Carboxylate-Ligand-Based Coordination Polymers and Metal Complexes: From Structural Diversity and Supramolecular Descriptors to Function-Oriented Design

Abstract

Carboxylate-ligand-based coordination polymers and metal complexes form structurally adaptable crystalline systems, spanning discrete complexes, one-dimensional chains, two-dimensional layers, three-dimensional frameworks, and MOF-like architectures. This adaptability arises from diverse carboxylate binding modes and metal coordination preferences; auxiliary N/O donors are included only when carboxylate coordination remains central. However, the increasing availability of structural and electronic descriptors has not always been matched by equally rigorous validation of structure–function relationships. Hirshfeld surface analysis, energy-framework analysis, density functional theory, adsorption simulation, molecular docking, and machine learning are descriptor-generating methods; neither a method nor its output alone establishes descriptor-guided design. This review critically examines carboxylate-based coordination systems from the perspective of descriptor-guided function-oriented design. We discuss ligand-level regulation, metal-center effects, dimensional evolution, and what supramolecular, electronic, adsorption-related, and biological descriptors can and cannot prove. Functional studies covering luminescence and sensing; catalysis, adsorption, and small-molecule transformations; and bioactivity are evaluated by evidence strength. A claim-centered Descriptor-to-Function Evidence Ladder distinguishes structure reporting, descriptive descriptor use, post hoc association, controlled comparative trends, mechanism-supported validation, and prospective experimental confirmation. It evaluates a specific descriptor–function relationship rather than overall paper quality. Future progress should rely on standardized reporting, comparative structural series, function-specific validation, and transferable descriptor–function relationships.