A bi-metallic MOF catalyst via sensitive detection & adsorption of Fe³⁺ ions for size-selective reaction prompting

Abstract

A cadmium(ii)-based MOF, Cd-MDIP, was successfully prepared by hydrothermal reaction between the tetra-carboxylic ligand 5,5'-methylenebisophthalic acid (H4MDIP) and cadmium perchlorate. The X-ray crystal structure analysis showed that there are two uncoordinated carboxyl groups in each ligand and a 1D elliptical channel along the [001] direction. Because of the existence of uncoordinated carboxyl groups within open frameworks, Cd-MDIP exhibited a high sensitivity (Stern-Volmer constant KSV = 4.13 × 104 L mol-1) and a low detection limit (80 nM) for Fe3+ ions in pure water, which is much lower than the national standard for Fe3+ in daily drinking water (5.4 μM) set by the Ministry of Environmental Protection of P. R. China. Most importantly, Cd-MDIP also featured the ultrahigh adsorption of Fe3+ in aqueous solution that cannot be destroyed even by EDTA/base. Importantly, the MOF material (Cd-MDIP⊃Fe3+) after adsorbing Fe3+ could act as the first example of an excellent bi-metallic Lewis-acid catalyst for the cyanosilylation reaction of aromatic aldehydes in a size-selective fashion, and its efficiency was almost 10-times higher than that of the original Cd-MDIP.

Design and Construction of a Luminescent and Highly Stable 3D Metal–Organic Framework with a [Zn4(μ3-OH)2]6+Core

“…The K sv and detection limit values for Zn-MOF are comparable to those of the MOFs reported in the literature (see Table S5). For example, these values for {[Zn 3 (mtrb) 3 (BTC) 2 ]·3H 2 O} n and [Cd­(MDIP)­(H 2 O) 2 ] n are 1.78 μM and 6.50 × 10 3 M –1 and 80 nM and 4.13 x10 4 M –1 , respectively. − Thus, it can be anticipated from these results that Zn-MOF can be used as a potentially stable, fluorescent, and highly selective probe for the detection of Fe 3+ in water.…”

Thiol-Functionalized Zr Metal–Organic Frameworks for Efficient Removal of Fe ³⁺ From Water

“…Therefore, we conclude that the uncoordinated C=O and sulfur in UiO-66-S chelated the electron-poor Fe 3+ , leading to the remarkable adsorption capacity and rapid removal with high selectivity. [47][48][49] In addition, we performed density functional theory calculations to further study the Fe 3+ selectivity mechanism. We manually tested various adsorption sites and relaxed atoms to determine the most energetically favored structures (see the supplemental information for details).…”

A pH-stable Ag(i) multifunctional luminescent sensor for the efficient detection of organic solvents, organochlorine pesticides and heavy metal ions

“…There are reports in the literature where the detection of Fe 2+ , Hg 2+ , and Fe 3+ has been recorded in both organic and water media (Tables S7-S9 †). 10,30,[37][38][39][40][41][42][43][44][45][46][47][48][49] Compared with these examples reported, LCP 1 demonstrated impressive results.…”