Series of Cd(II) Metal–Organic
Frameworks Based
on a Flexible Tripodal Ligand and Polycarboxylate Acids: Syntheses,
Structures, and Photoluminescent Properties
- Publication date
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Abstract
Five novel metal–organic frameworks with a 1,3,5-tris(triazol-1-ylmethyl)-2,4,6-trimethylbenzene
(tttmb) flexible tripodal block, namely, {[Cd(tttmb)(atc)]·1.5H<sub>2</sub>O}<i><sub>n</sub></i> (<b>1</b>), {[Cd<sub>5</sub>(tttmb)<sub>2</sub>(tbi)<sub>5</sub>(H<sub>2</sub>O)<sub>4</sub>]·2H<sub>2</sub>O}<i><sub>n</sub></i> (<b>2</b>), {[Cd<sub>3</sub>(tttmb)<sub>2</sub>(bdc)<sub>3</sub>(H<sub>2</sub>O)<sub>3</sub>]·0.5H<sub>2</sub>O}<i><sub>n</sub></i> (<b>3</b>), {[Cd<sub>2</sub>(tttmb)<sub>2</sub>(btc)Cl]·3H<sub>2</sub>O}<sub><i>n</i></sub> (<b>4</b>), and {[Cd<sub>2</sub>(tttmb)<sub>2</sub>(btec)(H<sub>2</sub>O)<sub>3</sub>]·H<sub>2</sub>O}<sub><i>n</i></sub> (<b>5</b>) (H<sub>2</sub>atc = 1,3-adamantanedicarboxylic acid, H<sub>2</sub>tbi = 5-<i>tert</i>-butylisophthalic acid, H<sub>2</sub>bdc = 1,4-benzenedicarboxylic
acid, H<sub>3</sub>btc = 1,2,4-benzenetricarboxylic acid, and H<sub>4</sub>btec = 1,2,4,5-benzenetetracarboxylic acid), have been synthesized.
Complex <b>1</b> exhibits a two-dimensional structure with left-
and right-handed helical chains arranged alternately. Complex <b>2</b> displays an intricate two-dimensional framework containing
three layers with a 3,4,7-connected topology. It is notable that tbi<sup>2–</sup> takes on five different coordination modes in <b>2</b>. Complex <b>3</b> presents a 3D 3,4-connected network
with a point symbol of (6<sup>3</sup>)<sub>2</sub>(6<sup>4</sup>·8<sup>2</sup>)<sub>2</sub>(6<sup>3</sup>·8<sup>3</sup>). The structure
of complex <b>4</b> is a self-penetrating 3D 3,4,8-connected
framework with left- and right-handed helical chains arranged alternately.
Complex <b>5</b> shows a 3D pillar-layered framework, which
can be simplified as a 3,4,5-connected 3D topology with a Schläfli
symbol of (5<sup>3</sup>)(5<sup>2</sup>·6<sup>2</sup>·7·9)(5<sup>5</sup>·6<sup>2</sup>·7<sup>2</sup>·8). Moreover,
the investigation of photoluminescence properties reveals that complexes <b>1</b>–<b>5</b> show different fluorescent behaviors
