A designed and potentially decadentate ligand for use in lanthanide(III) catalysed biomass transformations: targeting diastereoselective trans-4,5-diaminocyclopentenone derivatives

The goal of this study was to design a ligand system which can accommodate single lanthanide(III)-ions and investigate the properties of the resulting complexes. The complexes of all the accesible lanthanides and yttrium with the new ligand LH6 = N,N′-dimethyl-N,N′-ethylene-bis(5-bromo-3-(1H-benzimidazol-2-yl)hydrazineylidene)-2-hydroxybenzylamine) were obtained in high yield at room temperature under aerobic reaction conditions. The corresponding compounds were characterised using X-ray diffraction, FT-IR, elemental analysis and the optical properties of all complexes were investigated using UV-vis and fluorescence spectroscopy. The air stable complexes efficiently transform biomass furfural to trans-4,5-cyclopentenones in high yield

A multifunctional use of bis(methylene)bis(5-bromo-2-hydroxyl salicyloylhydrazone): From metal sensing to ambient catalysis of A3 coupling reactions

The potential use of bis(methylene)bis(5-bromo-2-hydroxylsalicyloylhydrazone) as a multifunctional fluorescence sensor for Cu(2+), Ni(2+), Co(2+) and Fe(2+) ions was investigated. The optical behaviour shows an increase in an absorption band at 408 nm which can be ascribed to the d–d transition (UV-vis) of the metal ions and a concomitant decrease in fluorescence intensity at 507 nm. The crystallographic analysis shows the binding site of the sensor to two Cu(2+) ions and confirms the stoichiometry of 1 : 2 (ligand to metal) which is in good agreement with a Job plot analysis. Furthermore the Cu(2+)-complex catalyses A3 coupling reactions at 1 mol% catalytic loading; chiral propargylamine derivatives were obtained in high yield after 24 h reaction time under ambient conditions

Tetranuclear Cu(II)-chiral complexes: synthesis, characterization and biological activity

Tetranuclear chiral Cu(ii)-Schiff-base complexes S-1 and R-1, were synthesised using enantiomerically pure (S)-(H(2)vanPheol) and (R)-(H(2)vanPheol) ligands respectively in the ratio of 1 : 1 of Cu(NO(3))(2) to (S/R)-(H(2)vanPheol) in MeOH at room temperature. A pair of polynuclear chiral Cu(ii)-cluster complexes were characterized using single-crystal X-ray diffraction, elemental analysis, infrared and CD spectroscopy. The results revealed the importance of these chiral ligands encouraging the arrangement of copper metal in non-centrosymmetric polar packing. The potential of the novel [Cu(4)(S/R-vanPheol)(2)(S/R-HvanPheol)(2)(CH(3)OH)(2)](NO(3))(2) complexes as biologically active compounds was assessed in particular regarding their anti-proliferative and anti-microbial properties

Synthesis of <i>gem</i>-Difluoromethylenated Bicyclo[<i>m.n.</i>0]alkan-1-ols and Their Ring-Expansion to <i>gem</i>-Difluoromethylenated Macrocyclic Lactones

Fluoride-catalyzed stereoselective nucleophilic addition of PhSCF₂SiMe₃ (<b>1</b>) to α-carboethoxycycloalkanones <b>2</b> followed by intramolecular radical cyclization of the resulting <i>cis</i>-<b>3</b> adduct afforded the corresponding <i>gem</i>-difluoromethylenated bicyclic compounds <b>4</b>, which underwent ring-expansion followed by the Baeyer–Villiger-type oxidation of the resulting macrocyclic ketone intermediates to give <i>gem</i>-difluoromethylenated macrocyclic lactones <b>5</b>