Synthesis of copper(II) halide dimers with 2-amino-5-methylpyridine and serendipitous copper catalyzed synthesis of 3-bromo-2-ethyl-5-methyl-1H-pyrrolo[2,3-b]pyridine
Reaction of CuX2·nH2O (X = Cl, n = 2; X = Br, n = 0) with 2-amino-5-methylpyridine (5MAP) in acetonitrile yielded [(5MAP)2CuX2]2 (1, Cl; 2, Br). The compounds are isomorphous and crystallize in the monoclinic space group P21 /n as bihalide bridged dimers. Variable temperature magnetic measurements show very weak exchange in the two compounds (-2.1(1) K) which may correlate with previously proposed magnetostructural correlations for bihalide bridged Cu(II) dimers. In attempts to prepare 2 in 2-butanone as solvent, [(3-Br-2-Et-5-Mepyrpy)(CH3CO2)4Cu2] (3) was serendipitously isolated (3-Br-2-Et-5-Mepyrpy = 3-bromo-2-ethyl-5-methyl-7H-pyrrolido[2,3-b]pyridinium). The bicyclic ligand was synthesized in situ by condensation of 5MAP with the solvent; the acetate ions were generated by copper(II) catalyzed Baeyer-Villiger oxidation of the solvent. A mechanism for the synthesis is proposed. The resulting Cu-paddlewheel compound exhibits strong (-400 K) antiferromagnetic interactions. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
Journal of Coordination Chemistry
Chittim, Carina L.; Faber, Kesli; Dickie, Diane A.; Landee, Christopher; Telfer, Shane G.; and Turnbull, Mark M., "Synthesis of copper(II) halide dimers with 2-amino-5-methylpyridine and serendipitous copper catalyzed synthesis of 3-bromo-2-ethyl-5-methyl-1H-pyrrolo[2,3-b]pyridine" (2023). Chemistry. 14.