Wen-Ting Deng

Structurally diverse copper(II) complexes with pyridazine-integrated with pyrazine–Schiff base ligand featuring an easily lost proton in the hydrazone backbone

To probe the coordination approach of pyridazine and pyrazine ligands, five new complexes of [CuII2L2Cl2] (1), [CuII(L-H)(NO3)(H2O)2](NO3)(H2O) (2), {[CuII(L-H)(H2O)](ClO4)2(H2O)}n (3), [CuII2L2(OH)](NO3)(H2O)2 (4), [CuII2L2(OH)](ClO4) (5) based on Schiff base ligand (E)-3-chloro-6-[2-(pyrazin-2-ylmethylene)hydrazinyl]pyridazine (HL) bearing pyridazinyl and pyrazinyl groups have been synthesized and characterized by IR spectra, elemental analyses, the bond valence sum (BVS) analyses, powder X-ray diffraction (PXRD) analyses, X-ray single crystal diffraction and density function theory calculations. The structures of 1, 2 and 3 suggest that the second nitrogen donors of the pyrazinyl unit can link with other metal ions to construct a higher dimensional architecture by the reaction of HL with Cu(ClO4)2 [CuCl2 for 1, Cu(NO3)2 for 2 and Cu(ClO4)2 for 3]. The structures of 4 and 5 indicate that additional donor units of the pyridazinyl chromophore can bind multiple metal ions to form a multi-metallic cluster, when the protons of the hydrazone backbones are abstracted in the presence of triethylamine to strengthen the coordination behavior of the second nitrogen atom. However, for 1, the protons of the hydrazone backbone are lost with or without triethylamine and the additional nitrogen atoms of the pyrazinyl and pyridazinyl groups are not found to connect to other metal ions, which can probably be assigned to the strong coupling effect of chlorine ions. Magnetic measurements display weak antiferromagnetic coupling between the copper(II) ions in 1 and 5, and ferromagnetic coupling in 3. In addition, the antioxidant activities of HL and 1–5 were also studied.

Pb(II) and Bi(III) complexes involving a Schiff base ligand: syntheses, structures, physical, and antioxidant properties

Two new complexes, {[PbL(NO3)2H2O]H2O}n (1) and [BiL2(NO3)2]NO3 (2), based on (E)-3-chloro-6-[2-(pyrazin-2-ylmethylene)hydrazinyl]pyridazine (L) were synthesized and characterized by IR spectra, single-crystal X-ray diffraction, and elemental analyzes. X-ray single crystal diffraction experiments of 1 and 2 display that extensive hydrogen bonds and π…π stacking interactions construct the 1-D infinite chain {[PbL(NO3)2H2O]H2O}n and [BiL2(NO3)2]NO3 into two 3-D supramolecular frameworks. Interestingly, pure phase PbO nano-particles were synthesized by thermolysis of 1 and characterized by scanning electron microscopy and X-ray powder diffraction analyzes. Furthermore, antioxidant activities of L, 1, and 2 were also studied.

Syntheses, Crystal Structures, and Photoluminescent Properties of Zn(II) and Ag(I) Coordination Polymers Based on 1H-1,2,4-triazole-1-methylene-1H-benzimidazole

The title ligand, 1H-1,2,4-triazole-1-methylene-1H-benzimida- zole (L), and its two new derivatives, [ZnL2Cl2]n (1) and [AgL(NO3)]n (2), were synthesized and characterized by X-ray single diffraction, IR and elemental analysis. Owing to the greater distribution of the electron density associated with the benzimidazoyl and triazoyl units of L, the supramolecular frameworks of L, 1, and 2 are dominated by hydrogen bonding or π…π interactions in the solid state. In additional, the photoluminescent properties of L, 1, and 2 were also described.

Synthesis, Crystal Structure, and Antibacterial and Antioxidant Properties of a New Ag(I) Coordination Polymer Based on 3-Chloro-6-(1H-1,2,4-triazol-1-yl) Pyridazine

A new Ag(I) complex [AgL2(NO3)] (1) (L = 3-chloro-6-(1H-1,2,4-triazol-1-yl) pyridazine) was synthesized and characterized by IR spectra and X-ray single-crystal diffraction. The structure reveals that each nitrate ion adopts not only bidentate chelating coordination, but also the bridging mode to connect surrounding Ag(I) atoms. Each ligand L binds three Ag(I) ions and each Ag(I) ion links three L to form a 1D chain structure. All 1D chains further construct a 3D supramolecular framework by hydrogen bonds (C-H…O) and π…π interactions (offset stacking) in the solid state. The antibacterial activity and antioxidant activity of L and 1 were also studied.

Synthesis, Crystal Structure, and Antioxidant Property of a New Co(Ш) Coordination Polymer Based on Ligand (E)-2-{2-[1-(1-methyl-1H-benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}benzo[d]thiazole

A new Co(Ш) complex, [CoL2](ClO4)(CH3CN) (1) (HL = (E)-2-{2-[1-(1- methyl- 1H-benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}benzo[d]thizole), has been prepared by solvent evaporation method, and characterized by single-crystal X-ray diffraction, bond valence sum, and elemental analysis. The result of single-crystal X-ray diffraction analysis indicates that each Co(Ш) ion is six-coordinated by six nitrogen atoms from two L− to form distorted octahedral geometry. The hydrogen bonds and π…π stacking interactions ensure the cohesion of crystal lattice in a 3D supramolecular framework in the solid state. The antioxidant activities of HL and 1 were also studied.