Investigations based on non-covalent interactions in 1-(4-chloromethylbenzoyl)-3-(4, 6-di-substituted pyrimidine-2-yl)thioureas: Synthesis, characterizations and quantum chemical calculations

Exploration of intramolecular charge transfer in para-substituted nitrobenzofurazan: Experimental and theoretical analyses

The present work aims at exploring the high electrophilic character of 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) toward the morpholine group by an S_NAr reaction in acetonitrile or water (thereafter referred to as NBD-Morph). The electron-donating ability of the morpholine causes intra-molecular charge transfer (ICT). In this report, we present a comprehensive study on the optical characteristics using UV-Vis, photoluminescence (cw-PL) and its time-resolved (TR-PL) to determine the properties of the emissive intramolecular charge transfer (ICT) in the NBD-Morph donor-acceptor system. An exhaustive theoretical investigation utilizing the density functional theory (DFT) and its extension TD-DFT methods is an essential complement of experiments to rationalize and understand the molecular structure and related properties. The findings from QTAIM, ELF, and RDG analyses establish that the bonding between morpholine and NBD moieties is of the electrostatic or hydrogen bond type. In addition, the Hirshfeld surfaces have been established to explore the types of interactions. Further, the non-linear optical (NLO) responses of the compound have been examined. The structure-property relationships obtained through the combined experimental and theoretical offer valuable insights for designing efficient NLO material.

Synthesis, Structure, Hirshfeld Surface Analysis, Non-Covalent Interaction, and In Silico Studies of 4-Hydroxy-1-[(4-Nitrophenyl)Sulfonyl]Pyrrolidine-2-Carboxyllic Acid

The new compound 4-hydroxy-1-[(4-nitrophenyl)sulfonyl]pyrrolidine-2-carboxyllic acid was obtained by the reaction of 4-hydroxyproline with 4-nitrobenzenesulfonyl chloride. The compound was characterized using single crystal X-ray diffraction studies. Spectroscopic methods including NMR, FTIR, ES-MS, and UV were employed for further structural analysis of the synthesized compound. The title compound was found to have crystallized in an orthorhombic crystal system with space group P212121. The S1-N1 bond length of 1.628 (2) Å was a strong indication of the formation of the title compound. The absence of characteristic downfield 1H NMR peak of pyrrolidine ring and the presence of S-N stretching vibration at 857.82 cm-1 on the FTIR are strong indications for the formation of the sulfonamide. The experimental study was complemented with computations at the B3LYP/6-311G +  + (d,p) level of theory to gain more understanding of interactions in the compound at the molecular level. Noncovalent interaction, Hirsfeld surface analysis and interaction energy calculations were employed in the analysis of the supramolecular architecture of the compound. Predicted ADMET parameters, awarded suitable bioavailability credentials, while the molecular docking study indicated that the compound enchants promising inhibition prospects against dihydropteroate synthase, DNA topoisomerase, and SARS-CoV-2 spike.

Graphical Abstract

Herein we present the solid state structure, noncovalent interaction and spectroscopic analysis of a prospective bioactive compound 4-hydroxy-1-[(4-nitrophenyl)sulphonyl]pyrrolidine-2-carboxyllic acid.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10870-023-00978-0.

Functional group modified 1D interpenetrated metal-organic frameworks on perfluorooctanoic acid adsorption: Experimental and theoretical calculation study

Functional groups modified metal-organic frameworks (MOFs) was synthesized via a pre-tailor method and served as an adsorbent for perfluorooctanoic acid (PFOA) removal. The material was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and N₂ sorption-desorption. Monte Carlo simulation and molecular dynamics are derived to predict the possible molecular packing and adsorption mechanism. The Hirshfeld surface with reduced density gradient analysis demonstrates that PFOA is adsorbed on MOF-X mainly affected by van der Waals interactions and steric effects. Adsorption kinetics and isotherms were investigated on the basis of a static experiment. The pseudo-second-order kinetic model and Langmuir isotherm were fitted well to characterize adsorption process. Hereinto, amino-modified MOFs reached the highest adsorption efficiency and the maximum capacity was 185.6 mg/g. Combing the experimental data with theoretical simulation, results indicated that functional group modification is an effective approach to alter the crystal structure and then affect the adsorptive properties of MOFs.

A Dual Approach on Experimental, Theoretical Insight of Structural Elucidation, Hirshfeld Surface Analysis, Optical and Electrochemical Properties of Acyl Thiourea-Ethynyl Hybrid Derivatives

Hybrid moieties of ethynylated-thiourea, Th1 and Th2 have been synthesised via the addition reaction between ethynyl derivatives and 4-tert-butylbenzoyl isothiocyanate in acetone, and were characterised by selected spectroscopic methods (i.e., ¹H and ¹³C NMR, UV-visible, FT-IR) and elemental analysis. Thermogravimetric analysis indicated that Th1 and Th2 were relatively stable up to ca. 210 °C. Single-crystal X-ray diffraction was used to identify the crystal structure of Th2 in which the centre of 1-acyl thiourea moiety (-C(O)NHC(S)NH) exhibits S conformation. The Hirshfeld surface analysis has allowed visualizing the crystal packing, which is characterised by the prolonged intermolecular N-H⋯O = C and N-H⋯S = C hydrogen-bonding interactions within Th2 molecule. Electrochemical data of both compounds correspondingly exhibit irreversible redox potential processes. Besides, frontier molecular orbitals and Natural Bond Orbital population analysis were computed at the B3LYP/6-31G (d, p) level of approximation, suggesting strong delocalization of the electronic density through a conjugated π-system involving the ethynyl-phenyl and thiourea groups.

GRAPHICAL ABSTRACT

Figure of molecular structure for acyl thiourea-ethynyl derivative. Two derivatives of acyl thiourea-ethynyl were synthesised and characterised by selected spectroscopic methods such as 1H and 13C NMR, UV-visible, FT-IR, elemental, thermal, electrochemical, X-ray diffraction, and density functional theory (DFT) calculation for molecular orbitals and natural bond orbital population analysis.