Synthesis, Structures, and DFT Study of CuBr Based Coordination Polymers via in Situ Reduction of Copper(II)

This paper describes the one-pot synthesis of two CuBr based coordination polymers, {[Cu­(μ<sub>2</sub>-L<sup>1</sup>)­Br]·1.87H<sub>2</sub>O}<sub><i>n</i></sub> (<b>1</b>) and {[Cu­(μ<sub>2</sub>-L<sup>2</sup>)­Br]·C<sub>4</sub>H<sub>10</sub>O}<sub><i>n</i></sub> (<b>2</b>), where L<sup>1</sup> = 2,3-dihydro-5,6-bis­(4-methoxyphenyl)­pyrazine and L<sup>2</sup>= 5,6-diphenyl-2,3-dihydropyrazine, upon reduction of copper­(II) at ambient conditions. The structures have been confirmed by single crystal X-ray diffraction analysis. Both complexes are found to be highly inert toward oxidation. Finally, a density functional theory (DFT) study of the energetic features of several noncovalent interactions observed in the solid state has been analyzed and characterized using Bader’s theory of “atoms in molecules” and the cuprophilic interactions in complex <b>2</b> using natural bond orbital methodology.