Intermolecular Interaction and Magnetic Coupling Mechanism of a Mononuclear Nickel(II) Complex

Abstract

AbstractThe mononuclear complex [Ni(HOphen)(OSO3)(H2O)3]·5H2O (HOphen = 1, 10‐phenanthrolin‐2‐ol) was prepared and its single structure was determined by X‐ray crystallography. In this complex, the NiII ion has a distorted octahedral arrangement. Crystal structure analysis shows that two kinds of π–π stacking interactions and C–H···O short contact intermolecular interactions exist among the adjacent complexes. Fitting to the variable‐temperature magnetic susceptibility data gave the magnetic coupling constant, 2J = –0.98 cm–1. Theoretical calculations, based on density functional theory (DFT) coupling with the broken‐symmetry approach (BS), revealed that the π–π stacking magnetic coupling pathways resulted in weak ferromagnetic interactions with 2J = 4.86 cm–1 and 2J = 4.16 cm–1, respectively, for the adjacent NiII ions with separations of 8.568(19) Å and 8.749(32) Å, respectively; whereas the magnetic coupling pathway of the C–H···O short contact intermolecular interaction led to a weak antiferromagnetic interaction with 2J = –17.62 cm–1 for the adjacent NiII ions with a separation of 10.291(26) Å. The ferromagnetic coupling sign can be explained by the McConnell I spin‐polarization mechanism.