Two polymorphs of zinc(ii) coordination polymers constructed from 2-carboxyethyl(phenyl)phosphinate and 1,4-bis(1H-imidazol-1-yl)butane ligands

Abstract

Two coordination polymeric polymorphs of [Zn(BIB)_0.5L]_n (BIB = 1,4-bis(1H-imidazol-1-yl)butane; L²⁻ = 2-carboxyethyl(phenyl)phosphinate) have been synthesized and crystallographically characterized. The two true polymorphs show distinguishable structures: one has a 2D ladder-like structure that is constructed from BIB bridging ligands and double sawtooth chain units composed of Zn(II) centers and L²⁻ ligands, while the other is a 3D framework, in which two-dimensional corrugated sheets constructed from Zn(II) ions and L²⁻ are pillared by BIB ligands. These two polymorphs, which mainly resulted from the different intramolecular propagations generated by the distinct symmetry codes, are very rare in coordination polymers. The photoluminescence behaviors and thermal stabilities of two complexes are also presented.