Dinuclear copper(II) complexes with the new [Cu2(μ-OR)(μ-OAc)2]+ (R = alkyl) core: preparation and characterization of [Cu2(OR)(OAC)2(bpy)2]+ (R = Me, Et, Prn) salts

摘要: Abstract Procedures are described for the synthesis of complexes containing cations [Cu2(μ-OR)(μ-O2CMe)2(bpy)2]+ (R = Me, Et, Prn). Treatment Cu2(O2CMe)4(H2O)2 with 2 equivs bpy and 1 equiv. NaOH in anhydrous EtOH, followed by addition NBu4nPF6 MeCN gave highly crystalline blue [Cu2(OEt)(O2CMe)2(bpy)2]PF6) (1a) ≈70% yield. The corresponding reaction dry MeOHMeCN led to green crystals methoxo analogue [Cu2(OMe)(O2CMe)2(bpy)2](PF6) (2a), also Layering a methanolic solution 1a mixture Et2O hexanes clean, high-yield conversion complex 2a. Complexes 1a, 2a [Cu2(OPrn)(O2CMe)2(bpy)2] (PF6) (3) were prepared from reactions compound [Cu2(OH)(O2CMe)2(bpy)2](PF6)·3DMF an excess appropriate alcohol. In order study influence counterion on structure [Cu2(OR)(O2CMe)2(bpy)2]+ ions, blue-turquoise [Cu2(OEt)(O2CMe)2(bpy)2](ClO4) (1b) methoxo-bridged compund [Cu2(OMe)(O2CMe)2(bpy)2](ClO4) (2b) obtained same manner as 2a, respectively. both determined X-ray diffraction consisted triply-bridged pairs copper(II) atoms. Two bridging ligands syn,syn η1:η1:μ2 acetate groups, third being OR− ion; terminal molecule completes five-coordination at each metal atom. Cut3Cu separations 3.093(1) 3.230(1) A coordination geometry is best square pyramidal; oxygen atoms [O(30) O(32)] one occupy basal positions while oxygens other [O(34) O(36)] apical two pyramids. cation consists distorted trigonal bipyramids sharing common apex. solid-state electronic IR spectra discussed terms nature bonding structures cyclic voltammetry reveals quasi-reversible reduction ≈−0.75 V vs ferrocene, irreversible Ep −1.83 −1.63 yielding copper metal, which deposits electrode.