Syntheses, structures and luminescence properties of lanthanide coordination polymers with helical character

A series of lanthanide coordination polymers, (Him)n[Ln(ip)2(H2O)]n [Ln=La(1), Pr(2), Nd(3) and Dy(4), H2ip=isophthalic acid, im=imidazole] and [Y2(ip)3(H2O)2]n·nH2O (5), have been synthesized and characterized by elemental analyses, infrared (IR), ultraviolet-visible-near infrared (UV-Vis-NIR) and single-crystal X-ray diffraction analyses. The isostructural compounds 1–4 possess 3-D structures with three different kinds of channels. Compound 5 features a 2-D network making of two different kinds of quadruple-helical chains. Compounds 2 and 3 present the characteristic emissions of Pr(III) and Nd(III) ions in NIR region, respectively. Compound 4 shows sensitized luminescence of Dy(III) ions in visible region.