A New Coordination Polymer Exhibiting Unique 2D Hydrogen‐Bonded (H₂O)₁₆ Ring Formation and Water‐Dependent Luminescence Properties

Abstract

A new coordination polymer, [Zn(dpe)(bdc)]·4H(2)O (ZndB; dpe=1,2-bis(4-pyridyl)ethane, bdc(2-)=dianion of benzenedicarboxylic acid), which possesses a 3D metal-organic framework (MOF) has been synthesized and structurally characterized. This 3D MOF is constructed by the assembly of helical channels filled with guest water molecules in both inner and outer regions of the channel. The resulting network also creates a 2D water layer containing hydrogen-bonded (H(2)O)(16) rings as the basic building units. Thermogravimetric and powder X-ray diffraction measurements of ZndB revealed a two-step weight loss of water molecules with a reversible water adsorption/desorption process in the inner channel for the first stage, and irreversible water desorption in the outer channel for the second stage. This spongelike property is manifested by the excimer emission originating from interaction between dpe (π*) and the other dpe (π) of the proximal helical channel, which is highly sensitive to the environmental perturbation. Powder X-ray analyses reveal that the dehydration process induces the readjustment of dpe π-π stacking distance/orientation, which results in dramatic luminescence changes from dim pale blue (λ(em)≈470 nm) upon hydration to bright white-light generation (broad, λ(em)≈500-550 nm) upon water depletion, accompanied by a ≈100-fold increase in the emission intensity.

Supramolecular Open-Framework of a Bipyridinium-Carboxylate Based Copper Complex with High and Reversible Water Uptake

“…We must first notice that the water uptake is high for this compound and that the reached value [0.230 g(H 2 O) per g] is very close to the expected one if the initial hydrated phase is recovered [0.233 g(H 2 O) per g for 12 H 2 O per Cu]. It is worth noting that this water content is considerably higher than the amounts reported for other PSN (0.1–0.15 g per g) , , . The maximum uptake observed for Cu( pc1 ) 2 Cl 2 is thus comparable with the capacity of 3A molecular sieves (0.22 g per g) .…”

Photoluminescent Metal–Organic Frameworks for Gas Sensing

“…Wang et al reported a 3D MOF [Zn(dpe)(bdc)]·4H 2 O (dpe = 1,2‐bis(4‐pyridyl)ethane) which can show H 2 O‐dependent luminescence properties ( Figure 5 ). 86 This MOF is 5‐fold interpenetrated diamondoid network filled with 2D water layer containing hydrogen‐bonded (H 2 O) 16 rings. The as‐synthesized MOF showed a two‐step water removal with a reversible desolvated/resolvated process from 30 to 86 °C, giving a partially dehydrated phase [Zn(dpe)(bdc)]⋅2H 2 O, and an irreversible one from 195 to 250 °C.…”

“…In addition, useful information of structural transformation can also be obtained by using powder X‐ray diffraction (PXRD), being favorable for understand the sensing behavior. Wang et al reported a 3D MOF [Zn(dpe)(bdc)]·4H 2 O (dpe = 1,2‐bis(4‐pyridyl)ethane) which can show H 2 O‐dependent luminescence properties ( Figure ) . This MOF is 5‐fold interpenetrated diamondoid network filled with 2D water layer containing hydrogen‐bonded (H 2 O) 16 rings.…”

Synthesis, Crystal Structures, and Magnetic Properties of Three Cobalt(II) Coordination Polymers Constructed from 3,5-Pyridinedicarboxylic Acid or 3,4-Pyridinedicarboxylic Acid Ligands

“…The neighboring three Co atoms are bridged by six other L 2 ligands into a 2D hexagonal (6,3) network (Figure 3a) with hcb topology (Figure 3b) [32][33][34][35]. Furthermore, the adjacent layers are further linked into a 3D supramolecular architecture by π-π interactions between the 2,2-bipyridine molecules with center-to-center distances of 3.56-3.92 Å ( Figure S9) [36][37][38][39][40].…”