Multifunctional Polythreading Coordination Polymers: Spontaneous Resolution, Nonlinear‐Optic, and Ferroelectric Properties

The reactions of methylenediisophthalic acid (H 4 L) and N‐auxiliary ligands (1,2‐bis(4‐pyridyl)ethylene, 1,2‐bis(4‐pyridyl)ethane) with transition‐metal centers (Co 2+ /Mn 2+ ) have given rise to four unprecedented polythreading coordination polymers. Single‐crystal X‐ray diffraction analyses revealed that the compounds can be described as 3D 2− ⊂2[1D 2+ ]+2D 6− for 1 , 3D 4− ⊂1D 2+ +1D 6− for 2 , and 2D 4− ⊂0D 2+ +2[1D 3− ] for 3 and 4 . All the polymers are formed through the assembly of two kinds of motifs with opposite charges. Noncentrosymmetric structures and multifunctionality in 2 – 4 are established by varying ligands and metal centers. Spontaneous resolution upon crystallization occurred in compounds 3 and 4 in the absence of any chiral source. The enantiomers of 3 and 4 consist of three chiral building blocks of L 4− /HL 3− and Mn 2+ centers. In the solid state, polar compounds 2 – 4 exhibit nonlinear‐optic (NLO) and ferroelectric properties at room temperature. The assembly of two kinds of motifs with opposite charges provides a useful method for the preparation of multifunctional compounds.