Molecular Magnetic Materials Based on {Co (Tp*)(CN) } Cyanidometallate: Combined Magnetic, Structural and Co NMR Study.

The cyanidocobaltate of formula fac-PPh [Co ( Tp)(CN) ] ⋅ CH CN (1) has been used as a metalloligand to prepare polynuclear magnetic complexes ( Tp=hydrotris(3,5-dimethylpyrazol-1-yl)borate). The association of 1 with in situ prepared [Fe (bik) (MeCN) ](OTf) (bik=bis(1-methylimidazol-2-yl)ketone) leads to a molecular square of formula {[Co {( Tp)}(CN) ] [Fe (bik) ] }(OTf)  ⋅ 4MeCN ⋅ 2H O (2), whereas the self-assembly of 1 with preformed cluster [Co (OH )(piv) (Hpiv) ] in MeCN leads to the two-dimensional network of formula {[Co (piv) ] [Co ( Tp)(CN) ]  ⋅ 2CH CN} (3). These compounds were structurally characterized via single crystal X-ray analysis and their spectroscopic (FTIR, UV-Vis and Co NMR) properties and magnetic behaviours were also investigated.

Correction: Thermo- and electro-switchable Cs⊂{Fe-Fe} cubic cage: spin-transition and electrochromism.

Correction for 'Thermo- and electro-switchable Cs⊂{Fe4-Fe4} cubic cage: spin-transition and electrochromism' by Jana Glatz et al., Chem. Commun.

Thermo- and electro-switchable Cs⊂{Fe-Fe} cubic cage: spin-transition and electrochromism.

A mixed valence Cs⊂{Fe4-Fe4} cyanido-cube was synthesized and structurally characterized. The molecule, which is robust in solution, shows remarkable electronic versatility. Electrochromic properties associated with nine different electronic states are observed in solution together with a thermo-induced spin-transition in the solid state.

Probing the Local Magnetic Structure of the [Fe (Tp)(CN) ] Building Block Via Solid-State NMR Spectroscopy, Polarized Neutron Diffraction, and First-Principle Calculations.

The local magnetic structure in the [Fe (Tp)(CN) ] building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutron diffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanido ligands: Spin-polarization on the carbon atoms and spin-delocalization on the nitrogen atoms. The results of our combined density functional theory (DFT) and multireference calculations were found in good agreement with the PND results and the experimental NMR chemical shifts.

Thermally-Induced Spin Crossover and LIESST Effect in the Neutral [Fe(bik)(NCX)] Complexes: Variable-Temperature Structural, Magnetic, and Optical Studies (X = S, Se; bik = bis(1-methylimidazol-2-yl)ketone).

Two new iron(II) neutral complexes of bis(1-methylimidazol-2-yl)ketone (bik) with molecular formula [Fe(bik)(NCS)] () and [Fe(bik)(NCSe)] () have been synthesized and characterized by magnetic measurements, single-crystal X-ray diffraction, and solid state UV-vis spectroscopy. The temperature dependent magnetic susceptibility measurements of crystalline samples of both compound show the occurrence of a gradual spin transition centered at = 260 K and 326 K, respectively. The crystal structures of both compounds were determined at different temperatures, below and above the transition, in order to detect the structural changes associated with the spin transition.