Exploring magnetic properties at the molecular level is a challenge that has been met by developing many experimental and theoretical solutions, such as polarized neutron diffraction (PND), muon-spin rotation (μ-SR), electron paramagnetic resonance (EPR), SQUID-based magnetometry measurements, and advanced modeling on open-shell systems and relativistic calculations. These methods are powerful tools that shed light on the local magnetic response in specifically designed magnetic materials such as contrast agents, for MRI, molecular magnets, magnetic tags for biological NMR, etc. All of these methods have their advantages and disadvantages.
View Article and Find Full Text PDFThe control of ligand-field splitting in iron (II) complexes is critical to slow down the metal-to-ligand charge transfer (MLCT)-excited states deactivation pathways. The gap between the metal-centered states is maximal when the coordination sphere of the complex approaches an ideal octahedral geometry. Two new iron(II) complexes ( and ) prepared from pyridylNHC and pyridylquinoline type ligands, respectively, have a near-perfect octahedral coordination of the metal.
View Article and Find Full Text PDFTo evaluate the contribution of triethylsilyl α,α-di-n-propylglycine, namely TESDpg, to induce a defined secondary structure, we have prepared model tripeptides in which TESDpg was inserted in three different positions. Studies in solid state and in solution with adapted techniques showed that TESDpg was able to induce a nascent 3 helix in both crystal and solution states.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
November 2016
The coordination polymer {[Cu(SiF)(CHN)]·2CHN·5HO} , systematic name: poly[[bis-(μ-4,4'-bi-pyridine)(μ-hexa-fluorido-silicato)copper(II)] 4,4'-bi-pyridine disolvate penta-hydrate], contains pores which are filled with water and 4,4'-bi-pyridine mol-ecules. As a result of the presence of these ordered species, the framework changes its symmetry from 4/ to 2/. The 4,4'-bi-pyridine guest mol-ecules form chains inside the 6.
View Article and Find Full Text PDFThe structure of the photoluminescent compound hexaaquadichloridoneodymium(III) chloride has been redetermined from single-crystal X-ray diffraction data at 100 K, with the aim of providing an accurate structural model for the bulk crystalline material. The crystal structure may be described as a network of [NdCl2(H2O)6](+) cations with distorted square-antiprism geometry around the Nd(III) centre. The Nd(III) cation and the nonbonded Cl(-) anion are both located on twofold symmetry axes.
View Article and Find Full Text PDFTMSCH(2)Li and TMSCH(2)Li-LiDMAE have been used efficiently for bromine-lithium exchange in 2-bromo-, 3-bromo-, and 2,5-dibromopyridines under noncryogenic conditions, while low temperatures (-78 to -100 degrees C) are always needed with n-BuLi. The aminoalkoxide LiDMAE induced a remarkable C-2 selectivity with 2,5-dibromopyridines in toluene at 0 degrees C, which was unprecedented at such a temperature. The lithiopyridines were successfully reacted with electrophiles also under noncryogenic conditions giving the expected adducts in good yields.
View Article and Find Full Text PDFThe first regioselective C-4 lithiation of (S)-nicotine has been realized using TMSCH2Li as basic reagent in toluene. The reaction proceeded under mild conditions with a small excess of electrophile. The 4-chloro derivative was subsequently metallated at C-5 with the same basic reagent in THF at -78 degrees C.
View Article and Find Full Text PDFA TMSCH2Li-based reagent promoted the first C-3 lithiation of DMAP opening a direct access to functional diversity in acylation catalysts.
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