doi:10.1016/j.molstruc.2025.142198engSmolko, RichardFalvello, Larry R.Ara, IreneTitiš, JánBoca, RomanCernák, JurajPentacoordinate Ni(II) complex: Synthesis, crystal structure and magnetismART-2025-143772Ni(II) complex [Ni(na-dmdpa)] (H2(na-dmdpa) = 1,1′-((1E,1′E)-(((methylazanediyl)bis(propane-3,1iyl))bis(azaneylylidene))bis(methaneylylidene))bis (naphthalen-2-ol) has been synthesized using Schiff-base type pentadentate ligand formed by condensation of 2-hydroxynaphthaldehyde with 3,3ˈ-diamino-N-methyldipropylamine. The crystal structure is built up of complex molecules [Ni(na-dmdpa)]. The Ni(II) centre exhibits pentacoordination and its coordination sphere is formed by deprotonated Schiff base acting as doubly chelating pentadentate dianionic ligand. Calculated τ value for complex [Ni(na-dmdpa)] indicates that the coordination polyhedron is an intermediate between trigonal bipyramid and square pyramid. Complex is stable at RT. From the magnetic study follows that the axial zero-field splitting parameter is significantly negative (D/hc = –51 cm-1) and the value of rhombicity is moderate (E/hc = 2.4 cm-1). Theoretical calculations support the magnetic experimental result. The out-of-phase component of the AC susceptibility is silent.2025http://zaguan.unizar.es/record/16303410.1016/j.molstruc.2025.142198http://zaguan.unizar.es/record/163034oai:zaguan.unizar.es:163034JOURNAL OF MOLECULAR STRUCTURE 1337 (2025), 142198by-nc-ndhttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.esinfo:eu-repo/semantics/embargoedAccess