Naked-eye detection and thermochromic properties of Cu(ii)-3,3′-thiodipropionate complexes with benzimidazole

Abstract

Two new coordination complexes, namely, [Cu(tdp)(H2O)(bim)3]·4H2O (1) and {[Cu(μ2-tdp)(bim)2]·4H2O}n (2) (tdp = 3,3'-thiodipropionate, bim = benzimidazole), having naked-eye sensor properties and thermochromic behaviors, were synthesized and structurally characterized using elemental analysis, IR and UV spectra, and single-crystal X-ray diffraction, powder X-ray diffraction (PXRD) and thermal analyses (TG, DTA and DTG) techniques. Complex 1 changed color from blue to dark and light green in methanol and DMF solvents, respectively, while complex 2 changed color from light blue to light green only in DMF solvent. Moreover, complex 1 can be used to detect as little as 10 percent methanol in ethanol by the naked eye. The thermochromic properties of the complexes showed that complexes 1 and 2 changed color from blue and light blue to light and dark green at 65 °C, respectively.

Thermochromic Behavior of Azobenzene‐based Coordination Polymer with Reversible Breathing Process

“…Such reversible color‐switch can be trigged several cycles without a noticeable color loss. This phenomenon indicates that the guest water molecules in 1 might play a critical role in the thermochromic behavior …”

“…The samples also displayed similar reversible breathing behavior after vacuum freeze drying. As mentioned above, the amount of hydrogen bonds in the structure might prevent the framework from collapsing after the dehydration ,. When the sample of 1 was further heated to higher temperatures, the framework collapsed due to the loss of bridging water molecules (Figure S3 and S4).…”

“…The results showed that the IR spectra were the same compared with that of the as‐synthesized complex 1 , except the absence of the broad and strong υ(OH) band at ca. 3324 cm −1 , indicating that water molecules within the structure were removed ,. As shown in Table , we also check the lattice parameter of the crystals (water‐free), which shows a slight expansion than that of 1 , expands by 1.16% along a axis, 1.04% along b , and 1.02% along c and shrinks to its origin size upon exposing the crystal to moisture.…”

“…Besides, we also measured the photochromic of 1 , no obvious color change was observed between before and after irradiation, which might be attributed to the strong localized energy of crystal lattice of 1 restricts the azobenzene isomerization effect, compare with the traditional azobenzene‐derivates MOFs . According to the above results and discussion, we suppose that the reversible thermochromic behavior might be ascribed to the change of the coordination environment of Zn 2+ ions with the loss of the lattice water and terminal water molecules at different temperatures . The thermochromic or hydrochromic behaviors are based on the processes of dehydration and rehydration and the thermochromic processes are reversible for sample 1 .…”

Syntheses and photoluminescence properties of new Zn(II) and Cd(II) coordination polymers prepared from 5-sulfoisophthalate ligand

“…5-Sulfoisophthalic acid (sipH 3 ) is one such interesting ligand and has two functional groups, -SO 3 H and -COOH. Partly or fully deprotonated sipH 2− and sip 3− are useful building blocks for constructing coordination polymers and act as a versatility ligand and coordinate to metal ions as bridging ligand.…”