Synthesis, characterization and crystal structure of 6-Chloro-4,4′-dimethyl-2,2′-bipyridine and 4,4′-Dimethyl 2,2′-bipyridine N-Oxide

• Crystal structures of bipyridines ligands.
• Weak interaction analysis by Hirshfeld surface calculations and fingerprint decomposition.
• CH
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• O bonds and the minimization of empty spaces are the prevailing interactions

The synthesis, the NMR characterization and the crystal structure of 6-Chloro 4,4′-dimethyl 2,2′-bipyridine and of the reaction intermediate 4,4′-Dimethyl 2,2′-bipyridine N-Oxide are here reported. The target compound crystallizes in the orthorhombic system while the intermediate is monoclinic. In both structures, the molecules are linked by weak interactions. The structure of the reaction intermediate N-oxide is characterized by a dihedral angle between the two phenyl rings of 161.77° while the other is almost planar with a dihedral angle of 179.15°. The crystal packing was investigated, also with the aid of Hirshfeld surface analysis. In the N-oxide reaction intermediate the packing is governed by CH–O interactions, while in the product the packing is simply driven by minimizing the voids and thus maximizing the density, with a prevalence of H
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• H and C
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• H contacts, as indicated by fingerprint decomposition analysis.