Designing Geometric Degrees of Freedom in ReO ₃ ?Type Coordination Polymers

Engineering the interplay of structural degrees freedom that couple to external stimuli such as temperature and pressure is a powerful approach for material design. New expand potential concept, coordination polymers chemically versatile platform offer fascinating possibilities address this challenge. Here, we report new class perovskite-like AB2X6 based on [BX3] ? ReO3-type host network ([Mn(C2N3)3] ?), in which spatial orientation divalent A2+ cations ([R3N(CH2)nNR3]2+) with separated charge centers bridge adjacent ReO3-cavities introduced geometric degree freedom. Herringbone head-to-tail order pattern [R3N(CH2)nNR3]2+ are obtained by varying separator length n and, together distortions pseudocubic network, they determine materials’ stimuli-responsive behavior counterintuitive large negative compressibility uniaxial thermal expansion. This family highlights chemists’ capabilities designing matter molecular level macroscopic functionality underpins opportunities design conceptual framework rational synthesis future.