Cocrystallization of coordinative and inorganic lanthanide centers showing dual emission via linked or unlinked antenna
作者:Kang Li、Yu Liu、Cheng Yan、Lei Fu、Shi-Chao Wei、Hai-Ping Wang、Mei Pan、Cheng-Yong Su
DOI:10.1039/c2ce06605j
日期:——
In this paper, we report the design and synthesis of two pyridyl-substituted tripodal ligands, 3-TPyMNTB (tris(((pyridin-3-ylmethyl)benzimidazol-2-yl)methyl)amine) and 4-TPyMNTB (tris(((pyridin-4-ylmethyl)benzimidazol-2-yl)methyl)amine). Reaction of these two ligands with Eu(III)/Tb(III) picrate salts gives mononuclear complexes [Eu(3-TPyMNTB)(pic)3]·2H2O (1) and [Tb(3-TPyMNTB)(pic)3]·2H2O (2), respectively. While reaction with Eu(III)/Tb(III) nitrate salts leads to cocrystallization of a coordinative motif and an inorganic salt in one single-crystal, namely, [Eu(3-TPyMNTB)(NO3)3]·0.5[Eu(NO3)3(H2O)4]·3CH3CN (3), [Tb(3-TPyMNTB)(NO3)3]·0.5[Tb(NO3)3(H2O)4]·3CH3CN·1.5C2H5OH (4), [Eu(4-TPyMNTB)(NO3)3]·[Eu(NO3)3(H2O)3]·3CH3CN·0.5H2O (5) and [Tb(4-TPyMNTB)(NO3)3]·[Tb(NO3)3(H2O)3]·3CH3CN·0.5H2O (6). In these cocrystals, the organic ligand-coordinated motif [Ln(3(4)-TPyMNTB)(NO3)3] and the nitrate anion-bonded motif [Ln(NO3)3(H2O)n] (Ln = Eu(III) or Tb(III), n = 3 or 4) provide two Eu(III)/Tb(III) centers which coexist in the same crystal lattice. Of most interest, both coordinative and inorganic centers can be excited by the absorption of the organic ligand, that is, the double luminescent centers in the cocrystalline systems can be sensitized by the same antenna source. Therefore, both Dexter and Förster mechanisms are proposed to be involved in the emission process, in which the energy transfer is conducted either through direct bond linkages or through space from unlinked organic antennae.
本文报告了两种吡啶基取代的三足配体--3-TPyMNTB(三(((吡啶-3-基甲基)苯并咪唑-2-基)甲基)胺)和 4-TPyMNTB(三(((吡啶-4-基甲基)苯并咪唑-2-基)甲基)胺)的设计和合成。这两种配体与 Eu(III)/Tb(III)苦味酸盐反应,分别得到单核配合物 [Eu(3-TPyMNTB)(pic)3]-2H2O (1) 和 [Tb(3-TPyMNTB)(pic)3]-2H2O (2)。与 Eu(III)/Tb(III)硝酸盐反应会导致配位基团和无机盐在一个单晶中结晶,即[Eu(3-TPyMNTB)(NO3)3]-0。5[Eu(NO3)3(H2O)4]·3CH3CN (3), [Tb(3-TPyMNTB)(NO3)3]·0.5[Tb(NO3)3(H2O)4]·3CH3CN·1.5C2H5OH(4)、[Eu(4-TPyMNTB)(NO3)3]-[Eu(NO3)3(H2O)3]-3CH3CN-0.5H2O(5)和[Tb(4-TPyMNTB)(NO3)3]-[Tb(NO3)3(H2O)3]-3CH3CN-0.5H2O(6)。在这些共晶体中,有机配位体配位基团[Ln(3(4)-TpyMNTB)(NO3)3]和硝酸盐阴离子键基团[Ln(NO3)3(H2O)n](Ln = Eu(III)或 Tb(III),n = 3 或 4)提供了两个共存于同一晶格中的 Eu(III)/Tb(III) 中心。最令人感兴趣的是,配位中心和无机中心都能被有机配体的吸收所激发,也就是说,共晶体系中的双发光中心能被同一天线源敏化。因此,德克斯特机制和福斯特机制都被认为参与了发射过程,其中的能量转移是通过直接的键连接或通过未连接的有机天线的空间进行的。