Molecular transition-metal–ligand complexes are emerging as useful paradigms in materials science. Transition metal complexes have diverse metal d electron configurations, oxidation states, coordination numbers and geometries such that they can undergo a diverse array of electronic transitions. Metal-to-ligand charge-transfer transitions and their associated excited states are especially attractive given their rich redox properties and robustness. This chemistry is accessible by appropriate choice of low-valence metal centres and strong π-acceptor ligands. An in-depth fundamental understanding of their charge-transfer, assembly and structure–property relationships is important to allow us to rationally design complexes and tune their characteristics for an intended application. In addition to their attractive light-harvesting and photocatalytic applications, this Perspective describes recent developments in the use of transition metal complexes as materials in phosphorescent organic light-emitting diodes and resistive memory devices.

分子过渡金属-配体配合物在材料科学中正在成为有用的范例。过渡金属配合物具有不同的金属d电子构型，氧化态，配位数和几何形状，以便它们可以经历各种各样的电子跃迁。金属到配体的电荷转移跃迁及其相关的激发态因其丰富的氧化还原特性和坚固性而特别引人注目。这种化学是低价的金属中心的合适的选择和强大的π受体配体的访问。对它们的电荷转移，组装和结构-性质关系的深入基础了解对于使我们能够合理地设计配合物并针对预期的应用调整其特性非常重要。除了吸引人的光收集和光催化应用之外，