A Family of Capsule-Based Coordination Polymers Constructed from a New Tetrakis(1,2,4-triazol-ylmethyl)­resorcin[4]arene Cavitand and Varied Dicarboxylates for Selective Metal-Ion Exchange and Luminescent Properties

A series
of novel capsule-based coordination polymers (CPs), namely, [Cd­(TTR4A)­(L1)]­·2.5H2O (1), [Cd­(TTR4A)­(L2)]­·2DMF­·2H2O (2), [Cd­(TTR4A)­(L3)]­·2DMF­·1.5H2O (3), [Cd­(TTR4A)­(L4)]­·1.5H2O (4), and [Zn­(TTR4A)­(L1)]­·DMF­·H2O (5), have been synthesized via the reaction
of a bowl-like tetrakis­(1,2,4-triazol-ylmethyl­resorcin[4]­arene
(TTR4A) ligand with d10 metal salts in the presence of
varied dicarboxylates (H2L1 = fumaric acid, H2L2 = 1,3-benzenedicarboxylic acid, H2L3 = 5-hydroxy-1,3-benzenedicarboxylic
acid, H2L4 = biphenylethene-4,4′-dicarboxylic acid,
and DMF = N,N-dimethylformamide).
CPs 1–3 show rare two-dimensional
(2D) capsule-based network structures. In 1–3, two TTR4A bowls share two Cd­(II) cations to give a capsule,
which is further extended by the dicarboxylates into 2D networks.
CP 4 features a fascinating three-dimensional 3-connected
framework structure constructed from bowl-like [Cd2TTR4A]
units and L4 anions. In 5, each TTR4A coordinates with
two Zn­(II) cations by using two 1,2,4-triazole groups to generate
a capsule, which is further connected by L1 ligands to afford a 2D
network structure. Significantly, solid-state emissions and temperature
variable luminescence were studied for 1–4. In particular, the remarkable metal-ion exchange property
of CP 1 was investigated.