Structure Guiding Supramolecular Assemblies in Metal-Organic Multi-Component Compounds of Mn(II): Experimental and Theoretical Studies

Two multi-component coordination compounds of Mn(II), viz. [Mn(H2O)6](2-Mepy)2(4-NO2bz)2·2H2O (1) and [Mn(H2O)6][Mn(2,3-PDCH)3]2 (2) (where, 2-Mepy = 2-methylpyridine, 4-NO2bz 4-nitrobenzoate, 2,3-PDC 2,3-pyridinedicarboxylate), have been synthesized characterized using elemental, spectroscopic (FT-IR electronic), TGA single-crystal X-ray diffraction analyses. Complex 1 is a co-crystal hydrate Mn(II) involving uncoordinated 2-Mepy, water molecules; while compound 2 molecular complex salt comprising cationic [Mn(H2O)6]2+ anionic [Mn(2,3-PDCH)3]−complex moieties. The moieties are involved in lone-pair (l.p)-π C–H⋯π interactions which stabilize the layered assembly compound. crystal structure has previously reported. However, we explored unusual enclathration within supramolecular host cavities formed by assemblies obtained further studied theoretically DFT calculations, quantum theory atoms-in-molecules (QTAIM) non-covalent interaction plot (NCI plot) computational tools. Theoretical studies reveal that combination π-staking (l.p-π, π-π C–H···π) more structure-guiding roles compared to H-bonds. large binding energy π-stacking due antiparallel orientation aromatic rings their metal centers, thereby increasing contribution dipole–dipole interactions.