First X-ray structure of a cis-isomer of cobalt(III) aromatic carboxylate: Synthesis, and characterization of [cis-Co(en)2(C8H7O2)2](C8H7O2) · 2H2O, where C8H7O2 = p-methylbenzoate

A new cobalt(III) complex salt, [cis-Co(en)2(C8H7O2)2] (C8H7O2) · 2H2O, has been synthesized and characterized by single crystal X-ray structure determination. This is the first example of a cobalt(III) compound of this type with two p-methylbenzoate groups in cis-configuration. The cations and anions are associated in chains by strong NH … O hydrogen bonds. The crystal lattice is stabilized by extensive hydrogen bonding besides electrostatic forces of attraction.