Synthesis, spectroscopic, and biological studies on copper(II) complexes containing equatorial–apical chloride bridges: crystal structure of [Cu<sub>2</sub>(μ-Cl)<sub>2</sub>(O-2-butoxyethylpyridine-2-carboximidate)<sub>2</sub>Cl<sub>2</sub>]

<div><p>Three new [Cu<sub>2</sub>(μ-Cl)<sub>2</sub>(O-2-alkoxyethylpyridine-2-carboximidate)<sub>2</sub>Cl<sub>2</sub>] complexes, where alkoxy = methoxy, ethoxy, and butoxy, were synthesized and characterized by elemental analyses, FTIR spectra, electronic spectra, EPR, conductance, magnetic moment, powdered X-ray powder diffraction, and X-ray single-crystal diffraction. The three complexes contain chloride as a bridging ligand and in each complex the planar bidentate ligand binds the metal ion via the pyridine-N and the NH of the imino ether group. The X-ray crystal structure of [Cu<sub>2</sub>(μ-Cl)<sub>2</sub>(O-2-butoxyethylpyridine-2-carboximidate)<sub>2</sub>Cl<sub>2</sub>] shows that it crystallizes as a centrosymmetric dinuclear species in which each copper(II) is in a distorted square pyramid. Magnetic field-induced partial molecular alignment has been observed in polycrystalline samples of <b>2</b> and <b>3</b> when cooled in a magnetic field of 1 T at 77 K. The interaction of these complexes with Calf thymus DNA has been explored and the values of binding constant, <i>K</i><sub>b</sub> for <b>1</b>, <b>2</b>, and <b>3</b> are 1.524 × 10<sup>3</sup>, 5.587 × 10<sup>3</sup>, and 6.362 × 10<sup>3</sup> (ML<sup>−1</sup>)<sup>−1</sup>, respectively. Complexes were screened for antimicrobial activities by the agar well diffusion technique.</p></div>