A series of lead(II)/iodine hybrid polymers based on 1-D and 2-D metal–organic motifs linked by different organic conjugated ligands

Abstract

The introduction of series of organic conjugated ligands into the Pb/I system leads to the formation of three lead(II)/iodine polymers [Pb₂I₄(dpdo)]_n (1) (dpdo = 4,4′-dipyrdiyl-N,N′-dioxide), [PbI₂(bipyO₂)]_n (2) (bipyO₂ = 2,2′-dipyrdiyl- N,N′-dioxide) and {[PbI(Dhydql)]∙DMF}_n (3) (Dhydql = deprotonated 8-hydroxyquinoline). In 1 and 2, both the organic and inorganic ligands are neutral. But the organic moiety in 3 is a conjugated negative ion and the inorganic component presents a 2-D layer arrangement. The organic ligands in this work serve as bridges to link the inorganic chain or layer to heighten the structural dimension. As expected, based on the bridge nature of an organic ligand, 1 features a 2-D arrangement of a staircase-like lattice sheet [Pb₂I₄(dpdo)]_n, 2 exhibits a 1-D chain [PbI₂(bipyO₂)]_n consisting of unprecedented twisted boat from seven-membered rings, and 3 presents a host–guest structure with DMF as guest molecules which are embedded in between adjoining inorganic–organic components. Furthermore, the compounds were further characterized with fluorescence, UV-vis spectra and third-order non-liner optical (NLO) properties.