Induced Orbital Paramagnetism and Paratropism in Closed-Shell Molecules

Pelloni, Stefano; Lazzeretti, Paolo; Zanasi, Riccardo

doi:10.1021/jp903859k

Cited by 23 publications

(26 citation statements)

References 79 publications

(179 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reported (van Hecke & Horrocks, 1966) Calculated (dppe-2 P)NiCl 2 463 488 (459) (dppe-2 P)NiBr 2 481 506 (493) (dppe-2 P)NiI 2 521 536 (529) (dppp-2 P)NiCl 2 470 490 (dppp-2 P)NiBr 2 490 515 (dppp-2 P)NiI 2 559 a 550 magnetizability comparable to those of the molecules for which TIP is well established (such as BH and isoelectronic molecules) , 1993Pelloni et al, 2009;Ruud et al, 1995;Sauer et al, 1993;Stevens & Lipscomb, 1965). The magnitude of the individual contributions is similar and the corresponding excitations can be understood in terms of simple orbital considerations.…”

Section: Complexmentioning

confidence: 99%

Structure, magnetism and colour in simple bis(phosphine)nickel(II) dihalide complexes: an experimental and theoretical investigation

et al. 2013

View full text Add to dashboard Cite

The complex [1,2-bis(di-tert-butylphosphanyl)ethane-2 P,P 0 ]-diiodidonickel(II), [NiI 2 (C 18 H 40 P 2 ] or (dtbpe-2 P)NiI 2 , [dtbpe is 1,2-bis(di-tert-butylphosphanyl)ethane], is bright bluegreen in the solid state and in solution, but, contrary to the structure predicted for a blue or green nickel(II) bis(phosphine) complex, it is found to be close to square planar in the solid state. The solution structure is deduced to be similar, because the optical spectra measured in solution and in the solid state contain similar absorptions. In solution at room temperature, no 31 P{ 1 H} NMR resonance is observed, but the very small solid-state magnetic moment at temperatures down to 4 K indicates that the weak paramagnetism of this nickel(II) complex can be ascribed to temperature independent paramagnetism, and that the complex has no unpaired electrons. The red [1,2-bis(di-tert-butylphosphanyl)ethane-2 P,P 0 ]dichloridonickel(II), [NiCl 2 (C 18 H 40 P 2 ] or (dtbpe-2 P)NiCl 2 , is very close to square planar and very weakly paramagnetic in the solid state and in solution, while the maroon [1,2-bis(ditert-butylphosphanyl)ethane-2 P,P 0 ]dibromidonickel(II), [NiBr 2 (C 18 H 40 P 2 ] or (dtbpe-2 P)NiBr 2 , is isostructural with the diiodide in the solid state, and displays paramagnetism intermediate between that of the dichloride and the diiodide in the solid state and in solution. Density functional calculations demonstrate that distortion from an ideal square plane for these complexes occurs on a flat potential energy surface. The calculations reproduce the observed structures and colours, and explain the trends observed for these and similar complexes. Although theoretical investigation identified magnetic-dipole-allowed excitations that are characteristic for temperature-independent paramagnetism (TIP), theory predicts the molecules to be diamagnetic.

show abstract

Section: Complexmentioning

confidence: 99%

Structure, magnetism and colour in simple bis(phosphine)nickel(II) dihalide complexes: an experimental and theoretical investigation

et al. 2013

View full text Add to dashboard Cite

show abstract

“…We also noted that Sinha and Ghosh had reported the similar approach on this journal before [61]. Recently, Pelloni et al reviewed the Rebane's article and compared the method with CTOCD-PZ [55]. They wrote that the both methods are problematic to compute the one-electron wavefunctions with nodes.…”

Section: Pgmentioning

confidence: 80%

“…In the above procedure, we must solve the KK equation. Next, we will explain the difference between the KK method and some of the various gauge methods reported by Lazzeretti and coworkers [52][53][54][55]. First, in our method, ∇φ and A = 1 2 B× r in Eq.…”

Section: The Concept Of the Gauge Function Optimizationmentioning

confidence: 99%

Gauge function optimization 2: An accurately solvable model

Kubo

2011

Int J of Quantum Chemistry

View full text Add to dashboard Cite

ABSTRACT:The gauge function is optimized by using the Kennedy-Kobe (KK) theory [Kennedy and Kobe, Phys Rev A, (1984) 30, 51] for the anisotropic harmonic oscillator model in a magnetic field. We extend the KK model to describe various electron density distributions, which resemble to those for the ground and excited states of a H + 2 ion. The almost divergence-free current densities can be obtained by this method. The convergence is the fastest for the h2 model without the node of the wavefunction. When the wavefunction has nodal points, the first-and the second-order derivatives of the gauge function diverge at the nodes. We examine these singularities of the gauge function near the nodes both numerically and analytically. We also investigate the computed divergence-free current density in detail. Many new stagnation vortices appear after the gauge function optimization. The positions of the vortices are compared with those of the electron density maxima. When the maxima are separated from each other, some correlations are found between them. We also investigate the nuclear cusp condition of current density by inspecting the solutions of the KK equation when the electron density has a cusp. We find that the local mean velocity becomes a C 0 continuous function at the nucleus.

show abstract

“…Extended numerical experience demonstrates that these spatial models are the best tool available to understand molecular magnetism. [12, 15, 25–31] Rationalization of magnetotropicity by unsafe criteria allowing for a single number were to some extent acceptable in the past, when these newer tools were not within reach. They would seem obsolete at the present time.…”

Section: Introductionmentioning

confidence: 99%

“…An account of the basic theory underlying the idea of SG of a current density vector field is reported as Supporting Information available. Detailed treatments, which can be found in the cited literature,[12, 15, 25–33] are not reported in this article.…”

Section: Introductionmentioning

confidence: 99%

The ring current model of the pentaprismane molecule

et al. 2011

Self Cite

View full text Add to dashboard Cite

Three-dimensional models of the quantum-mechanical current density J(B) , induced in the electron cloud of the C(10)H(10) pentaprismane molecule by a magnetic field B applied along the C(5) (a C(2)) symmetry axis, orthogonal to the pentagonal (a rectangular) face, and denoted by B(‖) (B(⊥)), have been constructed. Predictions of near Hartree-Fock quality are reported for the diagonal components of magnetic tensors, magnetizability (ξ), nuclear shielding of carbon (σ(C)) and hydrogen (σ(H)), and virtual shielding at the center of mass (σ(CM)). The complicated spatial features of the induced electronic current-density field have been rationalized and compactly described via stagnation graphs that elucidate the details of its topological structure. A representation of J(B) is obtained by three-dimensional perspective plots and by planar maps visualizing phase portraits of electron flow in a series of molecular domains. Both streamline J(B) /|J(B) | and modulus |J(B) | are analyzed. These graphic tools illustrate the competition between diatropic and paratropic regimes which determine the magnitude of various components of magnetizability and magnetic shielding of hydrogen and carbon nuclei. Shielding density maps show that the differential Biot-Savart law explains magnetic shielding at hydrogen and carbon nuclei, and virtual shielding at ring and cage centers. Similarities and/or contrasting ring current effects on magnetotropicity are discussed by a comparison with triprismane C(6)H(6) and cubane C(8)H(8) .

show abstract

Induced Orbital Paramagnetism and Paratropism in Closed-Shell Molecules

Cited by 23 publications

References 79 publications

Structure, magnetism and colour in simple bis(phosphine)nickel(II) dihalide complexes: an experimental and theoretical investigation

Structure, magnetism and colour in simple bis(phosphine)nickel(II) dihalide complexes: an experimental and theoretical investigation

Gauge function optimization 2: An accurately solvable model

The ring current model of the pentaprismane molecule

Contact Info

Product

Resources

About