Cao-Yuan Niu

Tuning of unusual secondary ligands to construct fluorescent zinc coordination polymers of an unsymmetrical pyridylbenzoate ligand from 1D chain to interdigital or porous 2D layers and interpenetrated 3D frameworks

Four dicarboxylic acids and nitrilotriacetic acid as secondary ligands have been used to tune the zinc(II)-organic frameworks constructed by an unsymmetrical pyridylbenzoate ligand, 3-pyrid-4-ylbenzoic acid (HL1). Interestingly, malonic acid (H2L2), nitrilotriacetic acid (H3L3), and succinic acid (H2L4), not coordinating to the metal centers and not even existing in the resultant coordination polymers can, however, tune the coordinating modes of L1 and zinc ions, and then the frameworks of their coordination polymers from interdigital 2D layers of [Zn5(L1)10(H2O)3.5]n (1), to porous 2D distorted square grids of [Zn(L1)2(H2O)1.5]n (2), and 4-fold interpenetrated 3D diamond networks of [Zn(L1)2]n (3), respectively. Especially, the topology of 1 displays an unprecedented (3,4)-connected 2D trilayer net with the Schlafli symbol of (62.8)2(6.84.10). For 2, there are 0.7 × 0.8 nm2 1D channels hosting water molecules. Besides, pimelic acids (H2L5) act as bridges for zinc dimeric constructing units and terminers for the 1D chain constructed by dimeric nodes and antiparallel double L1 spacers for [Zn2(L1)2(L5)]n (4). By contrast, terephthalic acids (H2L6) acting as bridges link similar 1D chains in 4 to construct interdigital 2D layers for [Zn2(L1)2(L6)]n (5). Finally, these five coordination polymers all exhibit strong fluorescent emissions at room temperature and high thermal stabilities.

Two cadmium(II) 1-D coordination polymers, {[Cd2(μ-Cl)4Cl2(CH3OH)(H2O)] · (H-aql)2} n and [Cd(μ-Cl)2(aql)] n : synthesis, crystal structures and fluorescent properties

Two Cd(II) 1-D chain coordination polymers with Cd–Cl-Cd–Cl 1-D chains as bases, one connected to protonated 8-aminoquinoline by intermolecular hydrogen bonds {[Cd2(μ-Cl)4(Cl)2(CH3OH)(H2O)]·(H-aql)2} n (1) (aql = 8-aminoquinoline) and the other to 8-aminoquinoline [Cd(μ-Cl)2(aql)] n (2), have been synthesized and structurally characterized by single-crystal X-ray analysis. 1 belongs to the monoclinic system with space group P2(1)/m and 2 belongs to the monoclinic system with space group C2/c. Fluorescent properties of aql, 1, and 2 showed that the fluorescence spectrum (λmax = 386 nm) of 1 is mainly of aql ππ* character. The fluorescence spectrum of 2 which emits blue-green light (λmax = 497 nm) mainly involves a metal-perturbed intraligand ππ* transition from strong covalent bonds. Thermal stabilities of 1 and 2 have also been studied.

Syntheses, Crystal Structures and Properties of Two Novel Supramolecular Complexes with α‐Thiophene Carboxylate, [Pb(phen)(tpa)2] and [Cu(im)2(tpa)2H2O] (phen=1, 10‐phenanthroline, tpa=thiophene carboxylic acid, im=imidazole)

Two novel supramolecular complexes with α‐thiophene carboxylic acid, [Pb(phen)(tpa)2] (1) and [Cu(im)2(tpa)2H2O](2), have been synthesized, their crystal structures are deterimined by X‐ray diffraction analyses, the fluorescence and thermal stable properties are researched. The crystal structure of 1 belongs to monoclinic system with space group P2(1)/c, the coordination environment around Pb(II) center is described as a distorted quadrangle pyramid geometry, two nitrogen atoms from one phen molecule and two oxygen atoms from two α‐thiophene carboxylate are located at quadrangle pyramid bottom, Pb(II) situates at pyramid top. The crystal structure of 2 belongs to monoclinic system with space group C2/c, two nitrogen atoms from two imidazole molecules and two oxygen atoms from two α‐thiophene carboxylate occupied at quadrangle pyramid bottom and oxygen atom of one water molecule located apical positions are coordinated to Cu(II) center to constructe a distorted quadrangle pyramid geometry.

N-Cyclohexyl-N-methylbenzene­sulfonamide

The title compound, C13H19NO2S, was synthesized by the reaction of N-cyclohexylaminebenzenesulfonamide and methyl iodide. The crystal packing is stabilized by weak intermolecular C—H⋯O hydrogen bonds.

One Cadmium(II) Complex of a New Polydentate Double Schiff Base Ligand Derived from 1,10-phenanthroline: Syntheses, Structures, and Fluorescent Property

One Cd(II) complex of a new polydentate double Schiff base ligand 1,10-phenanthroline-2,9-dicarboxaldehyde-di-picolinohydrazone (L), [Cd(L)(SCN)2], was synthesized and structurally characterized. This compound belongs to a monoclinic system with space group C2/c. In this monomer, the cadmium metal center is coordinated to four nitrogen atoms and two oxygen atoms from one organic ligand L acting as a hexadentate chelate, and two nitrogen atoms from two distinct SCN− anions, forming an uncommon distorted hexagonal bipyramid coordination geometry. Furthermore, fluorescent and thermal properties of the complex were performed on the powder sample. The complex strongly emits at 467 nm with the excitation of 410 nm and is thermally stable up to 300°C, and thus can be utilized as one potential fluorescent material.

A 4-fold interpenetrated metal-organic diamondoid framework: synthesis, crystal structure, and properties

The coordination polymer, [Cu2(bpp)4Cl2]Cl2, was prepared by self-assembly of benzo[f] [1,10]phenanthroline-6,7-dicarboxylic acid and bpp [bpp = 1,3-bis(4-pyridyl)propane] with CuCl2·2H2O, and determined by X-ray crystallographic diffraction, IR spectrum, and thermal analysis. The complex features a 3-D 4-fold interpenetrated metal–organic framework with diamondoid topology. There are two sets of diamondoid frameworks independently constructed by bpp bridging the same copper centers, and the two sets of diamondoid frameworks interpenetrate one another to form an interesting 4-fold interpenetrating 3-D architecture.

catena-Poly[[[N′-(4-cyano­benzyl­idene)nicotinohydrazide)silver(I)]-μ-N′-(4-cyano­benzyl­idene)nicotinohydrazide] hexa­fluorido­phosphate]

In the title polymer, {[Ag(C14H10N4O)2]PF6}n, each AgI ion is coordinated by two N atoms from two pyridyl rings of independent N′-(4-cyanobenzylidene)nicotinohydrazide ligands, and one N atom from one carbonitrile group of a symmetry-related ligand in a distorted T-shaped geometry. The ligands exhibit two modes of coordination. One acts as a bridge connecting Ag atoms to form one-dimensional chains along [01]. The other acts as a terminal monodentate ligand, coordinating to Ag through its pyridyl N atom. Two neighbouring antiparallel chains in the crystal are connected through N—H⋯O hydrogen bonds. Other adjacent chains are packed via Ag⋯O interactions, with Ag⋯O separations of 2.876 (2) Å. In addition, PF6 − counter-anions interact with the hydrazone groups through N—H⋯F hydrogen bonds. The PF6 − anion is disordered over two sites, with occupancies of 0.773 (8) and 0.227 (8).

One Monomer and One Dimer Cd(II) Complexes of 2,9-diethoxy-1,10-Phenanthroline by Two Different Crystallizing Methods: Syntheses, Structures, and Fluorescent Property

Two different crystallizing methods produced different structural complexes 1 and 2 using the same metal salt and the same bidentate organic ligand, 2,9-diethoxy-1,10-phenanthroline (L), in the same solvent. They are one monomer [Cd(L)2(H2O)] [CdCl4]·CH3OH (1) and one dimmer [Cd2(L)2Cl4] (2). Complex 1 is a CdII complex containing one cationic part [Cd(L)2(H2O)]2+ and one anionic part [CdCl4]2−. Complex 2 is a CdII dimer bridged by chloride atoms. Furthermore, fluorescent properties of these two coordination compounds have been measured.

Two Cd(II) Complexes with One New Polydentate Double Schiff Base Ligand Derived from 1,10-phenanthroline and Two Anionic Ligands: Syntheses, Structures, and Fluorescent Properties

Two Cd(II) coordination compounds of a polydentate double Schiff base ligand 1,10-phenanthroline-2,9-dicarboxaldehyde-di-2-hydroxybenzoylhydrazone (L), [Cd(L)(dca)2]·0.5H2O (dca = dicyanamide) (1) and [Cd(L)(SCN)2]·CHCl3·DMF (DMF = N, N′-dimethylformamide) (2) were synthesized and structurally characterized. Compounds 1 and 2 crystallized in monoclinic system with the space group C2/C and P21/n, respectively. The ligand L, acting as a hexadentate chelate, is coordinated to one Cd(II) atom with rare hexagonal bipyramid coordination geometry in these two compounds. Fluorescent measurements showed that these two compounds all strongly emit at 570 nm with the excitation of ultraviolet light at 360 nm.

Cinnamyl 2-oxo-2H-chromene-3-carboxyl­ate

The title compound, C19H14O4, was prepared by the reaction of 2-oxo-2H-chromene-3-acyl chloride with cinnamic alcohol. The whole molecule is not planar, the dihedral angle between the planes of coumarin and benzene rings being 13.94 (4)°, but the plane of the coumarin ring and that of the ester group are almost coplanar, making a dihedral angle of 2.9 (1)°. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link two molecules into dimers, and π–π stacking interactions between inversion-related rings of the coumarin groups [centroid–centroid distance 3.8380 (15) Å with a slippage of 1.535 Å], which connect the dimers into columns extending along [010].