Although the detection of biomarkers epinephrine (EP) and homovanillic acid (HO) is critical for early diagnosis and personalized medicine, the development of a luminescent sensor for their precise quantification remains an ongoing challenge. In this work, a unique porous Hf6-based metal–organic framework (MOF), [Hf6(μ3-O)4(μ3-OH)4(OH)4(H2O)4(PPTA)2]·xS (denoted as 1), with high acid stability was synthesized. It serves as a dual-function luminescence sensor for EP and HO detection, achieving low limits of detection of 9.3 × 10–9 and 1.8 × 10–7 mol/L, respectively. Besides, the thin film 1@CRG can be simply synthesized for visual detection of EP and HO, demonstrating great potential for home-testing use. This work presents a new MOF-based sensing platform, paving the way for advanced multianalyte biomarker detection in clinical diagnostics.
In this comprehensive investigation, we present an integrated computational and experimental study of a series of metal-doped supramolecular PDI(β-ala)-GMP complexes using Ag(I)/Co(II)/Zn(II) as central metal ions. The supramolecular assemblies were critically analyzed in terms of optoelectronic properties and electronic behaviors. High-order computational studies, such as noncovalent interaction (NCI) and reduced density gradient (RDG) isosurface mapping, electron density difference maps (EDDM), Hirschfeld surface analysis, and frontier molecular orbital (FMO) theory, gave a more in-depth insight into the electronic structure, charge transfer, and the intermolecular interactions. Additionally, stability indices, natural bond order (NBO) analysis, dipole moment measurements, and full optoelectronic property calculations were done to rationalize structure–property relationships. The formation and stability of the metal-doped supramolecular architectures were experimentally validated by the use of spectroscopic (ultraviolet–visible (UV–vis), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR)) and structural (PXRD) methods. It is important to note that Zn2PDI(GMP)2(H2O)4 complex exhibited a better electronic delocalization and strong intermolecular interactions, thereby making it one of the most promising products in the next-generation photonic and optoelectronic applications. This work provides the design principles of engineering supramolecular materials with the desired optoelectronic properties that lie between computational predictions and experimental assembly.
Utilizing CO2 for the synthesis of value-added chemicals offers an economically viable route while contributing to reducing greenhouse gas emissions. In this study, three ligands with N2O2 binding sites were designed and used to synthesize mononuclear three cobalt(III) complexes, 1–3, for catalytic activity in the N-formylation reaction. A comparative study was conducted using DMAB as a greener hydrogen donor compared to triethylsilane in the presence of CO2 as a C1 source. All complexes were characterized by UV–Vis, FT-IR, and single-crystal X-ray analysis. Although complex 2 showed the highest activity, all three homogeneous complexes displayed comparable efficiency and were thus employed to develop magnetically separable nanocatalysts for improved recoverability and reusability. Immobilizing the Schiff base complexes onto graphene oxide, Fe3O4, and APTES yielded three magnetically separable GO@Fe3O4@APTES@CoL1/2/3 nanocatalysts. The heterogeneous catalyst obtained from complex 2, i.e., GO@Fe3O4@APTES@CoL2 (GOFeTESCoL2), was catalytically more efficient than the other two. This new heterogeneous magnetically separable nanocatalyst, GOFeTESCoL2, was then characterized by FT-IR, scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, BET analysis, and X-ray photoelectron spectroscopy, which confirmed successful surface modification. GOFeTESCoL2 is magnetically separable and can be reused for six cycles without any loss of catalytic activity or product yield. This reusability offers a cost-effective nonprecious metal-based catalytic approach that minimizes potential reaction losses.
Biaryl motifs are central in pharmaceutical drug design, yet conventional synthesis via palladium-catalyzed cross-coupling poses increasing sustainability and cost concerns. The study presented herein explores a greener alternative to palladium using iron(II) complexes supported by tetra-aza macrocyclic ligands for direct arylation of pyrrole with phenylboronic acids. Under aerobic conditions, the optimized [Fe2+L1(Cl)2] complex of ligand Me2Cyclam (L1; 1,8-dimethyl-1,4,8,11-tetraazacyclotetradecane) showed broad substrate compatibility across 23 derivatives, achieving yields up to 66%, and excellent tolerance for functional groups including halides, esters, and strong electron-deficient substituents. Systematic analysis of these results suggests that meta-substitution and mild electron-withdrawing effects favor reactivity, while bulky ortho-steric hindrance suppresses coupling. Mechanistic studies ruled out outer-sphere radical pathways and high-valent iron complexes but do suggest iron(III)-hydroperoxo species as the operative oxidant. Density functional theory (DFT) analysis was carried out on the boronic acid substrates to show that electron-withdrawing substituents enhance the boron electrophilicity and promote the proposed transmetalation step, positioning this step as a key target for mechanistic activation of the substrate. These findings highlight the potential of earth-abundant iron catalysts as sustainable, cost-effective platforms for C–C bond formation in complex molecular scaffolds.
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