Synthetic Control of Structure and Magnetism in Low-Dimensional Organic Copper(II) Chloride Hybrids.

Low-dimensional (LD) organic metal halide hybrids (OMHHs) have attracted widespread attention owing to their exceptional structural versatility and emergent photophysical and spin-dependent properties. While hundreds of LD OMHHs have been reported to date, systematic investigations into how organic cations influence structural dimensionality and magnetic behavior remain limited. Here, we report a steric-engineering strategy to control structural dimensionality and magnetism in LD OMHHs. By systematically tuning methyl substitution in 1,3-propanediamine (PDA), we achieve a structural progression from two-dimensional (2D) Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) phases to a mixed one-dimensional/zero-dimensional (1D/0D) structure, and ultimately isolated 0D structures in a series of organic copper(II) chloride hybrids. This structural evolution modulates magnetic exchange pathways, giving rise to coexisting ferromagnetic (FM) and antiferromagnetic (AFM) interactions in 2D OMHHs, dual AFM transitions in the mixed-dimensional (MD) system, and paramagnetic (PM) behavior in 0D compounds. Density functional theory (DFT) calculations reveal spin configurations consistent with experimentally observed magnetic behavior. This work presents a unique approach to precisely controlling the dimensionality and magnetism of OMHHs, paving the way for the rational design of ionically bonded organic-inorganic hybrid materials for spintronic applications.