Supramolecular clumps of µ2-1,3-acetate bridges of Cd(II)-Salen complex: Synthesis, spectroscopic characterization, crystal structure, DFT quantization's, and antifungal photodynamic therapy.

The article divulges the crystal growth, synthesis, and X-ray structure characterization of one centrosymmetric cadmium complex, [Cd{CdL(µ2-1,3-acetate)}2] using Salen ligand (SL). The complex is further characterized using spectroscopic and analytical techniques, including DRS, SEM-EDX, PXRD, and ICP-MS. The crystallographic study showed that the complex has a monoclinic space P21/c. Addison parameters (Æ®) show the hexagonal geometry of the central Cd(II) metal ion. Hirshfeld surface and 2-D fingerprint confirm supramolecular contacts despite weak C-H⋯O and C-H···π interactions. Energy frameworks, FMOs, global reactivity parameters, MEP, and energy bandgap explain the complex reactivity outlook. The complex inter- and intramolecular bonding interactions were explored through natural bond orbital (NBO), QTAIM, NCI-RDG, Electron Location Function (ELF), and Localized Orbital Locator (LOL) quantization methods. In addition, the complex and its synthetic components in vitro antibacterial efficacy were investigated using Gram-positive and Gram-negative microbial strains. SAR (structure-activity relationship) correlates with biological potency. Molecular docking assessed antimicrobial potency with proteins S. aureus (PDB ID: 1JIJ), C. albicans (PDB ID: 1M7A), E. coli (PDB ID: 1T9U), P. aeruginosa (PDB ID: 2UV0), and A. Niger (PDB ID: 3K4P). The findings are backed by the Protein-Ligand Interaction Profiler (PLIP). The antifungal potency and cell viability test of C. albicans were conducted using photodynamic therapy (APDT).

Synthesis, characterization, crystal structure, and fabrication of photosensitive Schottky device of a binuclear Cu(ii)-Salen complex: a DFT investigations.

This work explores one centrosymmetric binuclear Cu(ii)-Salen complex synthesis, characterization, photosensitive Schottky barrier diode (PSBD) function, and DFT spectrum. The crystal growth involves H2LSAL and Cu(NO3)2·3H2O in CH3OH + ACN (acetonitrile) solvent medium. Herein, structural characterization employs elemental, IR/Raman, NMR, UV-VIS, DRS, SEM-EDX, PXRD, SCXRD, and XPS analyses. The complex crystal size is 0.2 × 0.2 × 0.2, showing monoclinic space group C2/c. The dimeric unit contains two Cu(ii) centres with distorted square pyramidal (SQP) geometries. The crystal packing consists of weak C-H⋯O interactions. DFT and Hirshfeld surface (HS) further substantiated the packing interactions, providing valuable insights into the underlying mechanisms. The 2-D fingerprint plots showed the presence of N⋯H (3%) and O⋯H (8.2%) contacts in the molecular arrangement. NBO, QTAIM, ELF-LOL, and energy frameworks are utilized to investigate the bonding features of the complex. We extensively studied electrical conductivity and PSBD for H2LSAL and the complex based on band gap (3.09 and 3.07 eV). Like an SBD, the complex has better electrical conductivity, evidencing potentiality in optoelectronic device applications. Optical response enhances conductivity, according to I-V characteristics. Complex Schottky diode has lower barrier height, resistance, and higher conductivity under light. The complex transports charge carriers through space and is rationalized by the 'hopping process' and 'structure-activity-relationship' (SAR). The charge transport mechanism was analysed by estimating complex mobility (µeff), lifetime (τ), and diffusion length (LD). The experimental and theoretical DOS/PDOS plots provide evidence for the Schottky diode function of the complex.

Experimental and Theoretical Survey of Intramolecular Spodium Bonds/σ/π-Holes and Noncovalent Interactions in Trinuclear Zn(II)-Salen Type Complex with OCN- Ions: A Holistic View in Crystal Engineering.

In this work, one new centrosymmetric trinuclear Zn(II) complex 1, [{(OCN)Zn(L)}2Zn], using a salen-type ligand (H2L) in the presence of OCN- was synthesized and characterized via elemental, spectral, SEM-EDX, and single-crystal X-ray diffraction (SCXRD) study. In 1, SCXRD reveals two different stereochemical environments of zinc metal ions; one terminal Zn(II) center adopts square pyramidal geometries with the Addison parameter (τ) 0.095, and the central Zn(II) is tetracoordinated tetrahedral geometry. This article provides evidence of the significance and presence of spodium bonds (SpBs) in solid-state crystal structures involving a pseudotetrahedral environment of the central Zn-atom. X-ray structures reveal intramolecular Zn···O SpBs caused by the methoxy (-OCH3) substituent O-atom adjacent to the coordinated phenoxy O-atom. These noncovalent interactions have been thoroughly studied using density functional theory calculations at the RI-BP86[2]-D3[3]/def2-TZVP level of theory that characterizes the nature of SpBs, including the Baders quantum theory of atoms-in-molecules "QTAIM", molecular electrostatic potential (MEP) surface, and noncovalent index plot (NCI). In addition, a unique complex-isomer-based theoretical model has been vividly employed to estimate the SpBs energy in the complex. Natural bond orbital (NBO) analysis also tries to establish the differentiation between σ-hole and π-hole SpBs' natures more authentically. The complex energy frameworks were used to investigate noncovalent interactions. To better understand the different intermolecular interactions, we conducted a Hirshfeld surface, which revealed N···H (15.4%) and O···H (9.1%) contacts and Zn···O (5.1%) (SpBs).

Synthesis, spectroscopic investigation, molecular docking, ADME/T toxicity predictions, and DFT study of two trendy ortho vanillin-based scaffolds.

In this article, we have synthesized two contemporary ortho-vanillin-based Salen-type ligands (H2L1/H2L2) characterized by modern spectroscopic tools. EDX analysis supports the elemental composition (C, N, O, and Br). SEM examined the morphology of the synthesized compounds. The molecular geometry was optimized in the gas phase using B3LYP-D3/6-311G (d, p) level. The global reactivity parameters, HOMO-LUMO energy gap (Δ), atomic properties, MESP, and ADME/T, vividly explore the chemical reactivity and toxicity of two Salen-type ligands. The DFT simulated IR/NMR characterized essential structural assignments, and UV-Visible spectra were employed to predict the optical properties. The article demonstrated in silico molecular docking against the Gm + ve Bacillus subtilis (6UF6), and Gm -ve Proteus Vulgaris establishes the ligand binding ability with essential amino acids through conventional H-bonding or other significant interactions. The docking simulation is compared for two compounds better than the control drugs and confirms the antimicrobial activity. The theoretical drug-like properties have been explored in-depth by ADME/T using the SWISSADME database. The analysis estimated the molecule's lipophilicity, the consensus P0/W, and water solubility. Thus, using various pharmaco-logical parameters, toxicity explains where the electron-withdrawing Br group plays a more toxic effect in H2L2 than in H2L1.

Synthesis, spectroscopic findings, SEM/EDX, DFT, and single-crystal structure of Hg/Pb/Cu-SCN complexes: In silico ADME/T profiling and promising antibacterial activities.

This work contemplates synthesizing M-SCN crystal compounds (M = Hg/Pb/Cu) in the presence of respective metal salts and exogenous ancillary SCN- ion by slowly evaporating the mixed solvent (CH3OH + ACN). The complexes were characterized by spectroscopy, SEM/EDX, and X-ray crystallography. The Hg-Complex, Pb-Complex, and Cu-Complex crystallize in the monoclinic space group (Z = 2/4). The crystal packing fascinatingly consists of weak covalent bonding and Pb⋯S contacts of tetrel type bond. Here are the incredible supramolecular topographies delineated by the Hirshfeld surface and 2D fingerprint plot. The B3LYP/6-311++G (d, p) level calculations in the gas phase optimized the compound's geometry. The energy difference (Δ) between HOMO-LUMO and global reactivity parameters investigates the complex's energetic activity. MESP highlights the electrophilic/nucleophilic sites and H-bonding interactions. Molecular docking was conceded with the Gram- + ve bacterium Bacillus Subtilis (PDB ID: 6UF6) and the Gram-ve bacterium Proteus Vulgaris (PDB ID: 5HXW) to authenticate the bactericidal activity. ADME/T explains the various pharmacological properties. In addition, we studied the antibacterial activity with MIC (µg/mL) values and time-kill kinetics against Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6635) as Gram-positive, Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922) as Gram-negative bacteria.

The importance of tetrel bonding interactions with carbon in two arrestive iso-structural Cd(ii)-Salen coordination complexes: a comprehensive DFT overview in crystal engineering.

In this article, we describe the serendipitous synthesis of two remarkable iso-structural Cd(ii)-Salen complexes [L2Cd4(OAc)2(NCS)2] in the presence of H2L and NaSCN {where L = L1 (N,N'-bis(3-methoxysalicylidene)-1,2-diaminopropane) and L = L2 (N,N'-bis(3-methoxysalicylidene)-ethylenediamine) in 1 and 2, respectively}. The complexes were characterized by using elemental analysis, SEM-EDX, PXRD, spectroscopy, and X-ray crystallography. The X-ray crystal structure revealed that both complexes crystallize in the orthorhombic space group Pbcn, with unit cell parameters: a = 20.758(6), b = 11.022(3), c = 21.396(6) Å, V = 4895(2) Å3, and Z = 4. The inner N2O2 and outer O4 compartments are essentially occupied by two different Cd(ii) metal ions resulting from the de-protonated form of the ligand (L2-) with the Cd(1) metal ions adopting a capped octahedral geometry. At the same time, Cd(2) assumes a distorted trigonal prismatic geometry. The solid-state crystal structure involves various non-covalent supramolecular interactions delineated by Hirshfeld Surface and 2D fingerprint plot analysis. Noteworthily, interesting S⋯H, O⋯H, and N⋯H contacts were observed, which have identical percentages in both complexes. The sparse tetrel bonding interactions in the complex, involving the CH3 group, were evaluated in a new dimension of DFT. We observed this privileged bonding landscape that leads to the formation of self-assembled dimers in the crystal complexes. DFT-based MEP, RDG surface, NBO, and QTAIM/NCI plot investigation quantified such unique tetrel bonding interactions.

Synthesis, spectroscopic findings and crystal engineering of Pb(ii)-Salen coordination polymers, and supramolecular architectures engineered by σ-hole/spodium/tetrel bonds: a combined experimental and theoretical investigation.

Spontaneous self-assembly is one of the available synthetic routes to achieve structurally versatile and unique crystal complexes with selected metal-ligand combinations in the spirit of pseudohalides. In this endeavour, we designed a novel 1D coordination polymer (CP), [(Cd)(Pb)(L)(η1-NCS)(η1-SCN)] n (1), using a compartmental Salen ligand (H3L) in the presence of NaSCN. The characterization of the CP was accomplished using several spectroscopic techniques: MALDI-TOF, PXRD, SEM, EDX mapping, and single-crystal X-ray crystallography. The CP crystallizes in the monoclinic space group P21/c with Z = 4. SCXRD reveals Cd(ii) and Pb(ii) metal ions fulfilled distorted square pyramidal and hemi-directed coordination spheres. Cd(ii) is placed in the inner N2O2 and heavier Pb(ii) in the outer O4 compartments of the de-protonated form of the ligand [L]2-. Supramolecular interactions in the intricate crystal structure produced attractive molecular architectures of the compound. The flexible aliphatic -OH pendent group coordinates with the Pb(ii) ions. This unique binding further elevates the supramolecular crystal topographies. The supramolecular interactions were authenticated by Hirshfeld surface analysis (HSA). The observation of the recurring unconventional tetrel bonds was rationalized by DFT calculations and surface plots of molecular electrostatic potential (MEP). In the 1D polymeric chain in the complex, the O-atom of the -OH groups shows a tetrel bonding interaction with the Pb atom. We have found that the combination of QTAIM/NCI and QTAIM/ELF plots helps reveal the nature of these contacts. Moreover, the QTAIM/ELF plot determines the donor-acceptor interaction between the O-atom and the Pb atom, establishing the σ-hole. Agreeably, the σ-hole interaction also helps Pb(ii) serve as a Lewis acid in the complex. Finally, spodium and tetrel bonds are formed, possible thanks to a hemi-directional coordination sphere of the Pb atoms in the polymer described.

Dicyanamide-intertwined assembly of two new Zn complexes based on N2O4-type pro-ligand: Synthesis, crystal networks, spectroscopic insights, and selective nitroaromatic turn-off fluorescence sensing.

Two new dicyanamide bridged multinuclear Zn complexes, [Zn2(L1)(µ1,5-dca)2(µ1-dca)]n (1) and [Zn2(L2)(µ1,5-dca)2(µ1-dca)]n (2) have been synthesized using N2O4-based pro-ligands (H2L1 = N,N'-bis(5-bromo-3-methoxysalicylidenimino)-1,3-diaminopropane, H2L2 = N,N'-bis(3-ethoxysalicylidene)-2,2-dimethyl-1,3-propanediamine) and characterized by microanalytical and spectroscopic techniques. Both complexes are stable in solution and solid-state. Thermogravimetric analysis (TGA) findings showed that complexes are stable at room temperature. Single-crystal X-ray diffraction (SCXRD) has proven that complexes are identical structures where two zinc metal ions are crystallographically independent. The directional properties of dicyanamide co-ligands via µ1,5 bridging have resulted in different connectivity of zinc metal ions leading to 1D templates. SCXRD revealed some notable non-covalent interactions (π⋯π, C-H····π, and H-bonding) in their solid-state crystal structures. 1-2 have strong fluorescence behaviour over pro-ligands, which may be quenched in the presence of various electron-deficient explosive nitroaromatic compounds (epNACs). Complex 2 fluorescence intensity is sharper than 1; hence the former retained high sensitivity and selectivity for trinitrophenol (TNP). The enhancement of fluorescence mechanism, detection limit (LOD), and the quenching constant (KSV) have been calculated using the Stern-Volmer equation (SV), where the KSV value for TNP is found to be 1.542 × 104 M-1. The solution phase quenching mechanism has been rationalized by (a) electrostatic interactions through charge-transfer complex, (b) photo-induced electron transfer (PET) by the HOMO-LUMO energy gap via DFT, and (c) fluorescence resonance energy transfer (FRET). Finally, complex 2 is applied as a sensor by turn-off fluorescence response to detecting TNP nitroaromatics in the DMF medium.