Homochiral, Helical Coordination Complexes of Lanthanides(III) and Mixed-Metal Lanthanides(III): Impact of the 1,8-Naphthalimide Supramolecular Tecton on Structure, Magnetic Properties, and Luminescen
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- 作者：Daniel L. Reger ; Andrew Leitner ; Mark D. Smith
- 刊名：Crystal Growth & Design
- 出版年：2015
- 出版时间：November 4, 2015
- 年：2015
- 卷：15
- 期：11
- 页码：5637-5644
- 全文大小：429K
- ISSN：1528-7505
文摘
The reactions of the lithium salt of (S)-2-(1,8-naphthalimido)-3-hydroxypropanoate (Lserp>鈥?/sup>), an enantiopure carboxylate ligand containing a 1,8-naphthalimide 蟺路路路蟺 stacking supramolecular tecton and an alcohol functional group, with La(NO3)3, Ce(NO3)3, SmCl3, Eu(NO3)3, Gd(NO3)3, Tb(NO3)3, and Dy(NO3)3 under solvothermal conditions (water/ethanol) produced single crystals (characterized by single-crystal X-ray crystallography) of [La3(Lser)8(OH)(H2O)]路(H2O,EtOH)x (1), [Ce3(Lser)8(OH)(H2O)]路(H2O,EtOH)x (2), [Sm3(Lser)8(OEt)]路(H2O,EtOH)x (3), [Eu3(Lser)8(OEt)]路(H2O,EtOH)x (4), [Gd3(Lser)8(OEt)]路(H2O,EtOH)x (5), [Tb3(Lser)8(OEt)]路(H2O,EtOH)x (6), and [Dy3(Lser)8(OEt)]路(H2O,EtOH)x (7), respectively. Mixed-metal complexes [Ce2.3Tb0.7(Lser)8(OH)]路(H2O,EtOH)x (8), [Gd0.4Tb2.6(Lser)8(OEt)]路(H2O,EtOH)x (9), and [Ce1.4Gd0.3Tb1.3(Lser)8(OH)]路(H2O,EtOH)x (10) were prepared by using two or more types of lanthanides in the solvothermal reactions (additional mixed-metal complexes were prepared and characterized by ICP-MS). Single crystals of compounds 1鈥?b>10 are isostructural: trinuclear, carboxylate-bonded helicates organized by the non-covalent, 蟺路路路蟺 stacking interactions of the 1,8-naphthalimide groups into intertwined M helices, with a pitch of 56 脜, that are further arranged into a three-dimensional supramolecular framework by additional 蟺路路路蟺 stacking interactions. Magnetic measurements of several compounds were as expected for the metal(s) present, indicating no significant interactions between metals within the helicates. The Ce complex 2 showed weak antiferromagnetic ordering below 50 K. All of the complexes, with the exception of 2, showed luminescence based on the 1,8-naphthalimide group. Complex 2 has no emission, and complexes with mixed Ce/Tb ratios showed significant quenching of the naphthalimide-based luminescence, as quantitated with solid-state, absolute quantum yield measurements of these mixed-metal and the pure metal complexes. Lanthanide-based luminescence was only observed for the Eu complex 4.