The synthesis and structure of two novel metal-di-2-pyridyl ketone oxime dimers

Single crystals of bis-N)N′,N″-di-2-pyridylketone oxime-O-nitratosilver(I)) (I) and di-μ-chlorobis((N,N″-2-pyridyl-2′-pyridinium ketone oxime)aquchlorocopper(II)) (II) were isolated from aqueous solutions and have been structurally characterized. The crystals of I were found to contain neutral dimers of Ag(di-2-pyridylketone oxime)NO₃ where both Ag(I) cations have obtained a CN = 4 and the geometry around the metal centers can be described as distorted tetrahedra. The structure of II revealed that di-2-pyridylketone oxime (dpk-o) does not bridge the metal centers but coordinates separately to the Cu cations through one pyridine N and the N of the Schiff base function. The nitrogen of the second pyridine ring is protonated and is not involved in coordination. Both Cu cations obtain a CN = 6 if one includes CuCl bond lengths up to 3.053(3) Å in the coordination sphere of the Cu cation. The geometry around each Cu can then be described as a distorted octahedron.