Sequential Pore Functionalization in MOFs for Enhanced Carbon Dioxide Capture

The capture of carbon dioxide (CO2) is crucial for reducing greenhouse emissions and achieving net-zero emission goals. Metal-organic frameworks (MOFs) present a promising solution for carbon capture due to their structural adaptability, tunability, porosity, and pore modification. In this research, we explored the use of a copper (Cu(II))-based MOF called m CBMOF-1. After activation, m CBMOF-1 generates one-dimensional channels with square cross sections, featuring sets of four Cu(II) open metal sites spaced by 6.042 Å, allowing strong interactions with coordinating molecules. To investigate this capability, m CBMOF-1 was exposed to ammonia (NH3) gas, resulting in hysteretic NH3 isotherms indicative of strong interactions between Cu(II) and NH3. At 150 mbar and 298 K, the NH3-loaded (∼1 mmol/g) material exhibited a 106% increase in CO2 uptake compared to that of the pristine m CBMOF-1. Carbon-13 solid-state nuclear magnetic resonance spectra and density functional theory calculations confirmed that the sequential loading of NH3 followed by CO2 adsorption generated a copper-carbamic acid complex within the pores of m CBMOF-1. Our study highlights the effectiveness of sequential pore functionalization in MOFs as an attractive strategy for enhancing the interactions of MOFs with small molecules such as CO2.

A Review on Bioflocculant-Synthesized Copper Nanoparticles: Characterization and Application in Wastewater Treatment

Copper nanoparticles (CuNPs) are tiny materials with special features such as high electric conductivity, catalytic activity, antimicrobial activity, and optical activity. Published reports demonstrate their utilization in various fields, including biomedical, agricultural, environmental, wastewater treatment, and sensor fields. CuNPs can be produced utilizing traditional procedures; nevertheless, such procedures have restrictions like excessive consumption of energy, low production yields, and the utilization of detrimental substances. Thus, the adoption of environmentally approachable "green" approaches for copper nanoparticle synthesis is gaining popularity. These approaches involve employing plants, bacteria, and fungi. Nonetheless, there is a scarcity of data regarding the application of microbial bioflocculants in the synthesis of copper NPs. Therefore, this review emphasizes copper NP production using microbial flocculants, which offer economic benefits and are sustainable and harmless. The review also provides a characterization of the synthesized copper nanoparticles, employing numerous analytical tools to determine their compositional, morphological, and topographical features. It focuses on scientific advances from January 2015 to December 2023 and emphasizes the use of synthesized copper NPs in wastewater treatment.

Urea-rich porous organic polymer as a hydrogen bond catalyst for Knoevenagel condensation reaction and synthesis of 2,3-dihydroquinazolin-4(1H)-ones

In this research, a new urea-rich porous organic polymer (urea-rich POP) as a hydrogen bond catalyst was synthesized via a solvothermal method. The physiochemical properties of the synthesized urea-rich POP were investigated by using different analyses like Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), energy-dispersive X-ray spectroscopy (EDS), elemental mapping analysis, X-ray diffraction analysis (XRD) and Brunauer-Emmett-Teller (BET) techniques. The preparation of urea-rich POP provides an efficacious platform for designing unique hydrogen bond catalytic systems. Accordingly, urea-rich POP, due to the existence of several urea moieties as hydrogen bond sites, has excellent performance as a catalyst for the Knoevenagel condensation reaction and multi-component synthesis of 2,3-dihydroquinazolin-4(1H)-ones.

Constructing a metal-free 2D covalent organic framework for visible-light-driven photocatalytic reduction of CO2: a sustainable strategy for atmospheric CO2 utilization

A 2D polyimide-linked covalent organic framework (COF) with band gap energy of 2.2 eV is developed as a stable and efficient porous photocatalyst which shows CO2 reduction to formic acid, formaldehyde and methanol.

Novel Cyclic Peptides for Targeting EGFR and EGRvIII Mutation for Drug Delivery

The epidermal growth factor-epidermal growth factor receptor (EGF-EGFR) pathway has become the main focus of selective chemotherapeutic intervention. As a result, two classes of EGFR inhibitors have been clinically approved, namely monoclonal antibodies and small molecule kinase inhibitors. Despite an initial good response rate to these drugs, most patients develop drug resistance. Therefore, new treatment approaches are needed. In this work, we aimed to find a new EGFR-specific, short cyclic peptide, which could be used for targeted drug delivery. Phage display peptide technology and biopanning were applied to three EGFR expressing cells, including cells expressing the EGFRvIII mutation. DNA from the internalized phage was extracted and the peptide inserts were sequenced using next-generation sequencing (NGS). Eleven peptides were selected for further investigation using binding, internalization, and competition assays, and the results were confirmed by confocal microscopy and peptide docking. Among these eleven peptides, seven showed specific and selective binding and internalization into EGFR positive (EGFR+ve) cells, with two of them-P6 and P9-also demonstrating high specificity for non-small cell lung cancer (NSCLC) and glioblastoma cells, respectively. These peptides were chemically conjugated to camptothecin (CPT). The conjugates were more cytotoxic to EGFR+ve cells than free CPT. Our results describe a novel cyclic peptide, which can be used for targeted drug delivery to cells overexpressing the EGFR and EGFRvIII mutation.

Organogel-assisted porous organic polymer embedding Cu NPs for selectivity control in the semi hydrogenation of alkynes

Heteroatom-rich porous-organic-polymers (POPs) comprising highly cross-linked robust skeletons with high physical and thermal stability, high surface area, and tunable pore size distribution have garnered significant research interest owing to their versatile functionalities in a wide range of applications. Here, we report a newly developed organogel-assisted porous-organic-polymer (POP) supported Cu catalyst (Cu@TpRb-POP). The organogel was synthesized via a temperature induced gelation strategy, employing Schiff-base coupling between 2,4,6-triformylphloroglucinol aldehyde (Tp) and pararosaniline base (Rb). The gel is subsequently transformed to hierarchical porous organic structures without the use of any additive, thereby offering advantageous features including extremely low density, high surface area, a highly cross-linked framework, and a heteroatom-enriched backbone of the polymer. During the semi-hydrogenation of terminal and internal alkynes, the Cu@TpRb-POP-B catalyst with Cu embedded in the TpRb-POP structure consistently demonstrated improved selectivity towards alkenes compared to Cu@TpRb-POP-A, which contains Cu NPs exposed at the exterior surfaces of the POP support. Additionally, Cu@TpRb-POP-B showed higher stability and reusability than Cu@TpRb-POP-A. The superior performance of the Cu@TpRb-POP-B catalyst is attributed to the steric hindrance effect, which controls the product selectivity, as well as the synergistic interaction between the heteroatom-rich POP framework and the embedded Cu NPs. Both the effects are corroborated by experimental characterization of the catalysts and density functional theory (DFT) calculations.

Zn(II)-Functionalized COF as a Recyclable Catalyst for the Sustainable Synthesis of Cyclic Carbonates and Cyclic Carbamates from Atmospheric CO2

A simple covalent organic framework (COF) bearing β-ketoenamine units as a potential heterogeneous ligand for ZnII-catalyzed fixation and transformation of CO2 into value-added chemicals is reported. Catalytic investigations convincingly demonstrated...

Indium(III)-Catalyzed Synthesis of Primary Carbamates and N-Substituted Ureas

An indium triflate-catalyzed synthesis of primary carbamates from alcohols and urea as an ecofriendly carbonyl source has been developed. Various linear, branched, and cyclic alcohols were converted into the corresponding carbamates in good to excellent yields. This method also provided access to N-substituted ureas by carbamoylation of amines. All the products were obtained by simple filtration or crystallization, without the need for chromatographic purification. Mechanistic investigations suggest that the carbamoylation reaction proceeds through activation of urea by O-coordination with indium, followed by nucleophilic attack by the alcohol or amine on the carbonyl center of urea. The inexpensive and easily available starting materials and catalyst, the short reaction times, and the ease of product isolation highlight the inherent practicality of the developed method.