Twodimensional halide perovskites synthesis optoelectronic attributes stableness and also programs

Columns bound by intermolecular N-H...O and N-H...N hydrogen bonds form a double column as the main structural motif in the noncentrosymmetric structure. Double columns in the noncentrosymmetric structure and columns in the centrosymmetric structure interact strongly within the ab crystallographic plane, forming a layer as a secondary basic structural motif. The noncentrosymmetric structure has a lower density and a lower (by 0.59 kJ mol-1) lattice energy, calculated using periodic calculations, compared to the centrosymmetric structure.Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4-2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-ylpyridine (L), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(μ-4-2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-ylpyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn2Cl4(C12H10N6)2]·2CH2Cl2, (I), the analogous chloroform monosolvate, [Zn2Cl4(C12H10N6)2]·CHCl3, (II), bis(μ-4-2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-ylpyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn2I4(C12H10N6)2]·2CH2Cl2, (III), and catena-poly[[[diiodidozinc(II)]-μ-4-2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-ylpyridine] chloroform monosolvate], [ZnI2(C12H10N6)]·CHCl3n, (IV), by solution reaction with ZnX2 (X = Cl and I) in a CH2Cl2/CH3OH or CHCl3/CH3OH mixed solvent system at room temperature. Complex (I) is isomorphic with complex (III) and has a bimetallic ring possessing similar coordination environments for both of the ZnII cations. Although complex (II) also contains a bimetallic ring, the two ZnII cations have different coordination environments. Under the influence of the I- anion and guest CHCl3 molecule, complex (IV) displays a significantly different structure with respect to complexes (I)-(III). C-H...Cl and C-H...N hydrogen bonds, and π-π stacking or C-Cl...π interactions exist in complexes (I)-(IV), and these weak interactions play an important role in the three-dimensional structures of (I)-(IV) in the solid state. In addition, the fluorescence properties of L and complexes (I)-(IV) were investigated.The dipharmacophore compound 3-cyclopropyl-5-(3-methyl-[1,2,4]triazolo[4,3-a]pyridin-7-yl)-1,2,4-oxadiazole, C12H11N5O, was studied on the assumption of its potential biological activity. AA-673 Two polymorphic forms differ in both their molecular and crystal structures. The monoclinic polymorphic form was crystallized from more volatile solvents and contains a conformer with a higher relative energy. The basic molecule forms an abundance of interactions with relatively close energies. The orthorhombic polymorph was crystallized very slowly from isoamyl alcohol and contains a conformer with a much lower energy. The basic molecule forms two strong interactions and a large number of weak interactions. Stacking interactions of the `head-to-head' type in the monoclinic structure and of the `head-to-tail' type in the orthorhombic structure proved to be the strongest and form stacked columns in the two polymorphs. The main structural motif of the monoclinic structure is a double column where two stacked columns interact through weak C-H...N hydrogen bonds and dispersive interactions. In the orthorhombic structure, a single stacked column is the main structural motif. Periodic calculations confirmed that the orthorhombic structure obtained by slow evaporation has a lower lattice energy (0.97 kcal mol-1) compared to the monoclinic structure.By the reaction of benzoyl chloride, potassium isothiocyanate and the appropriate halogenoaniline, i.e. 2/3/4-(bromo/iodo)aniline, we have obtained five new 1-benzoyl-3-(halogenophenyl)thioureas, namely, 1-benzoyl-3-(2-bromophenyl)thiourea and 1-benzoyl-3-(3-bromophenyl)thiourea, C14H11BrN2OS, and 1-benzoyl-3-(2-iodophenyl)thiourea, 1-benzoyl-3-(3-iodophenyl)thiourea and 1-benzoyl-3-(4-iodophenyl)thiourea, C14H11IN2OS. Structural and conformational features of the compounds have been analyzed using X-ray diffraction and theoretical calculations. The novel compounds were characterized by solid-state IR and 1H/13C NMR spectroscopy. The conformations and intermolecular interactions, such as hydrogen bonds, π-π and S(6)...π stacking, and X...O (X = I or Br), I...S and I...π, have been examined and rationalized, together with four analogous compounds described previously in the literature. The set of nine compounds was chosen to examine how a change of the halogen atom and its position on the phenyl ring affects the molecular and crystal structures.The new quaternary thiosilicate, Li2PbSiS4 (dilithium lead silicon tetrasulfide), was prepared in an evacuated fused-silica tube via high-temperature, solid-state synthesis at 800 °C, followed by slow cooling. The crystal structure was solved and refined using single-crystal X-ray diffraction data. By strict definition, the title compound crystallizes in the stannite structure type; however, this type of structure can also be described as a compressed chalcopyrite-like structure. The Li+ cation lies on a crystallographic fourfold rotoinversion axis, while the Pb2+ and Si4+ cations reside at the intersection of the fourfold rotoinversion axis with a twofold axis and a mirror plane. The Li+ and Si4+ cations in this structure are tetrahedrally coordinated, while the larger Pb2+ cation adopts a distorted eight-coordinate dodecahedral coordination. These units join together via corner- and edge-sharing to create a dense, three-dimensional structure. Powder X-ray diffraction indicates that the title compound is the major phase of the reaction product. Electronic structure calculations, performed using the full potential linearized augmented plane wave method within density functional theory (DFT), indicate that Li2PbSiS4 is a semiconductor with an indirect bandgap of 2.22 eV, which compares well with the measured optical bandgap of 2.51 eV. The noncentrosymmetric crystal structure and relatively wide bandgap designate this compound to be of interest for IR nonlinear optics.