engleski

Crystal Structures of Three Bis(L- aminoacidato)Copper(II) Complexes: Polymeric Networks Based on Hydrogen Bonds and Intermolecular Cu...O Bonds

Crystal and molecular structures of trans- [Cu(Gly)2](H2O), trans-Cu(Val)2 and trans-Cu(Trp)2 complexes were determined. Two procedures were employed to obtain single crystals: crystallization from saturated solutions in the presence of excess solid ligand, and conversion of a bis(β -diketonate)copper(II) complex into a bis(L-aminoacidato)copper(II) complex via a difference in solubility and kinetic stability in whiskey medium. Crystal structures of all compounds are dominated by N-H...O hydrogen bonds and intermolecular Cu...O bonds. The structure of trans-[Cu(Gly)2](H2O) may be described in terms of polymeric layers of complex molecules. The interlinking of molecules in each layer can be rationalized to tetramers stabilized by intra- and intermolecular N-H...O hydrogen bonds. In case of trans-Cu(Val)2, the structure contains polymeric chains made up of complex dimers. Finally, trans- Cu(Trp)2 displays intermolecular hydrogen bonding of N-H...π type despite alternative hydrogen bond accepting sites in the crystal, anticipated to get more readily involved in hydrogen bonding.

amino acids ; copper(II) complexes

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