A novel 3D Zn-coordination polymer based on a multiresponsive fluorescent sensor demonstrating outstanding sensitivities and selectivities for the efficient detection of multiple analytes

Design and preparation of a multi-responsive Cd-based fluorescent coordination polymer for smart sensing of nitrobenzene and ornidazole

The improper utilization of nitrobenzene (NB) and ornidazole (ORN) has resulted in irreversible effects on the environment. By combining experimental investigation, density functional theory (DFT) calculations, and machine learning, an effective green strategy for detecting NB and ORN in aqueous solutions can be developed. In this study, a one-dimensional Cd-based coordination polymer (Cd-HCIA-3) was designed and synthesized using 5-((4-carboxybenzyl)oxy)isophthalic acid and rigid 2,2'-bipyridine under solvothermal reaction conditions. Cd-HCIA-3 exhibits excellent fluorescence properties and stability in aqueous solutions. DFT calculations were performed to predict the fluorescence sensing performance of Cd-HCIA-3, revealing that photoinduced electron transfer is the key mechanism for inducing fluorescence quenching in the presence of NB and ORN, with weak molecular interactions promoting electron transfer. Fluorescence sensing experiments were conducted to verify the DFT results, showing that Cd-HCIA-3 can selectively detect NB and ORN in aqueous solutions with limits of detection of 7.22 × 10-8 and 1.31 × 10-7 mol/L, respectively. This study's findings provide valuable insights into the design and synthesis of fluorescent coordination polymers for target analytes.

A Zn-coordination polymer for the quantitative and selective colorimetric detection of residual tetracycline in aqueous solution and urine

A one-step solvothermal synthesis provides a functional crystalline one-dimensional Zn-coordination polymer (Zn-CP) with excellent stability in aqueous solution over a wide range of temperature and pH. Zn-CP is a rapid, highly sensitive and selective sensor for detecting tetracycline (TC). Quantitative TC detection is based on the ratio of fluorescence intensities I₅₃₀/I₄₂₀, with a limit of detection (LOD) of 5.51 nM in aqueous solution and 47.17 nM in human urine. The characteristics of colorimetric TC sensing by Zn-CP are highly favorable for application because the color of Zn-CP changes in the visible part of the spectrum from blue-purple to yellow-green upon addition of TC. Conversion of these colors into an RGB signal is simply achieved with an app for the smart phone and provides LODs of 8.04 nM and 0.13 μM TC in water and urine, respectively. Our suggested sensing mechanisms assume that the fluorescence intensity of Zn-CP@TC at 530 nm is enhanced by energy transfer of Zn-CP to TC, while the fluorescence of Zn-CP at 420 nm is quenched by photoinduced electron transfer (PET) from TC to the organic ligand in Zn-CP. These fluorescence properties make Zn-CP a convenient, low-cost, rapid and green detection device for monitoring TC under physiological conditions and in aqueous media.

Stimuli-Responsive Zinc (II) Coordination Polymers: A Novel Platform for Supramolecular Chromic Smart Tools

The unique role of the zinc (II) cation prompted us to cut a cross-section of the large and complex topic of the stimuli-responsive coordination polymers (CPs). Due to its flexible coordination environment and geometries, easiness of coordination-decoordination equilibria, "optically innocent" ability to "clip" the ligands in emissive architectures, non-toxicity and sustainability, the zinc (II) cation is a good candidate for building supramolecular smart tools. The review summarizes the recent achievements of zinc-based CPs as stimuli-responsive materials able to provide a chromic response. An overview of the past five years has been organised, encompassing 1, 2 and 3D responsive zinc-based CPs; specifically zinc-based metallorganic frameworks and zinc-based nanosized polymeric probes. The most relevant examples were collected following a consequential and progressive approach, referring to the structure-responsiveness relationship, the sensing mechanisms, the analytes and/or parameters detected. Finally, applications of highly bioengineered Zn-CPs for advanced imaging technique have been discussed.