Synthesis of 3d metallic single-molecule magnets

The [enPd(II)]2+ (en = ethylenediamine) unit has emerged as a versatile building block in molecular self-assembly. In particular, the 90° coordination angle of the metal has been judiciously used in the design of new discrete two- and three-dimensional structures. Our last 15 years of work with the Pd(II)-cornered unit is summarized in this Account, from the spontaneous formation of a Pd4 square metal complex to a family of architectures such as cages, bowls, boxes, tubes, catenanes, and spheres.

Coordination assemblies from a Pd(II)-cornered square complex.

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Single-chain magnets: Theoretical approach and experimental systems

Strategies towards single-chain magnets

Using the anionic precursor [(Tp)Fe(CN)3]-, a new one-dimensional Ising cyanide-bridged chain, [(Tp)2FeIII2(CN)6Cu(CH3OH).2CH3OH]n, has been prepared. The crystal structure and magnetic studies demonstrate that it is a single-chain magnet and the blocking temperature is ca. 6 K.

The observation of superparamagnetic behavior in molecular nanowires

[(Tp)8(H2O)6CuII6FeIII8(CN)24]4+: A Cyanide‐Bridged Face‐Centered‐Cubic Cluster with Single‐Molecule‐Magnet Behavior

Tricyanometalate molecular chemistry: A type of versatile building blocks for the construction of cyano-bridged molecular architectures

Dicyanometalate chemistry: A type of versatile building block for the construction of cyanide-bridged molecular architectures

The six-coordinated mononuclear manganese(III) complex [Mn(5-Br-sal-N-1,5,8,12)]ClO4 has been synthesized and isolated in crystalline form. Magnetic measurements and variable-temperature single-crystal X-ray crystallography corroborated with theoretical analysis provided firm evidence for the spin-crossover effects of this system. The monomeric complex cations are made by a hexadentate mixed-donor Schiff base ligand imposing a distorted octahedral geometry and subtle structural effects determining the manifestation of the variable spin properties of the manganese(III) centers. The spin crossover in [Mn(5-Br-sal-N-1,5,8,12)]ClO4 has resulted in an unprecedented crystallographic observation of the coexistence of high-spin (HS; S = 2) and low-spin (LS; S = 1) manganese(III) complex cations in equal proportions around 100 K. At room temperature, the two crystallographically distinct manganese centers are both HS. Only one of the two slightly different units undergoes spin crossover in the temperature range ∼2...

Shi Wang

Papers

The observation of superparamagnetic behavior in molecular nanowires

[(Tp)8(H2O)6CuII6FeIII8(CN)24]4+: A Cyanide‐Bridged Face‐Centered‐Cubic Cluster with Single‐Molecule‐Magnet Behavior

Tricyanometalate molecular chemistry: A type of versatile building blocks for the construction of cyano-bridged molecular architectures

Dicyanometalate chemistry: A type of versatile building block for the construction of cyanide-bridged molecular architectures

Case study on a rare effect: the experimental and theoretical analysis of a manganese(III) spin-crossover system.