Yi-Fen Hsu

Ligand isomerism-controlled structural diversity of cadmium(II) perchlorate coordination polymers containing dipyridyladipoamide ligands

The syntheses, structures and ligand conformations of three Cd(II) coordination polymers [Cd(L1)(ClO4)2]∞ [L1 = N,N′-di(2-pyridyl)adipoamide], 1, {[Cd(L2)2(CH3OH)2](ClO4)2·2CH3OH}∞ [L2 = N,N′-di(3-pyridyl)adipoamide], 2 and [Cd(L3)2(ClO4)2(CH3CH2OH)2]∞ [L3 = N,N′-di(4-pyridyl)adipoamide], 3, are reported. Their structures have been characterized by X-ray crystallography. Complex 1 forms 1D zigzag chains, while complex 2 forms 2D pleated sheets which are positioned in an ABAB manner. Complex 3 shows a rare 3D entanglement from parallel polycatenation of 3-fold interpenetrated square layers. While the L1 ligands in 1 adopt AAAtrans conformations and the L2 ligands in 2 adopt GAGtrans conformations, the L3 ligands in 3 adopt AAAtrans and AGAtrans conformations. The structural types of the Cd(II) coordination polymers can be directed by ligand isomerism.

Roles of halide anions in the structural diversity of Zn(II) complexes containing the flexible N,N′-di(4-pyridyl)adipoamide ligand

A series of Zn(II) complexes with N,N′-di(4-pyridyl)adipoamide ligands, {[ZnX2(L)]·H2O}∞ (X = Cl, 1, Br, 2 and I, 3; L = N,N′-di(4-pyridyl)adipoamide), [Zn2X4(L)2]·2DMF (X = Cl, 4 and Br, 5) and [Zn2I4(L)2]·4DMF·C4H10O, 6, were prepared and their structures determined by X-ray crystallography. Complexes 1 and 2 form double-stranded helical chains which are supported by the N–H⋯O and O–H⋯X hydrogen bonds involving the guest water molecules and the halide anions, whereas 3 shows sinusoidal chains which are interlinked by the N–H⋯O hydrogen bonds and π–π interactions. Complexes 1–3 represent a unique example that the halide anions show significant effect on folding and unfolding of the Zn(II) double-stranded helical coordination polymers. Complexes 1–3 can be transformed to the corresponding complexes 4–6, which are dinuclear with 34-membered metallocycles. In these complexes, the chloride and bromide anions play the same role in the crystal structures, while the iodide anion is distinct.

Hg(II) supramolecular isomers: structural transformation and photoluminescence change

Two pairs of Hg(II) supramolecular isomers, [HgBr2(GAG-L)]∞ [L = N,N′-di(3-pyridyl)adipoamide], 1, and [HgBr2(AAA-L)]∞, 2, and [HgI2(GAG-L)]∞, 3, and [HgI2(AAA-L)]∞, 4, have been successfully synthesized by various methods and structurally characterized by single-crystal X-ray crystallography. Complex 1 forms a one-dimensional (1D) meso-helical chain, 2 and 4 exhibit normal 1D helical chains, while 3 displays a 1D sinusoidal chain. The L ligands in 1 and 3 display GAG trans syn–syn conformation, while those in 2 and 4 adopt the AAA trans syn–syn conformation. In addition, complexes 1 and 3 can be irreversibly transformed to 2 and 4, respectively, under simple heating or hydrothermal condition. Moreover, complex 1 exhibits intense violet-blue photoluminescence in the solid state, whereas 2 and 3 display weak broad emissions in the blue-green region and 4 shows undetectable emission intensity.

Synthesis and crystal structure of 2-D silver coordination polymers containing aminopyrazine

Two supramolecules of Ag(I), [Ag(NO3)(APZ)] n (1) and {[Ag(APZ)2][CF3COO] · H2O} n (2) (APZ = aminopyrazine) have been prepared by self-assembly of Ag(I) salts with APZ in MeOH/H2O. EA, IR, and TGA spectra have been recorded and the complexes have been structurally characterized by X-ray crystallography, confirming that 1 and 2 are 2-D pleated rectangular grid coordination polymers. The in 1 is coordinated to Ag+, bidentate, and μ2,η1- , while CF3COO− in 2 is not coordinated. Ag ··· O interactions, hydrogen bonds, and π ··· π stacking interactions support the supramolecular structures.