication between the uranium centers. This communication is modeled by fitting of the direct current (DC) magnetic susceptibility data, using the spin Hamiltonian H = -2J(S(i) x S(j)). These results are consistent with weak ferromagnetic coupling for complexes 4-6 (J = 4.76, 2.75, and 1.11 cm(-1), respectively), while the fit for 2 is consistent with a near-negligible exchange interaction (J = -0.05 cm(-1)). Geometry-optimized Stuttgart/6-31 g* B3LYP hybrid DFT calculations were carried out (spin-orbit coupling omitted) on model complexes of 3-5. The mononuclear complex shows a triplet ground state with singly occupied degenerate f orbitals. The meta- and para-bridged species are computed to show very weak ferro- and antiferromagnetic coupling, respectively. All three complexes show only small net spin density on the acetylide-containing ligands. The monomeric phenylacetylide complex 3 undergoes a reversible redox couple at -1.02 V versus [Cp(2)Fe](+/0), assignable to an oxidation of U(IV) to U(V).

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Section: Resultsmentioning

confidence: 96%

Experimental Evidence for Magnetic Exchange in Di- and Trinuclear Uranium(IV) Ethynylbenzene Complexes

2010

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A tensor representation of the real spherical functions for the continuous group O in cartesian coordinates: Example of eulerian rotations

Boudeville

Rousseau-Violet

1990

Int J of Quantum Chemistry

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The aim of this article is to give a practical way for the use of real spherical functions in another frame than the frame in which they have been defined. For instance, we calculate physical properties from a local frame and use them in the general frame, deduced one from the other by Eulerian rotations on the coordinates. The power of the method is in the use of Cartesian coordinates and in the definition of a scalar product between these functions to set up the complete vectorial space generated by these representations of the group 0;. I. AimsIn the early days of quantum chemistry state of art were ab initio CI calculations on 1s and 2s 2p functions for a few atoms. In the field of catalysis, as well as in solid state calculations for magnetism or spin-dependent properties, one is forced to consider the 3d "chemistry" of Fe, Co, Ni, Cu, and in the VIII metal group, Ni, Pd, and Pt by also considering relativistic effects. The nd multiplets give rise to many difficult problems that can be solved by, say, Wigner-Racah algebra and Clebsch-Gordan coupling coefficients [l-41, and the mf configurations for rare earths are even more complex [5-61. For binuclear properties one can use a kind of Slater-Koster parameter [6-91 but when we need only a one function property to study them from a local point of view these methods are inadequate. Rare earth calculations are now of great interest not only in the uranide [5] group but also for material science components in new high-technology innovative materials: catalysis, superconductivity, magnets and maglevs, postcombustion catalysts, optical glasses, solar cells, optic fibers, electric bulbs, ceramic oxygen sensors, and, color centers in cathodic displays [lo]. All these applications need a convenient description of nd-nf real functions in order to understand the specificity of these atomic properties.

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Symmetry analysis of the electronic structure of polyhedron clusters M12(Ih), M12(Oh) and M60(Ih)

Wang

Chiu

1991

Journal of Molecular Structure: THEOCHEM

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Symmetry-adapted cluster f-orbitals and a vector method for generally oriented f-orbital overlaps

Cited by 5 publications

References 14 publications

Experimental Evidence for Magnetic Exchange in Di- and Trinuclear Uranium(IV) Ethynylbenzene Complexes

Experimental Evidence for Magnetic Exchange in Di- and Trinuclear Uranium(IV) Ethynylbenzene Complexes

A tensor representation of the real spherical functions for the continuous group O in cartesian coordinates: Example of eulerian rotations

Symmetry analysis of the electronic structure of polyhedron clusters M12(Ih), M12(Oh) and M60(Ih)

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