Crystal structures and Hirshfeld surface analysis of -bis-(thio-cyanato-κ)bis-{2,4,6-trimethyl--[(pyridin-2-yl)methyl-idene]aniline-κ ,'}manganese(II) and -bis-(thio-cyanato-κ)bis-{2,4,6-trimethyl--[(pyridin-2-yl)methyl-idene]aniline- ,'}nickel(II)).

Two new mononuclear metal complexes involving the bidentate Schiff base ligand 2,4,6-trimethyl--[(pyridin-2-yl)methyl-idene]aniline (CHN or PM-TMA), [Mn(NCS)(PM-TMA)] () and [Ni(NCS)(PM-TMA)] (), were synthesized and their structures determined by single-crystal X-ray diffraction. Although the title compounds crystallize in different crystal systems [triclinic for () and monoclinic for ()], both asymmetric units consist of one-half of the complex mol-ecule, one metal(II) cation, one PM-TMA ligand, and one N-bound thio-cyanate anion. In both complexes, the metal(II) cation is located on a centre of inversion and adopts a distorted octa-hedral coordination environment defined by four N atoms from two symmetry-related PM-TMA ligands in the equatorial plane and two N atoms from two symmetry-related NCS anions in a axial arrangement. The tri-methyl-benzene and pyridine rings of the PM-TMA ligand are oriented at dihedral angles of 74.18 (7) and 77.70 (12)° for () and (), respectively. The subtle change in size of the central metal cations leads to a different crystal packing arrangement for () and () that is dominated by weak C-H⋯S, C-H⋯π, and π-π inter-actions. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to qu-antify these inter-molecular contacts, and indicate that the most significant contacts in packing are H⋯H [48.1% for () and 54.9% for ()], followed by H⋯C/C⋯H [24.1% for () and 15.7% for ()], and H⋯S/S⋯H [21.1% for () and 21.1% for ()].