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In the title compound, C20H18N4, the benzene ring lies about an inversion center. The central benzene-1,4-diamine unit is connected to two pyridine rings by the C=N imine bonds. The dihedral angle between the benzene and pyridine rings is 82.9 (1)°.

In the title compound, C15H16N2, has an E conformation about the central N=C bond. The benzene and pyridine rings are almost normal to one another with a dihedral angle of 87.47(8)°. In the crystal, there are no classical hydrogen bonds.

In the title centrosymmetric dinuclear complex, [Eu2(CH3CO2)6(C12H8N2)2], the EuIII atom is nine-coordinated by two N atoms from a 1,10-phenanthroline ligand and seven O atoms from five acetate ligands (two bidentate, three monodentate). The crystal structure is stabilized by π–π stacking interactions between the pyridine and benzene rings of adjacent molecules, with a centroid–centroid distance of 3.829 (2) Å.

The molecule of the title compound, C23H23N3, which was synthesized by the condensation reaction between 2,6-diacetylpyridine and 2-dimethylaniline, adopts an E configuration about both C=N imine bonds. The dihedral angles formed by the benzene rings with the pyridine ring are 89.68 (5) and 53.62 (6)°.

The title compound, C29H35N3, is the product of the condensation reaction between 2,6-diacetylpyridine and 2,6-diethylaniline. In the molecule, the pyridyl ring is coplanar with the imino functional groups [torsion angles in the range 177.1 (2)–179.9 (2)°. The two 2,6-diethyl-substituted benzene rings are approximately perpendicular to the ethylidenepyridine central core, the dihedral angles being 88.7 (1) and 88.4 (1)°, respectively.

In the title compound, C14H30N22+·2Br−·2CH3OH, two terminal C atoms of the butane chain are connected to two N atoms of the 1-methylpyrollidines, forming a linear diquaternary ammonium cation. The cation lies across a centre of inversion located between the two central C atoms of the butane chain. The asymmetric unit therefore comprises one half-cation, a bromide anion and a methanol solvent molecule. In the crystal structure, the bromide anions are linked to the methanol solvent molecules by O—H...Br hydrogen bonds.

Under the guidance of self-assembly, a series of Cu(I)/Cu(II) metal-organic complexes (MOCs), [Cu3(TCPB)2(H2O)3]·2H2O (1), {[Cu2(TCPB) (DMA)(H2O)]·H2O} n (2), [(Cu8I8) (Cu6I6)0.5(DABCO)3·2H2O] n (3), and [(Cu4I8) (DABCO)2·6H2O]2n (4) (H3TCPB = 1,3,5-tris(4-carbonylphenyloxy)-benzene, DABCO = 1,4-diazabicyclo[2.2.2]octane) have been synthesized and characterized. Complexes 1 and 2 are driven by noncovalent interactions to assemble into supramolecular metal-organic frameworks. Considering H3TCPB ligand with different geometrical structures, 1 forms an Eiffel Tower shaped supramolecular cage based on equilateral triangle shaped trinuclear [Cu3(CO2)3] unit, which possesses effective free volume about 24.7%. Changing the solvent, 2 displays 1D chain structure based on linear bivalent copper trinuclear {Cu3(CO2)2(H2O)2}. When inducing auxiliary ligand DABCO, H3TCPB serves as additive agent and 3 consists of mixed CuI clusters (Cu6I6 and Cu8I8) and plays a 2D layer, which is a rare example. Without additive agent, 4 exhibits a 2D cuprous iodide layer, where 3 and 4 are two novel copper-iodide supramolecular isomers. Owing to large voids in the framework, 1 can serve as a host for use in dye adsorption. The experiment results show that different dyes, including "just right size" Crystal Violet (CV) can be rapidly adsorbed by 1, but smaller Indigo Blue (IB), Methylene Blue (MEB), Methyl Orange (MO), and larger Rhodamine B (RB) and Methyl Blue (MB) can hardly be adsorbed. Surprisingly, 1 also preferentially adsorbs (or separates) CV from MO and CV in their mixed aqueous solution with fast response and high sensitivity (<16.13 s) by the theoretical calculation. Moreover, absorption spectra demonstrate the band gaps of 3 and 4 are 2.37 and 1.98 eV, respectively. When increasing the dimensions of inorganic compositions in cluster-organic complexes, it could exert a remarkable influence on the band gap. [ABSTRACT FROM AUTHOR]

Using five Schiff base ligands (E)-N-(pyridine-2-yl) (CH=NPhR) (where R = 4-CH3, L¹; 2,6-(CH3)2, L²; 2,4,6-(CH3)3, L³; 2,6-(C2H5)2, L4; 2,6-(i-C3H7)2, L5), nine Zn(II)/Cd(II) complexes, namely, Zn1-Zn3, Cd1, Cd2, Cd3a, Cd3b, Cd4, and Cd5, have been successfully synthesized. The structures of the Zn(II)/Cd(II) complexes have been established by single crystal X-ray diffraction and further physically characterized by ¹H NMR, FT-IR, and elemental analysis. The crystal structures of these complexes indicate that the structures of ligand and anions can directly influence the formation of 1D → 3D supramolecular metal-organic frameworks (SMOFs) via C-H⋯O/C-H⋯Cl hydrogen bonds and π⋯π interactions. Upon irradiation with UV light, the nine Zn(II)/Cd(II) complexes display deep blue emissions of 401-436 nm in acetonitrile solution and light blue or bluish green emissions of 485-575 nm in the solid state, respectively. The photoluminescence properties of nine Zn(II)/Cd(II) complexes can be finely and predictably tuned over a wide range of wavelengths by small and easily implemented changes to ligand structure. It is worth noting that Zn1 and Cd1 exhibit obvious aggregation-induced emission enhancement (AIEE) properties in the CH3CN-H2O mixture solutions. [ABSTRACT FROM AUTHOR]

Using Schiff-base ligands (E)-N-(6-methoxypyridin-2-yl)(CH=NAr) (where Ar = C6H5, L1; 2-MeC6H4, L2 ; 2,4,6-Me3C6H2, L3), six Zn(II)/Hg(II) complexes, namely, [ZnL1Cl2] (Zn1), [HgL1Cl2 (Hg1), [ZnL2Cl2 (Zn2), [HgL2Cl2] (Hg2), [ZnL3Cl2] (Zn3), and [HgL3Cl2] (Hg3) have been synthesized under solvothermal conditions. The structures of six complexes have been established by X-ray single-crystal analysis and further physically characterized by EA, FT-IR, ¹H NMR, and ESI-MS. The crystal structures of these complexes indicate that non- covalent interactions, such as hydrogen bonds, C- H---Cl, and π***π stacking, play essential roles in constructing the resulting supramolecular structures (ID for Hg3; 2D for Zn2, Hg2; 3D for Zn1, Hg1, and Zn3). Upon irradiation with UV light, the emission of complexes Zn1-Zn3 and Hg1-Hg3 could be finely tuned from green (480- 540 nm) in the solid state to blue (402- 425 nm) in acetonitrile solution. It showed that the ligand and metal cation can influence the structures and luminescence properties of complexes such as emission intensities and maximum wavelengths. Since these ligands and complexes could compensate for the absorption of N719 in the low-wavelength region of the visible spectrum and reduce charge recombination of the injected electron, the ligands L1- L3 and complexes Zn3/Hg3 were employed to prepare cosensitized dye-sensitized solar cells devices for investigating the influences of the electron-donating group and coordination on the DSSCs performance. Compared to DSSCs only being sensitized by N719, these prepared ligands and complexes chosen to cosensitize N719 in solar cell do enhanced its performance by 11- 41%. In particular, a DSSC using L3 as cosensitizer displays better photovoltaic performance with a short circuit current density of 18.18 mA cm-2, corresponding to a conversion efficiency of 7.25%. It is much higher than that for DSSCs only sensitized by N719 (5.14%). [ABSTRACT FROM AUTHOR]

A rare 3D tetranuclear {In4(μ2-OH)3} building block based MOF {[In4/3(μ2-OH)(2,6-pydc)(1,4-bda)0.5(H2O)]·2H2O}n (2) was obtained through a crystal transformation from a dimeric complex In3(2,6-pydc)3(1,4-bda)1.5(H2O)6 (1). With a 2D + 3D 3D compact structure, 2 retains crystallinity in boiling water and organic solvents, exhibiting exceptional fluorescence quenching behaviour for the DMSO molecule. [ABSTRACT FROM AUTHOR]

Five IIB group complexes, [ZnL¹Cl2] (1), {[CdL¹Cl2]}2 (2), [Cd(L¹)2(NO3)⋅H2O (3), [HgL¹Cl2] (4), and [ZnL²Cl2] (5) [L¹ = 1-[2-(6-methoxy-2-pyridylmethyl)]-2-[2-(6-methoxy-pyridyl)]benzimidazole; L² = 2-[2-(6-methoxypyridyl)]benzimidazole] have been synthesized and structurally characterized by elemental analysis, IR spectroscopy, ¹H NMR, 13C NMR and X-ray single-crystal analyses. The structural investigations testify that the ionic radius and counterions (Cl- and NO3-) cooperatively affect the coordination mode of central metal. As small and medium radii, four-coordinated Zn2+ (1 and 5) and five-coordinated Cd2+ (2) possess tetrahedron and trigonal bipyramid geometries, respectively. Though Hg2+ (4) has a larger radius, its three-coordinated geometry is trigonal planar in order to eliminate repulsive forces. Further observations illustrate that Cd2+ (3) is bound to two ligands L¹ when NO3- is the counter anion, forming seven-coordinated monocapped trigonal prismatic geometry. Complexes 1-5 display bright blue luminescence with the emission maxima (λmax) ranging from 399 to 499 nm at 298 K, depending on the N,N'-chelating ligand-centered Π* → π transition. Upon cooling to 77 K, the complexes show rich structured emission profiles compared to those at 298 K. The emission lifetimes of L and 1-5 are on the microsecond scale. The emission efficiency of 1-5 is shown by quantum yields ranging from 0.23 to 0.40. Complexes 1-5 offer a good insight into the opportunities in the utilization of blue materials for application and function. [ABSTRACT FROM AUTHOR]

In this work, we present the synthesis of three novel 3D Cd(II) coordination polymers, {[Cd(IN)2].H2O}n (1), [Cd2(IN)2(SO4)(DMF)2]n (2) and {[Cd3(IN)5.5].0.5OH-}n (3) (HIN = isonicotinic acid). Coordination polymers 1 and 2 were obtained via solvothermal reactions. The synthesis of coordination polymer 3 was realized by a simple temperature induced single crystal to single crystal transition from 1. Single-crystal X-ray diffraction analyses revealed that 1-3 exhibit three different structural types: 1 displays a (6,3)-connected rtl net with the Schläfli symbol (4.62)2 (42.610.83) constructed from mononuclear [CdO4N2] clusters with the help of HIN. 2 is defined as a 6-connected pcu net with the Schläfli symbol {412.63} which is built from binuclear [Cd2(SO2)2] clusters and HIN linkers. 3 can be regarded as a 9-connected ncd net with the Schläfli symbol {36.422.58}, which consists of paddlewheel trinuclear [Cd3(O2C)5] clusters and a bridging HIN. Coordination polymers 1-3 display luminescence with emission maxima containing deep blue, blue, light blue and green at 298 K or 77 K both in solvents (polarity: DMF > CH3OH > CH2Cl2) and in the solid state. The lifetime of all the molecules is in microsecond scale. [ABSTRACT FROM AUTHOR]

A series of five-coordinated 2,6-bis(imino)pyridyl Cu(II) complexes, [2,6-(ArN=CMe)2C5H3NCuCl2·nCH3CN] (Ar = 4-MeC6H4, n = 0.5, Cu1; Ar = 2,6-Et2C6H3, n = 1, Cu2; Ar = 2,4,6-Me3C6H2, n = 1, Cu3; Ar = 2,6-Me2C6H3, n = 0, Cu4; Ar = 2-MeC6H4, n = 1, Cu5), were synthesized in acetonitrile by reactions of the corresponding bis(imino)pyridine ligands with CuCl2·2H2O, respectively. The structures of five complexes were determined by single-crystal X-ray diffraction. In all complexes, the metal center is tridentately chelated by ligand and further coordinated by two chlorine atoms, resulting in distorted trigonal-bipyramidal geometry for Cu1, Cu3, Cu4, and Cu5, respectively, and approximately square-pyramidal geometry for Cu2. At 298K in dichloromethane solution, all complexes exhibit blue-green luminescent emissions at about 478–499nm, which could be attributed to ligand-centered π*→π transitions. However, fluorescent emission of complexes Cu1–Cu5 is significantly weaker than those of ligands, which could be attributed to fluorophore-quencher interactions via paramagnetic Cu(II) center. [ABSTRACT FROM AUTHOR]

In the title compound, [Cd(C27H31N3)Cl2]·CH3CN, the coordination geometry around the five-coordinated CdII atom can be described as distorted trigonal–bipyramidal, formed by two Cl atoms, one pyridine N and two imine N atoms from the bis(iminoalkyl)pyridine ligand. The dihedral angles between the substituted phenyl rings and the plane formed by the three coordinated N atoms are 90.6 (1) and 86.0 (1)°. C—H...Cl hydrogen bonds link the molecules into a three-dimensional supramolecular network. [ABSTRACT FROM AUTHOR]