Dimethyl 2,2′-bipyridine-6,6′-dicarboxyl­ate and bis­(dimethyl 2,2′-bipyridine-6,6′-dicarboxyl­ato-κ²N,N′)copper(I) tetra­fluoro­borate

The single-crystal X-ray structures of dimethyl 2,2′-bipyridine-6,6′-dicarboxylate, C₁₄H₁₂N₂O₄, and the copper(I) coordination complex bis­(dimethyl 2,2′-bipyridine-6,6′-dicarboxylato-κ²N,N′)copper(I) tetra­fluoro­borate, [Cu(C₁₄H₁₂N₂O₄)₂]BF₄, are reported. The uncoordinated ligand crystallizes across an inversion centre and adopts the anti­cipated anti pyridyl arrangement with coplanar pyridyl rings. In contrast, upon coordination of copper(I), the ligand adopts an arrangement of pyridyl donors facilitating chelating metal coordination and an increased inter-pyridyl twisting within each ligand. The distortion of each ligand contrasts with comparable copper(I) complexes of unfunctionalized 2,2′-bipyridine.

(1,3-Dimethyl­imidazolidine-2-selone-[kappa]Se)bis­(1,10-phenanthroline-[kappa]²N,N')copper(II) bis­(perchlorate) and bis­(2,2'-bipyridyl-[kappa]²N,N')(imidazolidine-2-thione-[kappa]S)copper(II) bis­(perchlorate)

In the first title salt, [Cu(C₁₂H₈N₂)₂(C₅H₁₀N₂Se)](ClO₄)₂, the Cu^II centre occupies a distorted trigonal-bipyramidal environment defined by four N donors from two 1,10-phenanthroline (phen) ligands and by the Se donor of a 1,3-dimethyl­imidazolidine-2-selone ligand, with the equatorial plane defined by the Se and by two N donors from different phen ligands and the axial sites occupied by the two remaining N donors, one from each phen ligand. The Cu-N distances span the range 1.980 (10)-2.114 (11) Å and the Cu-Se distance is 2.491 (3) Å. Inter­molecular [pi]-[pi] contacts between imidazolidine rings and the central rings of phen ligands generate chains of cations. In the second salt, [Cu(C₁₀H₈N₂)₂(C₃H₆N₂S)](ClO₄)₂, the Cu^II centre occupies a similar dis­torted trigonal-bipyramidal environment comprising four N donors from two 2,2'-bipyridyl (bipy) ligands and an S donor from an imidazolidine-2-thione ligand. The equatorial plane is defined by the S donor and two N donors from different bipy ligands. The Cu-N distances span the range 1.984 (6)-2.069 (7) Å and the Cu-S distance is 2.366 (3) Å. Inter­molecular [pi]-[pi] contacts between imidazolidine and pyridyl rings form chains of cations. A major difference between the two structures is due to the presence in the second complex of two N-H...O hydrogen bonds linking the imidazolidine N-H hydrogen-bond donors to perchlorate O-atom acceptors.