Multifunctional polymetallaynes: properties, functions and applications

Insertion of transition metal elements into organic polymeric scaffolds enables a nice coupling of the intriguing physical traits of metal complexes such as electronic, optical and magnetic properties with the solution processability of carbon-based macromolecules. The propensity of these metal-based polymers towards exhibiting metal-metal interactions can also provide additional means for manipulating the structural order and electronic coupling in the molecules. Among these metallopolymers, rigid-rod transition metal σ-acetylide polymers, or polymetallaynes in short, are of much current interest. These organometallic polymers are important functional materials showing unique characteristics including electrical semiconductivity, photo-/electroluminescence, non-linear optical properties, liquid crystallinity, chemosensing capability and photovoltaic effect. Recently, there has been an impressive progress of functional polymetallaynes consisting of a variety of conjugated organic bridging moieties and transition metals. In this review, we summarize the structure-property-function relationships of polymetallaynes of different transition metals, with a major focus on the effect of transition metals and the structural modification of ligands in activating their multifunctional properties. Different emerging applications can thus be realized, for example, as the converters for both light/electricity signals, sensor protectors against intense laser beam and patternable precursors to magnetic metal alloy nanoparticles for data storage, etc.