Resumen: Reactions of Co(OH) 2 with the Schiff base bis(2-hydroxy-3-methoxybenzylidene)ethylenediamine, denoted H 2 (o-van-en), under different conditions yielded the previously reported complex aqua[bis(3-methoxy-2-oxidobenzylidene)ethylenediamine]cobalt(II), [Co(C 18 H 18 N 2 O 4 )(H 2 O)], 1, under anaerobic conditions and two polymorphs of [µ-bis(3-methoxy-2-oxidobenzylidene)ethylenediamine]bis{[bis(3-methoxy-2-oxidobenzylidene)ethylenediamine]cobalt(III)} acetonitrile tetrasolvate, [Co 2 (C 18 H 18 N 2 O 4 ) 3 ]·4CH 3 CN, i.e. monoclinic 2 and triclinic 3, in the presence of air. Both novel polymorphs were chemically and spectroscopically characterized. Their crystal structures are built up of centrosymmetric dinuclear [Co 2 (o-van-en) 3 ] complex molecules, in which each Co III atom is coordinated by one tetradentate dianionic o-van-en ligand in an uncommon bent fashion. The pseudo-octahedral coordination of the Co III atom is completed by one phenolate O and one amidic N atom of the same arm of the bridging o-van-en ligand. In addition, the asymmetric units of both polymorphs contain two acetonitrile solvent molecules. The polymorphs differ in the packing orders of the dinuclear [Co 2 (o-van-en) 3 ] complex molecules, i.e. alternating ABABAB in 2 and AAA in 3. In addition, differences in the conformations, the positions of the acetonitrile solvent molecules and the pattern of intermolecular interactions were observed. Hirshfeld surface analysis permits a qualitative inspection of the differences in the intermolecular space in the two polymorphs. A knowledge-based study employing Full Interaction Maps was used to elucidate possible reasons for the polymorphism. Idioma: Inglés DOI: 10.1107/S2053229619003115 Año: 2019 Publicado en: Acta Crystallographica Section C-Structural Chemistry C75 (2019), 433-442 ISSN: 2053-2296 Factor impacto JCR: 1.09 (2019) Categ. JCR: CRYSTALLOGRAPHY rank: 19 / 26 = 0.731 (2019) - Q3 - T3 Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 139 / 177 = 0.785 (2019) - Q4 - T3 Factor impacto SCIMAGO: 0.262 - Condensed Matter Physics (Q3) - Materials Chemistry (Q3) - Medicine (miscellaneous) (Q3) - Physical and Theoretical Chemistry (Q4) - Inorganic Chemistry (Q4)