Ionothermal syntheses, crystal structures and properties of three-dimensional rare earth metal-organic frameworks with 1,4- naphthalenedicarboxylic acid

摘要

Twelve isostructural rare earth metal-organic frameworks, namely, [Hmim][RE _2Cl(1,4-NDC) _3] (RE = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Ho (10), Er (11), Y (12), Hmim = 1-hexyl-3-methylimidazolium, 1,4-NDCH _2 = 1,4-naphthalenedicarboxylic acid), have been ionothermally synthesized and structurally characterized. The structures feature three-dimensionally anionic frameworks of [RE _2Cl(1,4-NDC) _3] _n ~(n-) with channels in which the Hmim ~+ cations are located. The current results are the first ionothermal synthesis of rare earth metal-organic frameworks based on 1,4-NDCH _2 which possess a previously unknown (4,7)-connected 3-nodal network with the Schl?fli symbol of (3 ~2·4 ~2·5 ~2)(3 ~2·4 ~9· 5 ~2·6 ~8) _2(4 ~3·6 ~3) _2. Luminescent and magnetic properties of some of the title compounds have been studied. Thermogravimetric analyses indicated that all these compounds were thermally stable up to ca. 250 °C.