In situ Fe XAFS of reversible lithium insertion in a flexible metal organic framework material

X-ray absorption fine structure (XAFS) analysis of the Fe K-edge during lithium insertion and extraction into the metal organic framework material MIL-53 (Fe^III(OH, F)bdc; bdc = benzene-1,4-dicarboxylate) reveals changes in local atomic environment about iron during the process. The average oxidation state of iron is reduced upon lithium insertion, as evidenced by the edge shift of the XANES spectra, and this is accompanied by a lengthening of Fe–O bonds, seen in the EXAFS. In contrast, the EXAFS analysis shows that the closest Fe–Fe distance remains approximately constant during the insertion and extraction of lithium, consistent with a distortion of the structure due to its flexible nature. The process is reversible upon lithium extraction, proving the redox-active flexibility of the framework.     

A new synthesis of alkane and polyfluoroalkanesulfonyl chlorides

This study describes a new and advantageous procedure for the synthesis of alkanesulfonyl chlorides ( 2 ) by the reaction of alkyl thiocyanates ( 1 ) with sulfuryl chloride in a mixture of acetic acid and water. The alkanesulfonyl chlorides were obtained in good yields. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:355–361, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20559     

Solid-State and Solution Self-assembly Properties of Mono- and Bis-acetylide RuII Complexes Bearing Hydrogen-Bonding Amide Functions

In this work, we report our latest results regarding the self-assembly properties of two Ru-acetylides complexes and their corresponding free organic ligands, in solution and in the solid state. The four compounds show mesogenic properties, which we have rationalized thanks to extensive DSC, SAXS, POM, FTIR and molecular dynamic investigations. We clearly establish that hydrogen bonds stabilize the supramolecular structures, and that introducing the metal center and its coordination sphere induces large change in the liquid crystal properties. In addition, for the monoacetylide compound Ru₂ , solution-state studies helped us rationalize its supramolecular abilities. In particular, we demonstrate that Ru₂ follows an isodesmic growth supramolecular polymerization in aromatic solvent.     

Si-Tethered Bis- and Tris-Malonates for the Regioselective Preparation of Fullerene Multi-Adducts

Bis- and tris-malonates constructed around a silicon atom have been prepared by reaction of malonate derivatives bearing an alcohol function with di-tert-butylsilyl bis(trifluoromethanesulfonate) and tert-butyl(trichloro)silane, respectively. These compounds have been used for the regioselective bis- and tris-functionalization of C₆₀ under Bingel conditions. By changing the nature of the linker between the central Si atom and the reactive malonate groups, the malonate precursors have been optimized to produce specific bis- and tris-adducts with excellent regioselectivity. A complete understanding of the electronic and stereochemical factors governing the regioselectivity has been obtained by combining computational studies with a complete analysis of the by-products formed during the reactions of the Si-tethered tris-malonates with C₆₀. Finally, desilylation reactions of the resulting fullerene bis- and tris-adducts have been carried out to generate the corresponding acyclic fullerene bis- and tris-adducts bearing alcohol functions.