Rationalization of the behavior of M2(CH3CS2)4I (M = Ni, Pt) chains at room temperature from periodic density functional theory and ab initio cluster calculations.

The electrical conductivities and plausible charge-ordering states in the room temperature (r.t.) phase for MMX chains [Ni(2)(dta)(4)I](∞) and [Pt(2)(dta)(4)I](∞) (dta = CH(3)CS(2)(-)) have been analyzed with periodic density functional theory (DFT) and correlated ab initio calculations combined with the effective Hamiltonian theory.

Towards a low-spin configuration in extended metal atom chains. Theoretical study of trimetallic systems with 22 metal electrons.

Different electronic configurations of a series of trinuclear heterometallic chains with 22 metallic electrons, MM'M(dpa)(4)X(2) (M = Co, Rh; M' = Ni, Pd; X = Cl, NCS), have been modelled in search of new systems with novel electrical properties. For this purpose, we explore the possibility of obtaining low-spin (extensively closed-shell) states by introducing chemical changes to the reference compound CoPdCo(dpa)(4)Cl(2) (1), isoelectronic to the herein studied systems, but possessing magnetically coupled localized electrons. The discussion is based on the orbital energies obtained by the DFT methodology.

Isotropic non-Heisenberg behavior in M3(dpa)4Cl2 extended metal atom chains.

Isotropic deviations to the standard Heisenberg Hamiltonian have been extracted for a series of trinuclear extended metal atom chain complexes, namely, [Ni(3)(dpa)(4)Cl(2)], and the hypothetical [NiPdNi(dpa)(4)Cl(2)] and [Pd(3)(dpa)(4)Cl(2)], following a scheme recently proposed by Labéguerie and co-workers (J. Chem. Phys 2008, 129, 154110) within the density functional theory framework.

Analysis of the magnetic coupling in M3(dpa)4Cl2 systems (M = Ni, Pd, Cu, Ag) by ab initio calculations.

The magnetic exchange parameter (J) of a series of neutral and oxidized trinuclear extended metal atom chain complexes [M(3)(dpa)(4)Cl(2)](0/1+), where dpa is the anion of di(2-pyridyl)amine, has been extracted employing the complete active space second-order perturbation theory (CASPT2). The computed magnetic coupling constant for Ni(3)(dpa)(4)Cl(2) (-98 cm(-1)) and the mono-oxidized Cu(3) complex (-35 cm(-1)) are in excellent agreement with the experimental estimates. This consistence is though not achieved for Cu(3)(dpa)(4)Cl(2), with three S = 1/2 magnetic centers, for which we surprisingly obtain 1/3 of the experimental value only.