A-Site Cation Template-Induced N–H···O Hydrogen-Bond Orientations for Constructing Three-Dimensional Cesium-Based Energetic Molecular Perovskites

Abstract

Energetic molecular perovskites (EMPs) are a high-energy subclass of molecular perovskites that integrate oxidizers and fuels within a single framework. However, the structures of reported EMPs remain rather limited, and the structural contribution and governing role of their component ions remain elusive. Herein, we develop an A-site cation-templated strategy to direct the spatial orientation of N–H···O hydrogen bonds, enabling the rational engineering of two Cs-based EMPs with distinct 3D frameworks: trigonal DCP-1 and tetragonal TCP-1. The inductive effect of the A-site cation in framework construction is elucidated. Unlike H2hmta2+, H2dabco2+ features a unique parallel N–H vector field, which drives the connection of [Cs(ClO4)6] octahedra through a rare alternating face-sharing and corner-sharing mode. This assembly results in the first EMP crystallizing in the R3̅c space group. Such structural divergence, governed by the spatial orientation of hydrogen bonds, leads to a significant differentiation in physicochemical properties. This work not only introduces cesium into EMPs for the first time but also expands the structural diversity of EMPs by introducing an unusual trigonal framework. The universal principle of tailoring crystal structures and energetic properties by A-site hydrogen-bond vectors is revealed, providing insights into next-generation high-performance energetic materials.