Possibility of Complexation of the Calix[4]Arene Molecule with the Polluting Gases: DFT and NCI-RDG Theory

The calix[4]arenes (abbreviated as CX[4]) are characterized by a specific hydrophobic cavity formed by a four cyclically phenol groups to encapsulate a gas or small molecules. Recently, the CX[4] molecule is used in a specific media and in pharmaceutical drug delivery. The pollution problem will be a vital subject in the future because the increase of the explosions of the gaseous pollutants in the environment. In this report, we have encapsulated the polluting gases NO3, NO2, CO2 and N2 by the calix[4]arene molecule. In this work, The binding energies of the CX[4]-gas has been calculated including the BSSE (Basis Set Superposition Error) counterpoise (CP). The red-shift of the O-H bonding interactions obtained by adding the gas in the sensitive area of calix[4]arene is clearly explained by the infrared spectrum analysis. The Molecular electrostatic potential (MEP) of the stable CX[4]-gas complexes have been investigated in the endo-vs. exo-cavity regions. Finally, the non-covalent interactions analyses of the stable host-guests complexes have been estimated by using DFT calculations

Preparation, Characterizations and Theoretical Calculations of a Mg(II) Porphyrin Complex with Axial O-bonded 4-Pyrrolidinopyridine

International audienceWe hereby report the synthesis of a new hexacoordinated magnesium(II) metalloporphyrin with the formula [Mg(TBrPP)(4-pypo-κO)2] (1) where TBrPP is the meso-tetra(para-bromophenyl)porphyrinate and (4-pypo-κO) is the O-bonded 4-pyrrolidinopyridine axial ligand. This Mg(II) coordination is considered the linking isomer of the already known N-bonded 4-pyrrolidinopyridine (4-pypo-κN) with the formula [Mg(TTP)(4-pypo-κN)2] where TTP is the meso-tetra(p-tolyl)porphyrinate. Complex 1 was characterized by elemental analysis, IR, 1H NMR, UV/Vis and fluorescence spectrometric techniques, cyclic voltammetry measurements as well as single-crystal X-ray diffraction analysis. The Wingx supported program PLATON and the Hirshfeld surface analysis were both used to elucidate the intermolecular interactions in the crystal lattice of complex 1. Computational studies at DFI/B3LYP-D3/6-31G(d,p)-LanL2DZ level of DFT were used to elucidate the minimum energy geometry, the HOMO and LUMO molecular orbitals characteristics and the reactivity of complex 1. The molecular electrostatic potential (MEP) calculations on complex 1 have been made to determine the electrophilic-nucleophilic character of our new Mg(II) metalloporphyrin. Furthermore, the quantum theory atom in molecule (QTAIM) calculations were performed to get more insights into the type of interactions between the [Mg(TBrPP)] moiety and the two 4-pyrrolidinopyridine axial ligands of complex 1. © 2023 Elsevier B.V

A theoretical and electrochemical impedance spectroscopy study of the adsorption and sensing of selected metal ions by 4-morpholino-7-nitrobenzofuran

The selectivity of a novel chemosensor, based on a modified nitrobenzofurazan referred to as NBD-Morph, has been investigated for the detection of heavy metal cations (Co2+, Pb2+, Mg2+, Ag+, Cu2+, Hg2+, Ni2+, and Zn2+). The ligand, 4-morpholino-7-nitrobenzofurazan (NBD-Morph), was characterized using spectroscopic techniques including FT-IR and 1H NMR. Vibrational frequencies obtained from FT-IR and proton NMR (1H) chemical shifts were accurately predicted employing the density functional theory (DFT) at the B3LYP level of theory. Furthermore, an examination of the structural, electronic, and quantum chemical properties was conducted and discussed. DFT calculations were employed to explore the complex formation ability of the NBD-Morph ligand with Co2+, Pb2+, Mg2+, Ag+, Cu2+, Hg2+, Ni2+, and Zn2+ metal cations. The comparison of adsorption energies for all possible conformations reveals that NBD-Morph exhibits sensitivity and selectivity towards metal ions, including Pb2+, Cu2+, Ag+, and Ni2+. However, an assessment of their reactivity using QTAIM topological parameters demonstrated the ligand's greater complexation ability toward Cu2+ or Ni2+ than those formed by Pb2+ or Ag+. Additionally, molecular electrostatic potential (MEP), Hirshfeld surfaces, and their associated 2D-fingerprint plots were applied to a detailed study of the inter-molecular interactions in NBD-Morph-X (X = Pb2+, Cu2+, Ag+, Ni2+) complexes. The electron localization function (ELF) and the localized-orbital locator (LOL) were generated to investigate the charge transfer and donor-acceptor interactions within the complexes. Electrochemical analysis further corroborates the theoretical findings, supporting the prediction of NBD-Morph's sensory ability towards Ni2+ metal cations. In conclusion, NBD-Morph stands out as a promising sensor for Ni2+