Novel Metallo-Supramolecular Architectures Based on Side-Pyridine-Modified Terpyridines: Design, Self-assembly, and Properties

2,2':6',2''-terpyridine (tpy), as a classical tridentate chelating ligand, has been extensively utilized to construct discrete metallo-supramolecular architectures. However, current research has predominantly focused on conventional modification strategies at the 4'-position of the central pyridine ring. Recent breakthroughs in synthetic methodologies for side-pyridine functionalization have given rise to a new generation of tpy-based metallo-supramolecular systems. These innovative achievements have transcended the limitations of traditional design paradigms by significantly improving the coordination selectivity of terpyridine systems, thereby substantially expanding both the structural diversity and functional dimensionality of tpy-based coordination chemistry. This review systematically summarizes recent advances in novel side-pyridine-modified tpy-based coordination supramolecular architectures, including mononuclear complexes, helicates, two-dimensional (2D) macrocycles and polygons, three-dimensional (3D) cages and polyhedra, and decker architectures. A comprehensive discussion is provided on the functional implementations of these systems across various domains, particularly highlighting their applications in luminescence, catalysis, chirality, host-guest chemistry, and hierarchical self-assembly.