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Two mono‐ and dinuclear Bi(III) complexes, [Bi(L)2(NO3)2]·NO3 (1) and [Bi2(L)2Cl8] (2) (L = (2‐(2‐pyridyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide), were obtained via complexation of L with Bi(III) nitrate pentahydrate and Bi(III) chloride. L and both complexes were characterized by elemental analyses and spectroscopic methods including FT‐IR, UV–Vis, and fluorescence spectroscopy. Specifically, it clearly manifested that both complexes had good fluorescence emission and showed different fluorescence behaviors in diverse solvents. Both Bi(III) complexes were further determined by X‐ray crystallography, and it was found that the ratio of ligand to metal was 2:1 in 1, whereas 2 was 1:1. Their coordination geometric configurations were significantly different, such as octa‐coordinated complex 1 formed an infinite 1‐D chain‐like, funnel‐shaped 2‐D network, and ladder‐like 3‐D supramolecular framework, whereas hexa‐coordinated complex 2 with a binuclear structure exhibited two slightly distorted octahedral geometric structures; meanwhile, symmetric units came into being an infinite 2‐D layer even and meter‐shaped 3‐D supramolecular skeleton. The optimal geometries, frontier molecular orbital energies, and molecular electrostatic potential diagrams of both complexes were calculated using DFT/B3LYP. The electronic distribution of HOMO‐LUMO rationalized the results of UV–Vis spectra with the help of TD‐DFT calculations. Furthermore, all samples demonstrated excellent antibacterial activities against Escherichia coli and Staphylococcus aureus. In addition, non‐covalent interactions of complexes and their contributions were quantified with Hirshfeld surfaces using CrystalExplorer17 program. [ABSTRACT FROM AUTHOR]

Two mononuclear and dinuclear octahedral complexes, [Mn(L1)2Cl2] (1) and [Bi2(L2)2Cl8] (2) (L1 = 2‐(2‐pyridyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide, L2 = 2‐(3‐pyridyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide) were prepared by natural volatilization method. The ligands and both complexes were compared with spectroscopic methods, as well as characterized by elemental analysis. The photoluminescence behaviors of both complexes in different solvents were also investigated. The coordination possibility of ligands toward Mn (II)/Bi (III) was verified using X‐ray crystallography, and it revealed that the ratio of ligand to metal was 2:1 in 1, whereas 1:1 in 2. The adjacent molecules of six‐coordinated complex 1 constituted an infinite 1‐D chain, 2‐D network, and ladder‐like 3‐D supramolecular frameworks. Most strikingly, hexa‐coordinated complex 2 with dinuclear structure formed an infinite 1‐D chain, 2‐D layered and meter‐shaped 3‐D supramolecular skeleton. Density functional theory (DFT) calculation was used to optimize the geometry of complexes, compute the electrostatic potential diagrams, and evaluate the HOMO‐LUMO energy gap. The electronic transition simulated through time‐dependent (TD)‐DFT level of calculation rationalized the experimental data. The antibacterial properties of all compounds were evaluated against Gram‐positive and Gram‐negative bacterial strains. In addition, the Hirshfeld surface was utilized to quantify some hydrogen bonding interactions and their contributions. [ABSTRACT FROM AUTHOR]

Two complexes [Cd(L)2(NO3)2] (1) and [Ni(L)2(OH)2][Ni(L)2(CH3OH)2](NO3)2·CH3OH (2) (L = 2‐[2‐pyridyl]‐4‐methyl‐1,2‐dihydroquinazolin 3‐oxide) were gained via complexation an amount of the new ligand L with different nitrate salts. The obtained complexes were characterized by elemental analysis, spectroscopy, and X‐ray crystallographic. In the crystal structure, centrosymmetric 1 adopted slightly distorted octahedral geometry. On the other hand, the independent unit of 2 contained two half Ni (II) complex located on a center of symmetry, differing for the axial ligand, two uncoordinated nitrate ions, and one lattice methanol molecule. Both the crystal structures formed a 3‐D supramolecular architecture through different interactions (H‐bonds, π···π, etc). X‐ray crystallography revealed that complexes 1 and 2 had 2:1 ligand‐to‐metal ratios. Most strikingly, 1 performed different fluorescence behaviors in diverse solvents, whereas 2 exhibited fluorescence quenching. When 1 was dissolution in N,N‐dimethylformamide (DMF) solvent system, it has better fluorescence properties. The geometry optimization and HOMOs and LUMOs energies of both complexes were calculated by density functional theory (DFT) methods, and the nucleophilic and electrophilic attack sites were confirmed with electrostatic potential (ESP) calculations. Preliminary investigation of antimicrobial activities of all compounds against Gram‐negative bacteria (Escherichia coli) and Gram‐positive bacteria (Bacillus subtilis) was reported. Additionally, CrystalExplorer program was used to quantify the noncovalent interactions in complexes 1 and 2 through Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

The quinazoline‐type ligand 2‐(4‐diethylamino‐2‐hydroxyphenyl)‐4‐methyl‐1,2‐dihydroquinazoline 3‐oxide (HL1; H is the deprotonatable hydrogen) was prepared. Two 2‐D supramolecular complexes [Cu2(L2)2(NO3)2] (1) and [Ni2(L2)2(CH3COO)2] (2) (L2 = 1‐(2‐{[(E)‐(4‐diethylamino‐2‐hydroxybenzylidene]amino} phenyl)ethanone oxime) were synthesized using HL1 and characterized by elemental analysis, spectroscopic methods, and single‐crystal X‐ray diffraction studies. It revealed that 1 had coordinated two nitrate ions whereas 2 had acetate ions. In the crystal structures, six‐coordinated Cu (II) complex 1 formed an infinite 2‐D and X‐shaped 3‐D supramolecular frameworks. Simultaneously, Ni (II) complex 2 assembled into wavy 2‐D networks. Furthermore, electrochemical properties and antimicrobial activities of all compounds were as well investigated. Afterwards, the electrophilic and nucleophilic attack sites identified by electrostatic potential (ESP) calculations confirmed that hydrogen bonds were observed in the optimized structure of the crystal, and the closest contact between the active atoms of both complexes was confirmed through Hirshfeld surface analysis and time‐dependent density functional theory (TD‐DFT) calculations. [ABSTRACT FROM AUTHOR]

• The Cd(II) coordination polymer was synthesized and structural characterized by spectroscopic methods and single-crystal X-ray diffraction. • The solid-state luminescence properties of L and Cd(II) coordination polymer were measured. • Time dependent DFT calculations on the optimized structure of the Cd(II) complex allowed for the assignment of specific electronic transitions in the UV–Vis spectrum. • The calculated HOMO and LUMO energies show the character of the Cd(II) complex and the nucleophilic and electrophilic attack sites were confirmed with electrostatic potential (ESP) calculations. • Non-covalent supramolecular interactions in the crystal structure were quantified by means of Hirshfeld surface analysis. A novel 1-D, 2-D, 3-D supramolecular cadmium(II) coordination polymer [Cd(L) 4 (NO 3) 2 ] n (L = 4-methyl-2-(pyridin-3-yl)-1,2-dihydroquinazoline N3-oxide) was synthesized and characterized by elemental analysis and spectroscopic methods at solid-state, as well as determined by X-ray crystallographic. X-ray structure revealed that had 4:1 ligand-to-metal ratio and was best described as slight distorted octahedral geometry with six-coordinated environment. In particular, it fostered into an infinite one-dimensional (1-D) chains coordination polymer without any non-covalent interactions. The geometry optimization and HOMO, LUMO energies level calculations were performed using DFT methods. Specifically, the electronic transitions and spectral features were carried out by TD-DFT calculations. The electrostatic potential (ESP) analysis was utilized to visualize electrophilic and nucleophilic attack sites on the molecule, which verified the existence of hydrogen bonds in the optimized geometry. In addition, the solid-state luminescence and electrochemical property of Cd(II) complex was also investigated. The non-covalent interactions of Cd(II) coordination polymer was quantified with Hirshfeld surface analysis using the CrystalExplorer program. A new 1D chain Cd(II) coordination polymer, [Cd(L) 4 (NO 3) 2 ] n , was synthesized and characterized by elemental analysis and spectroscopic methods at solid-state. The Cd(II) coordination polymer was in six-coordinated environment and developed into an infinite 1-D chain, 2-D layer and 3-D supramolecular framework. The structural of Cd(II) coordination polymer have been amended markedly and the HOMO, LUMO energies level were calculated by TD/DFT. The electrostatic potential (ESP) calculations were utilized to analyse electrophilic and nucleophilic attack sites on the molecule. The consequence of cyclic voltammetry of Cd(II) coordination polymer revealed an irreversible couple Cd(II)/Cd(0) reduction process. The non-covalent interactions were quantified with Hirshfeld surfaces using the CrystalExplorer program. [Display omitted] [ABSTRACT FROM AUTHOR]