Anion-Directed Self-Assembly of Lanthanide–notp Compounds and Their Fluorescence, Magnetic, and Catalytic Properties
✍ Scribed by Song-Song Bao; Li-Fang Ma; Yin Wang; Ling Fang; Cheng-Jian Zhu; Yi-Zhi Li; Li-Min Zheng
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 685 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
Abstract
Reactions of 1,4,7‐triazacyclononane‐1,4,7‐triyl‐tris(methylenephosphonic acid) [notpH~6~, C~9~H~18~N~3~(PO~3~H~2~)~3~] with different lanthanide salts result in four types of Ln–notp compounds: [Ln{C~9~H~20~N~3~(PO~3~H)~2~(PO~3~)}(NO~3~)(H~2~O)]⋅4 H~2~O (1), [Ln = Eu (1 Eu), Gd (1 Gd), Tb (1 Tb)], [Ln{C~9~H~20~N~3~(PO~3~H)~2~(PO~3~)}(H~2~O)]Cl⋅3 H~2~O (2) [Ln = Eu (2 Eu), Gd (2 Gd), Tb (2 Tb)], [Ln{C~9~H~20~N~3~(PO~3~H)~2~(PO~3~)}(H~2~O)]ClO~4~⋅8 H~2~O, (3) [Ln = Eu (3 Eu), Gd (3 Gd)], and [Ln{C~9~H~20~N~3~(PO~3~H)~2~(PO~3~)}(H~2~O)]ClO~4~⋅3 H~2~O (4), [Ln = Gd (4 Gd), Tb (4 Tb)]. Compounds within each type are isostructural. In compounds 1, dimers of {Ln~2~(notpH~4~)~2~(NO~3~)~2~(H~2~O)~2~} are found, in which the two lanthanide atoms are connected by two pairs of O‐P‐O and one pair of μ‐O bridges. The NO~3~^−^ ion serves as a bidentate terminal ligand. Compounds 2 contain similar dimeric units of {Ln~2~(notpH~4~)~2~(H~2~O)~2~} that are further connected by a pair of O‐P‐O bridges into an alternating chain. The Cl^−^ ions are involved in the interchain hydrogen‐bonding networks. A similar chain structure is also found in compounds 3; in this case, however, the chains are linked by ClO~4~^−^ counterions through hydrogen‐bonding interactions, forming an undulating layer in the (011) plane. These layers are fused through hydrogen‐bonding interactions, leading to a three‐dimensional supramolecular network with large channels in the [100] direction. Compounds 4 show an interesting brick‐wall‐like layer structure in which the neighboring lanthanide atoms are connected by a pair of O‐P‐O bridges. The ClO~4~^−^ counterions and the lattice water molecules are between the layers. In all compounds the triazamacrocyclic nitrogen atoms are not coordinated to the Ln^III^ ions. The anions and the pH are believed to play key roles in directing the formation of a particular structure. The fluorescence spectroscopic properties of the Eu and Tb compounds, magnetic properties of the Gd compounds, and the catalytic properties of 4 Gd were also studied.