Zwitterionic and neutral binuclear complexes formed from copper(II) hexafluoroacetylacetonate and an amino alcohol

Reaction of anhydrous Cu(hfac) 2 (hfacH = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione) with 2-(diisopropylamino)ethanol yields two different binuclear copper(II) complexes. Compound 1, [Cu(hfac)2(μ-OCH2CH2NH(i-Pr)2)]2, Cu2C36H42O10N2F24, consists of centrosymmetric dimers containing two cis-Cu(hfac)2 moieties that are bridged by two zwitterionic 2-(diisopropylammonio)ethoxide ions. Cell parameters are a = 11.6516(13); b = 14.0117(17); c = 15.3258(17) Å; β = 105.75(9)° in space group P21/n. The copper ions exhibit tetragonally distorted octahedral coordination, with two of the Cu -O(hfac) distances showing characteristic elongation (2.2858(16) and 2.3192(17) Å). Compound 2, [Cu(hfac)((i-Pr)2NCH2CH2O)]2, Cu2C26H38O6N2F12, also contains centrosymmetric dimers; these are formed by two squarepyramidal moieties joined at their bases. Cell parameters are a = 7.7353(5); b = 13.6166(17); c = 15.683(2) Å; β = 98.23(1)° in space group P21/n. In this structure the apical Cu - O(hfac) distance is elongated (2.254(4) Å), and the O atoms of the 2-(diisopropylamino)ethoxide ions are bridging

Endo and Exo coordination to cofacial binuclear copper(II) complexes

A structural study of internal (endo) and external (exo) coordination to cofacial binuclear complexes is reported. Cu2(NBA)2(NBAH 2=3,3′-[2,7-naphthalenediylbis(methylene)]-bis(2,4- pentanedione)) is large enough to accommodate 2-methylpyrazine as an intramolecularly coordinated guest molecule. Cu2(NBA)2(μ-(2-Mepyz))·4CH2Cl 2, Cu2C53H58N2O8Cl 8, orthorhombic, space group Pnma (No. 62); a = 22.4674(11); b = 22.230(2); c = 11.4520(6) Å; V = 5719.6(6) Å3 (at 100 K); Z = 4; R = 0.058; Rw = 0.167 for 344 parameters and 5339 reflections with I \u3e 2σ(I). The Cu2(NBA)2(μ-(2-Mepyz)) molecules possess crystallographic m symmetry, with the Cu⋯Cu vector (Cu⋯Cu′ 7.4801(8) Å) perpendicular to the mirror plane; this requires disorder in the 2-Mepyz guests. The two Cu(acac)2 moieties (acacH = 2,4-pentanedione) are not quite parallel (dihedral angle between (acac)2 planes = 3.93(7)°), forming a slightly wider opening on the side of the methyl group in the 2-Mepyz guest. On the other hand, the cavity in Cu2(XBA)2 (XBAH2 = 3,3′-[1.3-phenylenebis(methylene)]-bis(2,4-pentanedione)) is smaller, so that CH3CN must bind externally. Cu2(XBA)2(CH3CN)2·1.5CH 3CN·H2O, Cu2C43H52.5N3.5O9, monoclinic, space group P21/c (No. 14); a = 11.7361(16); b = 14.197(3); c = 13.299(3) Å; β= 92.22(2)°; V = 2214.3(7) Å3 (at 100 K); Z = 2; R = 0.044; Rw = 0.124 for 275 parameters and 4983 reflections with I \u3e 2σ(I). This structure contains centrosymmetric Cu2(XBA)2 units (Cu⋯Cu′ 4.8302(12) Å) with externally coordinated CH3CN ligands. The crystal packing in Cu2(NBA)2(μ-(2-Mepyz))·4CH2Cl 2, which contains close π contacts between layers of Cu2(NBA)2(μ-(2-Mepyz)) moieties, is also similar to that in three other crystalline host-guest adducts M2(NBA)2(μ-G). Cu2(XBA)2(CH3CN)2·1.5CH 3-CN·H2O does not contain similar layers of molecules, presumably because the adduct molecules do not have the same type of exposed flat surfaces

GR 24 enantiomers: Synthesis, NMR spectroscopy, X-ray crystallography, and separation by chiral electrokinetic capillary chromatography

Chiral discrimination of enantiomers of 2-methyl-4-(2-oxo-2,3,3a,8b-tetrahydro-4H-indeno[1,2b]furan-3-yl-idenemethoxy )but-2-en-4-olide (commonly referred to as GR 24) by three polymeric chiral surfactants (PCS) is studied by use of chiral polymeric surfactant capillary electrophoresis (CPSCE). The CPSCE results indicate that the optical configurations of valine residues on the PCS backbone affect chiral resolution and elution order of GR24 stereoisomers. The L- and D-forms of poly(sodium N-undecanoyl valinate) provide baseline separation of all four enantiomers while the DL-form separates diastereomers of GR 24 (1). A model is presented rationalizing the migration behavior and chiral resolution of 1 in CPSCE. The actual configuration of the stereogenic centers of GR 24 and 3-[(2,5-dihydro-3-methyl-2-oxo-5-furanyl)oxo]-methylene-3,3a,6,6a-tetrahydro- 2H-cyclopenta[b]furan-2-one (GR 7) is established by a concerted application of high-resolution nuclear magnetic resonance spectroscopy and X-ray crystallography

Structures of anhydrous and hydrated copper(II) hexafluoroacetylacetonate

Crystal structure analyses are reported for anhydrous copper(II) hexafluoroacetylacetonate (Cu(hfac)2) and for two of its hydrates. The anhydrous compound (Cu(hfac)2, 1: P1; at 100 K, a = 5.428(1), b = 5.849(1), c = 11.516(3) Å; α = 81.47(2), β = 74.57(2), γ = 86.96(2)°; Z = 1) contains centrosymmetric square-planar complexes with close intermolecular Cu···F contacts. The geometry of the complex is similar to that previously reported for Cu(hfac)2· toluene. The monoaquo compound (Cu(hfac)2(H2O), 2: P21/c; at 100 K, a = 10.8300(8), b = 6.5400(6), c = 21.551(3) Å; β = 90.282(8)°; Z = 4) consists of square-pyramidal molecules with apical H2O ligands, and close-lying F atoms in the sixth coordination sites. The major difference between this structure and the two other polymorphs previously reported is the nature and direction of hydrogen bonds. The yellow-green solid formed from Cu(hfac)2 with excess H2O is identified as the trihydrate. In crystalline form it is the previously unreported [trans-Cu(hfac)2-(H2O)2] ·H2O (3: P1; at 150 K, a = 8.3899(3), b = 9.6011(3), c = 11.4852(4) Å; α = 72.397(2), β = 79.161(2), γ = 87.843(2)°; Z = 2). There is no conclusive evidence in favor of any solid with the composition Cu(hfac)2· 2H2O