Acentric and chiral heterometallic inorganic–organic hybrid frameworks mediated by alkali or alkaline earth ions: synthesis and NLO properties

The rapid development in inorganic–organic hybrid frameworks has enabled the discovery of many structurally fascinating and technologically useful materials. The design of such hybrid crystals with noncentrosymmetric frameworks is particularly important because of their interesting electronic and optical properties. Several synthetic approaches, including the use of chiral and unsymmetric ligands, or spontaneous resolution via using achiral building blocks, have been applied to facilitate the formation of acentric and chiral hybrid materials. In this highlight, we will review another way to increase the chance of obtaining acentric and chiral frameworks by adding alkali or alkaline earth metals into heterometallic systems. The synthesis of these frameworks is discussed along with their potential NLO properties.