Copper-(II) coordination compounds are prospective building blocks of magnetic materials for future technologies and biologically active compounds. Their magnetic properties are greatly influenced by coordinating ligands, counterions, cocrystallization partners, and crystal arrangements. The self-organization of crystal structures containing [Cu-(Arg)-(B)]2+ cationic complexes is largely determined by the type of counteranions. Using NO3 - ions resulted in the formation of a new copper-(II) l-arginato 1D polymeric complex, with the following formula: {[Cu-(l-Arg)-(phen)-(μ-NO3)]-(NO3)·H2O}n. The results demonstrate the importance of interactions between NO3 - and the [Cu-(l-Arg)-(phen)]2+ coordination units in constructing the unit cell, stabilizing the structure and the spectroscopic and magnetic properties. The [Cu-(l-Arg)-(phen)]2+ cations are linked by NO3 - axial-axial bridges with Cu···Cu distance of 7.071 Å, which induced weak antiferromagnetic interactions between copper-(II) ions with S = 1/2. The O···H intermolecular interactions mostly control the molecular packing. The EPR (g ⊥ = 2.056, g || = 2.230) and vis (16970 cm-1) parameters confirm the elongated octahedral geometry (T = 0.76) and SOMO oriented in the xy plane N3O coordination sphere. Solid-state 13C NMR spectroscopy is used to characterize the distribution of spin density in organic ligands, with relativistic two-component (SO-ZORA) DFT calculations used to interpret experimental 13C NMR data. Our current N3O coordination polymer belongs to an interesting class of weakly coupled antiferromagnetic compounds.

Three new triorganotin (IV) complexes 1, 2 (R = pH, n-Bu) and 3 (R = n-Bu) with functionalized heterocyclic azo and azo-imino carboxylate ligands viz.1-[(E)-2-(3-pyridyl)-1-diazenyl]-2‑hydroxy-3-naphthoic acid (H2L1) and 10-{(E)-4‑hydroxy-3-[(E)-iminomethyl]-2-(3-pyridyl)-phenyl-1-diazenyl}benzoic acid (H2L2) were synthesized and characterized using UV–Vis, FT-IR, multinuclear NMR (1H, 13C and 119Sn) spectroscopy techniques. The solid-state geometries of complexes 1 and 3 were determined by single-crystal X-ray crystallography. Complex 1 revealed a 1-D polymeric structure as a result of an intermolecular N→Sn bond between the N atom of the pyridyl ring and the Sn atom, resulting in a 5-coordinated distorted trigonal bipyramidal geometry around the tin atoms. Complex 3 exhibited a discrete cyclic dimeric structure also driven by the formation of an intermolecular N→Sn bond similar to complex 1, which resulting in a five-coordinate distorted trigonal bipyramidal geometry around the tin atom. The solution-state geometry of the triorganotin (IV) complexes was determined by NMR spectroscopic study. All three complexes adopted a 4-coordinated tetrahedral geometry around the tin atom. Hirshfeld surface analysis of 1 and 3 reveals that, in both complexes, the crystal packing is primarily determined by intermolecular contacts involving hydrogen atoms. DFT calculations and QTAIM analysis were also performed for 1 and 3. The antimicrobial activity of the ligands and complexes was evaluated against three bacterial species, viz. Bacillus subtilis, Micrococcus luteus, Escherichia coli and two fungal species viz. Fusarium oxysporum and Curvularia oryzae. All the complexes were found to be effective against the selected microbes, with varying antimicrobial activities, whereas the ligands showed low activity against only E. coli.

Copper(II) coordination compounds are prospective building blocks of magnetic materials for future technologies and biologically active compounds. Their magnetic properties are greatly influenced by coordinating ligands, counterions, cocrystallization partners, and crystal arrangements. The self-organization of crystal structures containing [Cu(Arg)(B)]2+ cationic complexes is largely determined by the type of counteranions. Using NO3 - ions resulted in the formation of a new copper(II) l-arginato 1D polymeric complex, with the following formula: {[Cu( l-Arg)(phen)(mu-NO3)](NO3)& centerdot;H2O}n. The results demonstrate the importance of interactions between NO3 - and the [Cu(l-Arg)(phen)]2+ coordination units in constructing the unit cell, stabilizing the structure and the spectroscopic and magnetic properties. The [Cu(l-Arg)(phen)]2+ cations are linked by NO3 - axial-axial bridges with Cu & centerdot;& centerdot;& centerdot;Cu distance of 7.071 & Aring;, which induced weak antiferromagnetic interactions between copper(II) ions with S = 1/2. The O & centerdot;& centerdot;& centerdot;H intermolecular interactions mostly control the molecular packing. The EPR (g perpendicular to = 2.056, g || = 2.230) and vis (16970 cm-1) parameters confirm the elongated octahedral geometry (T = 0.76) and SOMO oriented in the xy plane N3O coordination sphere. Solid-state 13C NMR spectroscopy is used to characterize the distribution of spin density in organic ligands, with relativistic two-component (SO-ZORA) DFT calculations used to interpret experimental 13C NMR data. Our current N3O coordination polymer belongs to an interesting class of weakly coupled antiferromagnetic compounds.

Two distinct crystal structures of a newly synthesized 1-methyl-5-(p-nitro-phenylazo)-6-aminouracil (LH3) and the previously known 1,3-dimethyl-5-(p-nitro-phenylazo)-6-aminouracil (LH2) were investigated. While LH3 has tetragonal symmetry with space group I41/a, LH2 has monoclinic symmetry with space group P21/c. Interestingly, unlike LH3, the projection of the azo-function relative to the 6-amino group of uracil in LH2 is entirely reversed. Both are E-conformer and planar and the plane of angle between the phenyl and the uracil rings reveals that LH2 (5.78(5)degrees) is more planar than LH3 (= 17.93(5)degrees). They are supposed to be formed distorted tetrahedral Ag(I) nitrate complexes, [AgI(LH3)(NO3)(H2O)] (1) with LH3 and [AgI(LH2)(NO3)(H2O)].4H2O (2) with LH2; the exact masses are 476.27 and 563.38, respectively, obtained from an ESI-mass spectrometry study. The complexes exhibit a strong stretching frequency of nu(NO3) at 1384 cm-1. The DFT structural optimizations of all the compounds were studied using the B3LYP method in DMSO solvent. The theoretically extracted bond parameters of the ligands are found in good agreement with their crystal structure values; for instance, the RMSD values for the azo-bond lengths are 0.0004 for the LH3 and 0.003 for the LH2. According to the DFT analysis, the ligands are preferably coordinated to Ag(I) through azo-N and uracil-O. The other two coordinating ligands are a water molecule and a nitrate ion. The Ag(I)-O(nitrate) bond lengths of 2.38385 & Aring; for 1 and 2.56253 & Aring; for 2, are comparable to values found in the literature. The coordination sites are supported by the molecular electrostatic potentials (MEP) and natural bond orbital (NBO) analysis. The NBO charges on the uracil-O and azo-N atoms increase from -0.574 and -0.199 to -0.653 and -0.256 in 1 and -0.593 and -0.144 to -0.636 and -0.202 in 2. In addition, due to the coordination environment the developed NBO charges on Ag-atom is 0.687 e for 1 and 0.737 e for 2.

This study describes the fabrication and examination of binuclear copper(II) phenylacetate (PAA) complex with metronidazole (mnz), formulated as [Cu2(μ‐PAA)4(mnz)2](mnz)2(H2O)2 (1). The complex was synthesized at room temperature and the product was characterized via FTIR, UV–Vis, and PXRD. The single‐crystal X‐ray diffraction of complex 1 reveals that it crystallizes in the triclinic space group P‐1. The SCXRD illustrated that complex 1 adopts a bidentate bridging mode with an almost ideal square‐pyramidal geometry (τ5 descriptor). Complex 1 is stabilized by extended hydrogen‐bonding networks, as confirmed by Hirshfeld surface analysis and 2D fingerprint plots. Quantitative analysis demonstrated that H···H interactions dominate the crystal packing (49.6% in 1), indicating that van der Waals forces are the major contributors to solid‐state stability. DFT calculations confirmed the structural stability and electronic features of the binuclear copper complex. FMO analysis revealed a narrow HOMO–LUMO energy gap (1.39 eV), indicating enhanced electronic responsiveness and chemical reactivity. RDG analysis indicated that molecular stability arises from a balance of coordination‐driven attractive interactions, weak dispersive forces, and localized steric effects. Furthermore, docking study against the SARS‐CoV‐2 main protease showed favorable binding affinity (−7.97 kcal/mol), suggesting potential biological relevance of the complex as a metal‐based bioactive scaffold.

Four triorganotin (IV) complexes 1-4 [R = Bu (1 and 3) and Ph (2 and 4)] were synthesized from two azo-carboxylate ligands, namely 4-[(E)-2-(4-methoxy/methylphenyl)-1-diazenyl]-3-hydroxy-2-naphthoic acid by reacting with bis-tri-n-butyltin (IV) oxide (compounds 1 and 3) triphenyltin (IV) chloride (compound 2) and triphenyltin (IV) hydroxide (compound 4). The complexes were characterized using UV, IR, and NMR (1H, 13C, and 119Sn) spectroscopy. The geometry around Sn atoms in the complexes in the solution state was determined by NMR spectroscopy. The study indicates that all the compounds adopt tetrahedral structure in solution. The mode of coordination and crystal structure of 2 in the solid state was established by X ray crystallography, revealing monomeric, five-coordinated deformation structure, intermediate between square pyramidal and trigonal bipyramidal geometries. The antidiabetic activities of the synthesized compounds were evaluated and compound 2 was found to be effective.

Novel reaction pathways with enhanced selectivity and yield for sustainable and green chemistry.

The salt formation of metronidazole (MET) and picric acid (PA) is obtained via slow evaporation of their mixture in methanol which afforded a novel organic salt, C6H10N3O3+& sdot;C6H2N3O7-(METPA). 6 H 10 N 3 O 3 + & sdot; C 6 H 2 N 3 O 7- (METPA). The structure of METPA salt was analyzed using single crystal X-ray diffraction. METPA crystallizes in the triclinic space group P-1 with cell dimensions: a = 8.2446(1), b = 9.1843(1), c = 11.5832(2) & Aring;, alpha = 106.190(1)degrees, degrees , beta = 99.483(1)degrees, degrees , gamma = 106.635(1)degrees, degrees , Volume (& Aring;3) 3 ) = 778.02(2) and Z = 2. The formation of METPA salt was analyzed by comparing the IR spectrum of MET, PA and METPA salt. In order to visualize the intermolecular interactions in the crystal of METPA salt, Hirshfeld surface analysis was employed. QTAIM calculations were performed using the AIMALL program package to estimate the strength of hydrogen bonding interactions in terms of bond critical points (BCP) and ring critical points (RCP). Molecular docking of the MET and METPA was conducted against three toxins of Clostridioides difficile such as C. difficile toxin A (TcdA), C. difficile toxin B (TcdB), C. difficile transferase (CDT). The results showed that the docking score calculated based on the knowledge-based iterative scoring function ITScore-PP indicates that METPA with higher negative value of docking score in case of all three toxins when compared to MET. This shows that the binding model of METPA salt is more favorable than MET.

In this paper, the application of organocatalysis in the synthesis of 2,3-dihydro-1H-pyrrolizines is demonstrated. α,β-Unsaturated aldehydes and pyrrole-based hydrazone readily participated in the formal (3+2)-cycloaddition that was realized according to aminocatalytic iminium ion activation. Products were obtained in high chemical yields, with excellent stereocontrol and selected additional transformations were also presented. The developed method was utilized in the first organocatalytic synthesis of ketorolac, a non-steroidal anti-inflammatory drug.

Two metal-organic co-crystal complexes with Mn(II) centre, [Mn(phen)2Cl2][4-hbaH] (1) and [Mn(phen)2(H2O) Cl]+[hip]- Cl- .H3O+.2H2O (2) where phen = 1,10-phenanthroline; 4-hbaH = 4-hydroxybenzoic acid; hip- = hippuric acid ion, were successfully synthesized by conventional reflux method and characterized using single crystal X-ray diffraction, spectroscopic, magnetic susceptibility, thermal and EDAX analysis data. SC-XRD analysis for 1 and 2 revealed the presence of distorted octahedral Mn(II) centre complex unit where the formation of metal-organic co-crystal complexes were confirmed from the dominant supramolecular non-covalent interactions such as halogen-bonding in 1 and hydrogen-bonding in 2. We explored the use of potential auxiliary ligands which embroidered through non-covalent interactions between organic and metal-organic moieties resulting in the formation of co-crystal with Mn(II) based supramolecular motif such as 4-hbaH in 1 and hip in 2. The complexes were screened for their activities and showed significant antibacterial properties against bacteria pathogens.

Two new mercury(II) chloride complexes with bidentate N,N-donor Schiff base ligands - (E)-2-((pyridin-2ylmethylene)amino)butan-1-ol (L1) and (E)-2-((pyridin-2-ylmethylene)amino)ethanol (L2) - have been synthesized via a one-pot reaction and characterized as [HgCl2(L1)]2 (1) and [HgCl2(L2)]n (2). Comprehensive characterization was performed using elemental analysis, molar conductance, FT-IR, UV-visible, 1H NMR, and fluorescence spectroscopy. Crystallizing in the triclinic space group P-1, complex 1 features a binuclear structure with each Hg(II) ion adopting a distorted square pyramidal geometry. Complex 2 crystallizes in the monoclinic space group I2/a as a one-dimensional polymeric chain, with each metal center exhibiting a distorted octahedral geometry. Hirshfeld surface analysis indicates significant noncovalent interactions __especially H & sdot;& sdot;& sdot;H, Cl & sdot;& sdot;& sdot;H, O & sdot;& sdot;& sdot;H, and C & sdot;& sdot;& sdot;H contacts - that contribute to crystal packing. The low molar conductance values in acetonitrile suggest their non-electrolytic nature. UV-visible and fluorescence studies support intramolecular charge transfer (ICT) transitions and weak metal-to-ligand charge transfer (MLCT) bands, attributed to transitions from Hg(II) to the pi* orbitals of the ligands.

Two dioxidovanadium(V) complexes, [VO2LH] (1) and [{VO2L}K(H2O)3] (2), containing a tridentate O, N, O donor Schiff base ligand salicylaldehyde-isonicotinoylhydrazone (H2L), have been synthesized. The synthesized ligand and corresponding complexes were structurally characterized by elemental analyses, FT-IR, UV-visible, and 1H NMR spectroscopy. Single crystal X-ray diffraction studies of the complexes (1, 2) show a distorted square pyramidal coordination environment around the metal centre. The synthesized dioxidovanadium(V) complexes were found to bind with CT-DNA in intercalative mode, with binding constant values for 1 and 2 calculated to be 1.16 x 104 M-1 and 1.08 x 104 M-1, respectively. The complexes show photocatalytic activity under visible light in the degradation of toxic cationic and anionic dyes, viz., methylene blue (MB) and rhodamine B (RhB), brilliant blue (BB), Congo red (CR), methyl orange (MO), and xylenol orange (XO) in aqueous medium.

The synthesis of uracil derivatives and their conversion to a number of potential compounds have drawn attention of researchers aiming to develop innovative materials. Therefore, a novel azo ligand, 1,3-dimethyl-5-(5 '-methyl-3 '-isoxazolyl-azo)-6-aminouracil (H2L, 1), was synthesized from 1,3-dimethyl-6-aminouracil and 3-amino-5-methyl-isoxazole. Compound 1 was converted to an 8-azaxanthine derivative, 1,3-dimethyl-8-(5 '-methyl-3 '-isoxazolyl)azaxanthine (2), via its reaction with Cu(NO3)26H2O in DMF solution. Alternatively, when 1 reacted with Cu(CH3COO)2H2O in the presence of NaN3 in methanol, an antiferromagnetic Cu(ii) complex (3) was formed, where Cu(ii) is found to be coordinated with the in situ-generated novel ligand 1,3-dimethyl-5-(but-2-one-3-ene-4-amino-azo)-6-aminouracil (L1) and azide ions. The structures of these compounds (1-3) were characterized using single crystal X-ray analysis. Complex 3 is a tetrameric assembly of Cu(ii) with a nearly parallelogram shape. Its Cu(ii) centers are interconnected through doubly end-on azide (mu 1,1-azide) bridges and doubly end-to-end azo (mu 1,2-azo) bridges. The theoretical study shows the presence of non-covalent interactions, including H-bonding and stacking interactions. Magnetic studies of 3, a nearly parallelogram tetranuclear Cu(ii) unit with side lengths of 3.7839(6) & Aring; and 4.7727(8) & Aring;, revealed that it possesses strong antiferromagnetic interactions, as evidenced by its exchange coupling constant J1 = -250 (1) cm-1 through end-on azide bridging between the Cu(ii) ions (Cu-N-Cu, 116 degrees). Thus, the present study not only introduces a strong antiferromagnetic material, but also establishes a notable correlation between its structure and magnetic properties.

In the manuscript, the application of temporary dearomatization of 2-benzyl-3-furaldehyde under aminocatalytic conditions in a 1,6-addition pathway is described. In such reaction setup catalytically generated dienamine derived from heteroaromatic aldehydes reacts with coumarin derivatives in 1,6-addition. Developed approach utilizes a catalytic system consisting of an aminocatalyst and an acidic cocatalyst, which is crucial for the reaction efficiency. The reaction displays a wide substrate scope generating target products containing furan and coumarin moieties.

A novel Cu(II) co-crystal compound, [Cu2(μ-acetate-κ1:κ1-O,O’)4(Isn)2][Cu(acetate-κ1-O)2(Isn)2(H2O)]⋅5H2O (1), (where Isn = isonicotinamide), was synthesized in ethanolic solution at room temperature. The compound was characterized by single-crystal X-ray diffraction, which revealed that it crystallizes in the monoclinic space group P2₁/c. The complex features two centrosymmetric paddle-wheel dicopper(II) moieties, a mononuclear unit, and five hydrogen-bonded water molecules. Both the lattice water molecules and the uncoordinated carboxylate oxygen atoms in the mononuclear moiety form a strong O–H⋯O hydrogen bonding network. Compound 1 represents a cocrystal structure formed by the incorporation of two chemically distinct copper complexes, one mononuclear and one dinuclear, into a single, ordered crystal lattice. Further analysis using FT − IR/FIR/Raman, NIR-Vis-UV spectroscopy, and computational methods, including Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) theory, was conducted to investigate intra- and intermolecular interactions. Two distinct complexes were identified in the unit cell: the mononuclear copper complex (M) and the dinuclear copper complex (D). Key intra-cell interactions were analyzed by examining two representative pairwise configurations: DD, consisting of two M units, and MD, formed by one M and one D unit. The interaction energies for DD and MD were − 27.3 kcal/mol and − 34.0 kcal/mol, respectively, after correcting for non-basis set superposition error (BSSE). The DD is stabilized by N–H···O hydrogen bonds, while the MD exhibits both π-π and hydrogen bond interactions, promoting enhanced stability and stacking along the b-axis. A frontier orbital gap of 2.6 eV suggests its potential for electronic, photonic, and sensing applications. Biological assays highlighted compound M’s significant antimicrobial activity, outperforming reference compounds like Cu(OAc)₂·H₂O and isonicotinamide against Candida albicans, MRSA, E. coli, and S. typhi. Molecular docking confirmed strong binding to C. albicans, with a binding energy of − 6.89 kcal/mol, whereas compound D showed moderate activity.

Divergent asymmetric NHC-catalyzed [8+n] higher-order cycloadditions using tropothione as an electron-poor 8π component were developed. The base-dependent selectivity of the synthetic approach allowed obtaining heterocyclic products bearing either γ- or δ-thiolactone rings with high enantioselectivity. The impact of base on NHC intermediate isomerization was explained by DFT studies. The diastereodivergency of the methodology was confirmed with both diastereomers being easy to isolate with very good results.

Five new zinc(II) azide complexes with the composition [Zn(N3)2(Ln)], where Ln = (E)-2,4-dimethoxy-N-((pyridin-2-yl)methylene)benzenamine, are reported herein. The complexes were characterized using UV-vis, fluorescence, IR, and 1H NMR spectroscopy, along with elemental analysis. The single-crystal structural analysis of compound 1 is presented. The mononuclear Zn(II) complex crystallized in the monoclinic system with the centrosymmetric space group P21/n. The asymmetric unit of complex 1 consists of two crystallographically independent molecules with quite similar geometries. The five-coordination geometry of the Zn(II) ions in 1 is irregular, best described as halfway between trigonal bipyramidal and square pyramidal geometries. Efforts to obtain single crystals of compounds 2-5 suitable for X-ray crystal structure analysis were unsuccessful. However, based on spectroscopic data and the structures of related zinc(II) complexes reported in the literature, complex 2 is proposed to have a geometry similar to that of complex 1, and complexes 3-5 are anticipated to have a four-coordinated tetrahedral geometry. All complexes were obtained in moderate-to-good yields and behave as non-electrolytes in acetonitrile solution. UV-vis and fluorescence spectral studies of complexes 1-5 indicate ligand-to-ligand (intra-ligand, pi-pi*) charge transfer transitions.

The first structurally characterized Cu(II) complex of sorbic acid (SA), compound 1 [Cup(mu -SA)a(MET)p], along with the Cu(II) complex of 3-phenylpropanoic acid (PPA), compound 2 [Cup(mu -PPA)a(METB)p], were synthesized and characterized. These complexes, supported by metronidazole (MET) and metronidazole benzoate (METB), were analyzed using FTIR, UV-vis spectroscopy, PXRD, thermal analysis, and single-crystal X-ray diffraction. Structural studies revealed dimeric arrangements with centrosymmetric syn-syn bidentate ligand coordination. Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analyses highlighted weak dispersion interactions, including CH & sdot;& sdot;& sdot;O, NOp & sdot;& sdot;& sdot;HC, C-H & sdot;& sdot;& sdot;pi, and pi & sdot;& sdot;& sdot;pi stacking, as well as tetrel-type stabilization. Molecular docking studies revealed that compound 2 exhibited the most favorable binding energy with Candida albicans receptors (4YDE and 3DRA), involving key interaction residues commonly found in active ligands. The magnetic properties of compounds 1 and 2 were thoroughly investigated, modeled, and analysed, yielding exchange coupling constants (J = -320 cm-1 for 1 and -330 cm-1 for 2), demonstrating strong antiferromagnetic interactions within the dicopper(II) tetrakis(mu -carboxylato)-bridged blocks.

We report herein the synthesis and characterization of [Mn2(POA)2(Phen)4](BF4)2 & sdot;H2O, 1 where POA = phenoxyacetate; Phen = 1,10-phenthroline, respectively. The crystalline complex was obtained via slow evaporation at room temperature and characterized by single crystal X-ray diffraction. FTIR and UV-vis spectroscopy were utilized to elucidate the structure of the new compound. Complex 1 crystallizes in the monoclinic crystal system with space group P 2 1 /n. Hirshfeld surface analysis revealed various intermolecular interactions in the crystal lattice. Quantum Theory of Atoms in Molecules (QTAIM), Reduced Density Gradient (RDG), and Natural Bond Orbital (NBO) analyses were employed to investigate the diverse non-covalent interactions stabilizing the crystal structure. In complex 1 , the BF 4- counterion plays a crucial role in crystal assembly through a network of F & sdot;& sdot;& sdot; H - C interactions with varying strengths governed by the interaction angle and consequent ellipticity. Additionally, B- F & sdot;& sdot;& sdot; pi interactions were observed. Other interactions include weak-to-medium hydrogen bonds and pi-interactions (CH & sdot;& sdot;& sdot;pi and pi & sdot;& sdot;& sdot;pi) within the asymmetric units and dimers extracted from the unit cell. Notably, unconventional interactions were identified and characterized in complex 1 , which is C- H & sdot;& sdot;& sdot; pi interactions with the sigma(CH) orbital donating to an empty p orbital in the asymmetric unit of 1 . Variable-temperature magnetic susceptibility data disclosed the occurrence of weak antiferromagnetic coupling within the doubly bridged manganese(II) core with a J value of - 2.11 cm- 1 .