cis-Bis(l-DOPA- κ 2N,O)copper(II) monohydrate: synthesis, crystal structure, and approaches to the analysis of pseudosymmetry

The crystal structure of the cis isomer of cis-bis(l-DOPA- κ 2N,O)copper(II) monohydrate (l-DOPA is 3,4-dihydroxy-l-phenylalanine) (CuLD), [Cu(C9H10NO4)2] · H2O, is a singular example of a structurally characterized, homoleptic, crystalline metal l-DOPA complex. CuLD crystallizes in the space group P21, with Z ′ = 2. The two independent molecules are square planar, and are interconnected by a linear hydrogen-bonded chain containing 12 independent hydrogen bonds. The copper ions in both molecules have weak apical intermolecular Cu...O interactions [2.739   (2) and 2.973   (2)   Å ] with catechol – OH groups. A survey of the Cambridge Structural Database suggested that cis and trans isomers of Cu(NH2 – C – CO2)2 amino acid complexes are equally likely to occur. 12 strong O — H...O and N — H...O hydrogen bonds stabilize an unusual linear arrangement of the Cu complexes. The Cu...Cu ′ distances along the chain are nearly equal [5.0739   (3) and 5.1107   (3)   Å ] and the Cu...Cu ′ ...Cu angles are nearly linear [176.75   (1) ° ]. The MATCH procedure available in the Oxford University Crystals for Windows package was used to carry out a detailed analysis of the relationship between the two independent molecules. MATCH has some particular advantages in studying the details of pseudosymmetry, which include: (i) no atomic-order requirements; (ii) the pseudosymmetry matrix is readily available, which allows quick insight into the symmetry elements in...
Source: Acta Crystallographica Section C - Category: Chemistry Authors: Tags: Parkinson's disease homolepic complex pseudosymmetry linear packing crystal structure research papers Source Type: research