Synthesis, structure and photophysical properties of two tetranuclear copper(I) iodide complexes based on acetylpyridine and diphosphine mixed ligands.

Two copper(I) iodide tetramers, namely, [µ2-1,3-bis(diphenylphosphanyl)propane-κ2P:P']di-µ3-iodido-di-µ2-iodido-[1-(pyridin-3-yl)ethan-1-one-κN]tetracopper(I) dichloromethane disolvate, [Cu4I4(C6H7NO)2(C27H26P2)2]·2CH2Cl2 (CuL3), and [µ2-1,3-bis(diphenylphosphanyl)propane-κ2P:P']di-µ3-iodido-di-µ2-iodido-[1-(pyridin-4-yl)ethan-1-one-κN]tetracopper(I), [Cu4I4(C6H7NO)2(C27H26P2)2] (CuL4), have been synthesized from reactions of CuI, 1,3-bis(diphenylphosphanyl)propane (dppp) and 3- or 4-acetylpyridine (3/4-acepy). The complexes were characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction (XRD), powder XRD and photoluminescence spectroscopy. Both complexes possess a stair-step [Cu4I4] cluster structure with a crystallographic inversion centre located in the middle of a Cu2I2 ring (Z' = 1/2). The dppp ligands each adopt a bidentate coordination mode that bridges two CuI centres on one side of the [Cu4I4] cluster and the acepy ligands act as terminal ligands. The solid-state samples of similar complexes show highly efficiency thermally activated delayed fluorescence (TADF) at room temperature. At ambient temperature, both CuL3 and CuL4 exhibit photoluminescence, with a maximum emission in the region 560-580 nm and with short emissive decay times, but only phosphorescence was observed at 77 K. The narrow gaps between the higher lying singlet state and the triplet state, ΔE(S1 - T1), also confirm the presence of TADF. Structure analysis and consideration of photoluminescence indicates that the position of the acetyl group on the heterocyclic ligand has an obvious influence on the structural arrangement, on intermolecular interactions and on the observed photophysical properties.

Solvent-assisted planar structure of a stilbene-based salicylhydrazone compound: crystal structure, solvent- and aggregation-induced emission, and switchable luminescence colouration.

A novel stilbene-based salicylhydrazone compound {systematic name: (E)-4,4'-(ethene-1,2-diyl)bis[(N'E)-N'-(2-hydroxybenzylidene)benzohydrazide] dimethyl sulfoxide disolvate, C30H24N4O4·2C2H6OS or L·2DMSO} was synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction and luminescence spectroscopy. The title compound crystallizes in the monoclinic space group P21/c, with half a symmetry-independent L molecule and one dimethyl sulfoxide (DMSO) solvent molecule in the asymmetric unit. The L molecule adopts an almost planar structure, with a small dihedral angle between the planes of the stilbene and salicylhydrazone groups. There are multiple π-π stacking interactions between adjacent L molecules. The DMSO solvent molecules act as proton donors and acceptors, forming hydrogen bonds of various strengths with the L molecules. In addition, the geometry optimization of a single molecule of L and its luminescence properties either in solution, as a solvated solid or as a desolvated solid were studied. The compound shows an aggregation-induced emission (AIE) effect and exhibits switchable luminescence colouration in the solid state by the simple removal or re-addition of the DMSO solvent.

Four isostructural lanthanide(III) coordination compounds based on a new N-oxydic pyridyl naphthalenediimide ligand: synthesis and characterization.

Naphthalenediimides, an attractive class of electron-deficient organic dyes with rich redox and photoredox properties, have been investigated extensively as building blocks for coordination networks or metal-organic frameworks in recent decades. However, most of the available work has focused on d-block metal cations rather than f-block lanthanide ions, whose complexes exhibit a large variability in coordination numbers. In this article, four coordination polymers composed of naphthalenediimides and lanthanide cations, namely catena-poly[[[tris(nitrato-κ2O,O')lanthanide]-bis{µ-N,N'-bis[(1-oxidopyridin-1-ium-3-yl)methyl]-1,8:4,5-naphthalenetetracarboxdiimide-κ2O:O'}-[tris(nitrato-κ2O,O')lanthanide]-µ-N,N'-bis[(1-oxidopyridin-1-ium-3-yl)methyl]-1,8:4,5-naphthalenetetracarboxdiimide-κ2O:O'] methanol disolvate], {[Ln(C26H16N4O4)1.5(NO3)3]·CH3OH}n, with Ln = Eu, 1, Gd, 2, Dy, 3, and Er, 4, have been successfully synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analyses revealed that the four compounds are isomorphic and that each asymmetric unit contains one nine-coordinated Ln centre, one and a half diimide ligands, three nitrate anions and one uncoordinated methanol molecule. In addition, each metal centre is surrounded by nine O atoms in a distorted tricapped trigonal-prismatic geometry. Two centres are bridged by two cis ligands to form a ring, which is further bridged by trans ligands to generate one-dimensional chains. Neighbouring chains are stacked via π-π interactions between pyridine rings to give a two-dimensional structure, which is stabilized by π-π interactions between naphthalene rings, forming the final three-dimensional supermolecular network. Solid-state optical diffuse-reflectance spectral studies indicate that compound 4 is a potential wide band gap semiconductor.

A series of pure-blue-light emitting Cu(i) complexes with thermally activated delayed fluorescence: structural, photophysical, and computational studies.

Four mononuclear Cu(i)-halide complexes containing phosphines and pyridine ligands with strong electron donor substituents, [CuCl(PPh3)2(4-NMe2py)] (1), [CuI(PPh3)2(4-NH2py)] (2), [CuI(POP)(4-NH2py)] (3), and [CuI(POP)(4-NMe2py)]·0.5(Et2O) (4), (PPh3 = triphenylphosphine, 4-NMe2py = 4-(dimethylamino)pyridine, POP = bis[(2-diphenyl-phosphino)phenyl]ether, 4-NH2py = 4-aminopyridine, Et2O = diethyl ether) were synthesized and studied with regard to their structural, photophysical properties and theoretical calculations. The complexes exhibit pure blue thermally activated delayed fluorescence (λmax = 442 (1), 436 (2), 464 (3), and 448 nm (4)) in crystalline at room temperature. Emission lifetime analyses and density functional theory (DFT) calculations show that the blue-light emission at room temperature is the singlet (metal + halide)-to-ligand charge transfer state, (1(M + X)LCT), while that at 77 K is the state of 3(M + X)LCT transition character, owing to the small singlet-triplet energy gaps (ΔE = 660-1680 cm-1). X-ray diffraction structure analysis, photophysical studies and theoretical calculations suggest that the much larger torsion angle between the N-heterocyclic rings and N-Cu-X planes of complex 3 than that of 1, 2 and 4 might causes the bathochromic shift of luminescence, although these complexes containing similar heterocycle ligands.

A two-dimensional silver(I) coordination polymer constructed from 4-aminophenylarsonate and triphenylphosphane: poly[[(µ3-4-aminophenylarsonato-κ³N:O:O)(triphenylphosphane-κP)silver(I)] monohydrate].

The title compound, {[Ag(C6H7AsNO3)(C18H15P)]·H2O}n, has been synthesized from the reaction of 4-aminophenylarsonic acid with silver nitrate, in aqueous ammonia, with the addition of triphenylphosphane (PPh3). The Ag(I) centre is four-coordinated by one amino N atom, one PPh3 P atom and two arsonate O atoms, forming a severely distorted [AgNPO2] tetrahedron. Two Ag(I)-centred tetrahedra are held together to produce a dinuclear [Ag2O2N2P2] unit by sharing an O-O edge. 4-Aminophenylarsonate (Hapa(-)) adopts a µ3-κ(3)N:O:O-tridentate coordination mode connecting two dinuclear units, resulting in a neutral [Ag(Hapa)(PPh3)]n layer lying parallel to the (101̄) plane. The PPh3 ligands are suspended on both sides of the [Ag(Hapa)(PPh3)]n layer, displaying up and down orientations. There is an R2(2)(8) hydrogen-bonded dimer involving two arsonate groups from two Hapa(-) ligands related by a centre of inversion. Additionally, there are hydrogen-bonding interactions involving the solvent water molecules and the arsonate and amine groups of the Hapa(-) ligands, and weak π-π stacking interactions within the [Ag(Hapa)(PPh3)]n layer. These two-dimensional layers are further assembled by weak van der Waals interactions to form the final architecture.

A three-dimensional coordination polymer based on the Zn4(µ3-OH)2 unit: poly[[(µ4-benzene-1,4-dicarboxylato)bis(µ3-benzene-1,4-dicarboxylato)bis(µ3-hydroxido)bis(1,10-phenanthroline-5,6-dione)tetrazinc] dihydrate].

The title compound, {[Zn4(C8H4O4)3(OH)2(C12H6N2O2)2]·2H2O}n, has been prepared hydrothermally by the reaction of Zn(NO3)2·6H2O with benzene-1,4-dicarboxylic acid (H2bdc) and 1,10-phenanthroline-5,6-dione (pdon) in H2O. In the crystal structure, a tetranuclear Zn4(OH)2 fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN2O4] octahedron and a [ZnO4] tetrahedron bridged by a µ3-OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN2O4] octahedron. The two crystallographically independent bdc(2-) ligands are fully deprotonated and adopt µ3-κO:κO':κO'' and µ4-κO:κO':κO'':κO''' coordination modes, bridging three or four Zn(II) cations, respectively, from two Zn4(OH)2 units. The Zn4(OH)2 fragment connects six neighbouring tetranuclear units through four µ3-bdc(2-) and two µ4-bdc(2-) ligands, forming a three-dimensional framework with uninodal 6-connected α-Po topology, in which the tetranuclear Zn4(OH)2 units are considered as 6-connected nodes and the bdc(2-) ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn4(OH)2 unit and are connected to it through hydrogen-bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π-π interactions between the pdon and µ4-bdc(2-) ligands.

Enantioselective synthesis of a chiral coordination polymer with circularly polarized visible laser.

Circular dichroism is known to be the feature of a chiral agent which has inspired scientist to study the interesting phenomena of circularly polarized light (CPL) modulated molecular chirality. Although several organic molecules or assemblies have been found to be CPL-responsive, the influence of CPL on the assembly of chiral coordination compounds remains unknown. Herein, a chiral coordination polymer, which is constructed from achiral agents, was used to study the CPL-induced enantioselective synthesis. By irradiation with either left-handed or right-handed CPL during the reaction and crystallization, enantiomeric excesses of the crystalline product were obtained. Left-handed CPL resulted in crystals with a left-handed helical structure, and right-handed CPL led to crystals with a right-handed helical structure. It is exciting that the absolute asymmetric synthesis of a chiral coordination polymer could be enantioselective when using CPL, and provides a strategy for the control of the chirality of chiral coordination polymers.

An unusual double T5(2) water tape trapped in silver(I) coordination polymer hosts: influence of the solvent on the assembly of Ag(I)-4,4'-bipyridine chains with trans-cyclohexanedicarboxylate and their luminescent properties.

In this paper, four silver(I) compounds, namely, {[Ag(4)(bipy)(4)(chda)]·2NO(3)·10H(2)O}(n) (1), {[Ag(2)(bipy)(2)(chda)]·14H(2)O}(n) (2), {[Ag(2)(bipy)(2)(chda)]·3EG·2H(2)O}(n) (3) and {[Ag(2)(bipy)(2)(chda)]·H(2)chda}(n) (4) (where bipy = 4,4'-bipyridine, H(2)chda = trans-cyclohexane-dicarboxylate and EG = ethylene glycol), have been synthesized and characterized by single-crystal X-ray diffraction analyses. In all of these compounds, the Ag(I) centers are linked by bipy ligands to form 1D Ag(I)-bipy chain structures. The chda(2-) anions of compound 1 adopt a µ(4)-coordination mode to connect the Ag(I)-bipy chains, forming a H-beam-like chain. In 2, the chda(2-) anions adopt a µ(2)-coordination mode to connect the Ag(I)-bipy chains resulting in two distinct 2D brick wall-like layers. These layers are further stacked in an ···ABAB··· fashion through interlayer π···π stacking interactions giving rise to a 3D framework consisting of quasi-rectangular channels, in which an unusual double T5(2) water tape is trapped. For 3 and 4, the chda(2-) anions show a similar µ(4)-coordination mode to that of 1 and connect the Ag(I)-bipy chains to form 2D grid layers with identical compositions and connective topologies. The experimental studies show that the final structures are greatly influenced by the molar ratio of the components and the solvents, which can be rationally interpreted by the existence of various supramolecular interactions between the host and guest molecules within these compounds through a systematic structural comparison. Additionally, the thermal stability and luminescent properties of these compounds were also studied.

Mu2-acetato-kappa(2)O:O'-tris(mu2-ferrocenecarboxylato-kappa(2)O:O')bis[(N,N-dimethylformamide-kappaO)copper(II)].

The title compound, [Cu(2)Fe(3)(C(5)H(5))(3)(C(2)H(3)O(2))(C(6)H(4)O(2))(3)(C(3)H(7)NO)(2)], belongs to the classic dimeric paddle-wheel structure type. It is an unusual example in that it contains two different carboxylate groups, viz. ferrocenecarboxylate and acetate. With three ferrocenecarboxylate groups and only one acetate group bridging the two Cu centres, a noncentrosymmetric molecular arrangement results.

mer-Bis(1,4-dibenzoylthiosemicarbazidato-kappa3O,N,O')cobalt(II).

The title complex, [Co(C(15)H(12)N(3)O(2)S)(2)], consists of an octahedrally coordinated Co(II) ion, with two crystallographically independent 1,4-dibenzoylthiosemicarbazidate ligands in a tridentate mer coordination [Co-O = 2.064 (3)-2.132 (3) A and Co-N = 2.037 (3)-2.043 (3) A]. There are intermolecular N-H...S hydrogen bonds involving one ligand and strong pi-pi stacking interactions involving the other ligand, resulting in a three-dimensional supramolecular framework. The hydrogen bonds and pi-pi interactions, as well as different intramolecular aryl-benzamide H-C...H(-N) distances, give rise to a difference in conformation between the two ligands.

Two pseudo-polymorphic copper-benzene-1,2,4,5-tetracarboxylate complexes.

Two pseudo-polymorphic polymers, poly[ethylenediammonium [[aquacopper(II)]-micro(4)-benzene-1,2,4,5-tetracarboxylato] dihydrate], [(C(2)H(10)N(2))[Cu(C(10)H(2)O(8))(H(2)O)].2H(2)O](n), (I), and poly[ethylenediammonium [copper(II)-micro(4)-benzene-1,2,4,5-tetracarboxylato] 2.5-hydrate], [(C(2)H(10)N(2))[Cu(C(10)H(2)O(8))].2.5H(2)O](n), (II), contain two-dimensional anionic layers, ethylenediammonium (H(2)en) cations acting as counter-ions and free water molecules. Although the topological structures of the two anionic layers are homologous, the coordination environments of the Cu(II) centres are different. In (I), the Cu(II) centre, sitting on a general position, has a square-pyramidal environment. The two independent benzene-1,2,4,5-tetracarboxylate (btc) anions rest on centres of inversion. The Cu(II) cation in (II) is located on a twofold axis in a square-planar coordination. The H(2)en cation is on an inversion centre and the btc ligand is split by a mirror plane. Extensive hydrogen-bonding interactions between the complexes, H(2)en cations and water molecules lead to the formation of three-dimensional supramolecular structures.

{[Cu(mtz)]3(CuI)}n: an unprecedented non-interpenetrated (12(3))(12(2).14)(3) network with triple-stranded helices.

A complex with triple-stranded helices, {[Cu(mtz)]3(CuI)}n, was obtained under hydrothermal conditions. The complex possesses an unprecedented non-interpenetrated (12(3))(12(2).14)3 network, which represents the first example of the largest gon value of the smallest ring for the Archimedean net reported so far.