Syntheses and crystal structures of a new pyrazine dicarboxamide ligand, N 2,N 3-bis-(quinolin-8-yl)pyrazine-2,3-dicarboxamide, and of a copper perchlorate binuclear complex.

ABSTRACT: The title pyrazine dicarboxamide ligand, N 2,N 3-bis-(quinolin-8-yl)pyrazine-2,3-dicarboxamide (H2L1), C24H16N6O2, has a twisted conformation with the outer quinoline groups being inclined to the central pyrazine ring by 9.00?(6) and 78.67?(5)°, and by 79.94?(4)° to each other. In the crystal, molecules are linked by C-H?O hydrogen bonds, forming layers parallel to the (10) plane, which are in turn linked by offset ?-? inter-actions [inter-centroid distances 3.4779?(9) and 3.6526?(8)?Å], forming a supra-molecular three-dimensional structure. Reaction of the ligand H2L1 with Cu(ClO4)2 in aceto-nitrile leads to the formation of the binuclear complex, [?-(3-{hy-droxy[(quinolin-8-yl)imino]-meth-yl}pyrazin-2-yl)[(quinolin-8-yl)imino]-methano-lato]bis-[diaceto-nitrile-copper(II)] tris-(per-chlor-ate) aceto-nitrile disolvate, [Cu2(C24H15N6O2)(CH3CN)4](ClO4)3·2CH3CN or [Cu2(HL1-)(CH3CN)4](ClO4)3·2CH3CN (I). In the cation of complex I, the ligand coordinates to the copper(II) atoms in a bis-tridentate fashion. A resonance-assisted O-H?O hydrogen bond is present in the ligand; the position of this H atom was located in a difference-Fourier map. Both copper(II) atoms are fivefold coordinate, being ligated by three N atoms of the ligand and by the N atoms of two aceto-nitrile mol-ecules. The first copper atom has a perfect square-pyramidal geometry while the second copper atom has a distorted shape. In the crystal, the cation and perchlorate anions are linked by a number of C-H?O hydrogen bonds, forming a supra-molecular three-dimensional structure.

SUBMITTER: Cati DS 

PROVIDER: S-EPMC7057382 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature