Xin-Sheng Wan

Counteranion's effects on the structures of supramolecular silver coordination compounds of one asymmetric and one biting organic ligands

Reactions of one asymmetric ligand 1,6-dihydro-2-methyl-6-oxo-(3,4′-bipyridine)-5-carbonitrile (L1) with AgX (X = NO3−, BF4−, AsF6−, SbF6−) afforded two 1-D interpenetrating coordination polymers {[Ag2(L1)3]2·(CH3OH)3·(AsF6)4}n (1) and {[Ag2(L1)3]2·(SbF6)4}n (2), and two monomers [Ag(L1)2]·(NO3) (3) and [Ag(L1)2]·(CH3OH) (BF4) (4). The structural similarity between compounds 1 and 2, and the structural difference between compounds 1 and 2 and compounds 3 and 4 give evidences that the sizes of counteranions with the same polyhedron sometimes can not affect the supramolecular structures, but the polyhedra of counteranions sometimes can. The self-assembly of one angular ligand 1,3,4-thiadiazole-2,5-di-2-pyridyl (L2) with AgX (X = BF4−, ClO4−, PF6−, AsF6−, NO3−, SbF6−) produced five di-nuclear and one mono-nuclear silver(I) coordination compounds. In the three dinuclear compounds [Ag2(L2)2](BF4)2 (5), [Ag2(L2)2](ClO4)2 (6), and [Ag2(L2)2](PF6)2 (7), there are medium Ag–Ag interactions between two adjacent dimers, leading to a 1-D supramolecular chain. In the other two dimers [Ag2(L2)2](AsF6)2 (8) and [Ag2(L2)2](NO3)2(CH3OH) (9), however, no Ag–Ag interactions were found. When changing counteranion to the very large one SbF6−, the silver complex of L2 is a monomer [Ag(L2)2](SbF6) (10). The supramolecular structural diversity of compounds 7, 8, and 10, resulting from the volume changes of the octahedral counteranions shows that the sizes of counteranions with the same polyhedron can sometimes affect the supramolecular structures.

Syntheses and crystal structures of two Zn(II) complexes, [Zn(Fura)2(2,2′-bipy)(H2O)] and [Zn(μ-dnbc)2] (Fura=Furoic acid, 2,2′-bpy=2,2′-bipyridine, dnba=3,5-dinitrobenzoic acid)

Two Zn(II) complexes, [Zn(Fura)2(2,2′-bpy)(H2O)] (1) and [Zn(µ-dnbc)2] (2), have been synthesized and characterized by X-ray diffraction and IR spectra. 1 is a quaternary Zn(II) complex with ZnN2O3 configuration distorted square pyramid geometry; 2 is a Zn(II) coordination polymer with 1D double-helical chains bridged by 3,5-dinitrobenzoic acid.

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.

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.

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).

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.

Bis[N′-(3-cyano­benzyl­idene)isonicotino­hydrazide-κN]silver(I) trifluoro­methane­sulfonate

In the title compound, [Ag(C14H10N4O)2]CF3SO3, two N atoms from two independent pyridyl rings of two N′-3-cyanobenzylideneisonicotinohydrazide ligands coordinate to the unique AgI ion, forming a nearly linear coordination geometry. Adjacent silver complexes are primarily linked together by Ag⋯N interactions, with Ag⋯N separations of 2.877 (2) and 3.314 (2) Å. On the other hand, one CF3SO3 − anion interacts with hydrazone groups of two neighbouring ligands via N—H⋯O hydrogen bonds. These weak intermolecular interactions contribute to the formation of supramolecular chains. In addition, there are Ag⋯O interactions [2.787 (2) Å] between Ag and O atoms from adjacent chains.

Synthesis, Crystal Structure, and Fluorescence Property of a Cadmium Complex with Pyridine‐2‐carboxaldehyde‐2‐hydroxybenzoylhydrazone and 1,10‐Phenanthroline

One novel Cd(II) complex with pabh and phen, [Cd(pabh)(phen)Cl], (pabh=Pyridine‐2‐carboxaldehyde‐2‐hydroxybenzoyl hydrazone, phen=1,10‐phenanthroline), has been synthesized. The crystal structure was determined by X‐ray single crystal diffraction. It belongs to a monoclinic system with space group p21n. Fluorescence properties of complex and ligands have also been researched.

Synthesis and Crystal Structure of a Novel 1D Coordinated Polymer {[NaNi(mal)2(μ‐H2O)(H2O)3]·(H2O)2}n(H2mal=malonic acid)

A novel 1D coordinated polymer, {[NaNi(mal)2(μ‐H2O)(H2O)3] · (H2O)2}n (H2mal=malonic acid), has been synthesized and its crystal structure is determined by X‐ray diffraction analysis. Its crystal structure belongs to orthorhombic system with space group p2(1)2(1)2(1). The coordination environment around Ni(II) is described as a distorted octahedron constructed by four oxygen atoms from two trans‐coordinated malonates and two oxygen atoms from two trans‐coordinated water, in which oxygen atom of one water molecule bridges adjacent Ni2+ and Na+. Seven coordination environments around Na center are constructed by four oxygen atoms from four malonates and three oxygen atoms from three water molecules. In the crystal structure of title complex there are complicated hydrogen bonds.