Hong-Yun Zhang

Homochiral coordination polymers with distorted helices consisting of achiral ligand

Reactions of achiral ligand N2,N6-bis((pyridin-2-yl)methyl)pyridine-2,6-dicarboxamide (L) with AgAsF6 and AgSbF6, respectively, produced [AgL] n · nAsF6 (1) and [AgL] n · nSbF6 (2), where helically chiral 1-D coordination polymers conglomerate through complicated supramolecular interactions to form two 3-D enantiomerically chiral architectures with unusual (10,3) nets, showing spontaneous chiral resolution. Compounds 1 and 2 emit ligand-centered violet-fluorescence with strong intensities and double peaks centered at 329 and 344 nm.

Unique Tetradentate Coordination of 2,2′-Bipyridyl-3,3′-Dicarboxylate (bpdc). Hydrothermal Synthesis and Crystal Structure of A Novel Polymeric Supramolecule [Co(bpdc)(H2O)2]n

The title complex has been synthesized using hydrothermal methods and its structure determined by X-ray diffraction. It consists of polymeric chains of [Co(bpdc)(H2O)2] units (bpdc = 2,2′-bipyridyl-3,3′-dicarboxylate) which are linked by intermolecular hydrogen bonds to form two-dimensional layer-shaped supramolecules. Each bpdc ligand bridges two cobalt(II) centers in a rare tetradentate fashion through its two pyridyl nitrogen atoms chelating to one cobalt and two carboxyl oxygen atoms to the other in the equatorial plane. The octahedral coordination of cobalt is completed by two axial water molecules.

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, structures, and properties of transition metal complexes with 2-( n -pyridyl)benzimidazole ( n = 2, 3, and 4)

Three pyridylbenzimidazoles (2-PBIM, 3-PBIM, and 4-PBIM) have been prepared (2-PBIM: 2-(2-pyridyl)-benzimidazole, 3-PBIM: 2-(3-pyridyl)-benzimidazole, 4-PBIM: 2-(4-pyridyl)-benzimidazole). Reactions of several transition metals (Cd2+, Cu2+, Fe2+) with the three ligands gave four new coordination complexes, [(Cd)2(2-PBIM)2(CH3COO)4] (1), [Cu(3-PBIM)2(CH3COO)2] · 2H2O (2), [Cu(4-PBIM)2(CH3COO)2(H2O)] · H2O (3), and [Fe(4-PBIM)2(Cl)2(H2O)2] (4), respectively. These four complexes have been characterized by X-ray crystallography, IR spectroscopy, and UV absorption spectroscopy. Thermogravimetric properties of 2 and 4 were also measured. X-ray crystallographic studies reveal that these four complexes are very different, although the ligands are similar in structure. The role of hydrogen-bonding and π–π interactions in extending dimensionality of simple complexes has been discussed.

Crystal structures and luminescence properties of two new terbium complexes with aromatic carboxylic acid

Two new terbium complexes with aromatic carboxylic acids, [(Tb)2(L1)6(H2O)4] (1) and [(Tb)2(L2)6(H2O)2(DMF)2] (2) (HL1: nicotinic acid; HL2: 4-hydroxybenzoic acid), with different coordination geometries have been synthesized and their crystal structures determined. The luminescence properties of the two complexes, including the phosphorescence lifetime, have been investigated. The effect of a secondary ligand on luminescence of the ternary terbium complex with carboxylic acid and the relationship between luminescence properties and crystal structure, including coordination mode of the carboxyl groups from HL1 and HL2 and coordination mode of a secondary ligand, are discussed.

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.

Hydrothermal Synthesis, Crystal Structure, and Properties of Nickel(II) Coordination Polymer with 2,2′‐Bipyridyl‐3,3′‐dicarboxylate

Abstract The polymeric complex [Ni(bpdc)(H2O)2] n (bpdc, 2,2′‐bipyridyl‐3,3′‐dicarboxylate dianion) which consist of [Ni(bpdc)(H2O)2] units was synthesized using a hydrothermal method. Its crystal structure was determined by x‐ray crystal diffraction as 1‐D chain‐like polymer. In [Ni(bpdc)(H2O)2] n , each bpdc bridges a Ni(II) pair in a unique tetradentate fashion through its two pyridine nitrogen atoms and two oxygen atoms of two carboxyl groups. Each Ni(II) cation has a slightly distorted octahedral coordination environment where the equatorial plane includes the two nitrogen atoms of one bpdc ligand and two oxygen atoms of another bpdc anion, while the axial positions are occupied by two oxygen atoms of two coordinated water molecules. In the polymeric complex the complicated hydrogen‐bonding network and π–π stacking interaction play an important role for its thermostability.

trans-Diaqua­bis[5-carb­oxy-2-(3-pyrid­yl)-1H-imidazole-4-carboxyl­ato-κ2N3,O4]iron(II)

In the title complex, [Fe(C10H6N3O4)2(H2O)2], the FeII atom is located on an inversion centre and is trans-coordinated by two N,O-bidentate 5-carboxy-2-(3-pyridyl)-1H-imidazole-4-carboxylate ligands and two water molecules, defining a distorted octahedral environment. A two-dimensional network of N—H⋯O and O—H⋯O hydrogen bonds extending parallel to (110) helps to stabilize the crystal packing.

Synthesis, crystal structure and characterization of a 1D chain coordination polymer of zinc(II) with aroylamide, [Zn(H2bpb)Cl2] n · CH3OH, (H2bpb = 1,2- bis (3-pyridylcarboxamide)benzene)

A four-coordinate zinc(II) coordination polymer, [ZnCl2(H2bpb)] n · CH3OH (H2bpb = 1,2-bis(3-pyridylcarboxylamide)benzene), has been prepared and the crystal structure determined by X-ray diffraction. It crystallizes in the triclinic system, space group with a = 7.898(3) Å, b = 11.792(4) Å, c = 11.911(4) Å, α = 76.051(4)°, β = 89.919(4)°, γ = 78.267(4)°, V = 1052.9(7) Å, Z = 2. The crystal structure consists of chains of complex zig-zaging along the b lattice translation. Fluorescent and thermal properties of the complex were also investigated.

Studies on Synthesis and Crystal Structures of Heteronuclear Complexes of Tartarate with Na(I), K(I) and Cu(II)

A unique heteronuclear tartaric coordination complex [C12H20Cu2KNaO24] was synthesized by the interaction of potassium‐sodium tartarate with CuCl2. Its X‐ray crystal structure shows that the new coordination complex belongs to a monoclinic system, P2(1) space group. The crystallographic data are: a=7.6429(15)Å, b=20.753(4) Å, c=8.1058(16)Å, α=90°, β=112.06(3)°, γ=90°. In this complex, two Cu(II) ions that are in different coordination environments and 2 tartarate ligands exist in cyclic forms. These cyclic structures are connected by Na(I)–K(I) ion pairs and then form the complicated crystal structure through the hydrogen‐bond network.