Hui-Fen Qian

Two pairs of 1:2 nickel(II) and copper(II) metal-complex dyes showing the same trans configuration and azo–hydrazone transformation but different thermal properties

Two pairs of 1: 2 neutral trans mononuclear transition-metal (M = Ni(II) and Cu(II)) complexes of pyridine-2,4-dione and quinoline-2,4-dione based heterocyclic dyes have been structurally and spectrally characterized and compared herein. X-ray single-crystal diffraction analyses of four complexes, namely trans-[Ni(La)2(DMF)2] (1), trans-[Cu(La)2(DMF)2] (2), trans-[Ni(Lb)2(DMF)2] (3) and trans-[Cu(Lb)2(DMF)2] (4), reveal that they have the same trans configuration between the bidentate chelating dianionic ligands and two axially coordinated DMF molecules. Furthermore, a transformation from the hydrazone to azo configuration has been observed for both bidentate chelating ligands La(-) and Lb(-) after metal-ion complexation. More importantly, the simultaneous DSC/TG-MS-FTIR method has been used to explore the thermal stability of four neutral metal-complex dyes 1-4, where the two axially coordinated DMF molecules in Ni(II) and Cu(II) complexes exhibit distinguishable decomposition behavior because of their different M-O bond lengths originating from the Jahn-Teller distortions.

Influence of the pendant arm, halide, and solvent on high-efficient-tuning [1 + 1] and [2 + 2] schiff-base macrocyclic complexes via a zinc-ion template.

A series of pendant-armed Schiff-base macrocyclic complexes 1-7 have been prepared by the condensation between extended dialdehydes with pendant arms (H2hpdd/H2pdd) and 1,3-propanediamine in the presence of ZnX2 (X = Cl, Br, I), where 18-membered [1 + 1] mononuclear and 36-membered [2 + 2] half-fold trinuclear macrocyclic zinc(II) complexes are yielded. Three experimental variables, i.e., the pendant arm, halide, and solvent, are found to influence the organization of final macrocyclic complexes, in addition to the conventional metal-ion template effect promoting reversible formation and cleavage of Schiff-base imine bonds. It is noted that all of the reactions produce singular macrocyclic complexes in high yields if the experimental variables are fixed, and the selection of different pendant arms and halide counterions will generate different [1 + 1] mononuclear and [2 + 2] trinuclear macrocyclic zinc(II) complexes. More interestingly, [1 + 1] and [2 + 2] macrocyclic zinc(II) complexes 2 and 3 can be produced in methanol and ethanol, respectively, in the case of the reaction between ZnBr2, H2pdd, and 1,3-propanediamine. Further experiments reveal that red solid 2 and yellow-green solid 3 can be transformed to each other just by altering the type of solvent, and this tuning is complete and reversible.

Synthesis and crystal structure of a novel chiral nickel(II) complex [Ni(L)2]Cl2.2H2O (L = D-(+)-1,2,2-trimethylcyclopentane -1,3-diamine)

Abstract A novel chiral nickel(II) complex formulated as [Ni(L)2]Cl2·2H2O (L= d -(+)-1,2,2-trimethylcyclopentane-1,3-diamine) (1) has been synthesized and characterized. X-ray single crystal determination of 1 reveals that the center Ni(II) has four-coordinate square planar coordination geometry. Three kinds of intermolecular hydrogen bonding interactions leading to three eight-membered rings are observed in the crystal structure of 1. It is also the first d -(+)-1,2,2-trimethylcyclopentane-1,3-diamine complex that has been determined crystallographically.

A rare case of a dye co-crystal showing better dyeing performance

A rare case of a pyridine-2,4-dione based heterocyclic dye co-crystal, composed of a 1 : 1 molar ratio of two structural analogs (pyridine N-Me and N-Et substituents) in the hydrazone form, is described with better dyeing performance, and this dye co-crystal can be prepared by both recrystallization in solution and solid-state co-sublimation methods.

2,4-Diamino-6-methyl-1,3,5-triazin-1-ium nitrate.

In the title salt, C4H8N5 +·NO3 −, a ring N atom of 2,6-diamino-4-methyltriazine is protonated. Each anion is connected to three neighbouring cations by multiple N—H⋯O hydrogen bonds which, together with N—H⋯N contacts, generate a layer structure.

2,4-Diamino-6-methyl-1,3,5-triazin-1-ium chloride

In the title compound, C4H8N5 +·Cl−, a two-dimensional layer packing network is observed in which every chloride anion links three adjacent 2,4-diamino-6-methyl-1,3,5-triazin-1-ium cations by N—H⋯Cl hydrogen-bonding interactions, forming 12-membered and eight-membered hydrogen-bonded rings with graph-set motifs R 4 4(12) and R 3 3(8), respectively. In addition, N—H⋯N hydrogen bonds are found between adjacent cations, forming another type of eight-membered [R 2 2(8)] hydrogen-bonded ring.

3,5-Dibromo-2-hydroxy­benzaldehyde

The title compound, C7H4Br2O2, exhibits a layer packing structure via weak π–π stacking interactions [centroid–centroid distances between adjacent aromatic rings are 4.040 (8) and 3.776 (7) Å]. Molecules in each layer are linked by intermolecular O—H⋯O hydrogen bonding and Br⋯Br interactions [3.772 (4) Å]. There are two molecules in the asymmetric unit.

Syntheses, characterizations of copper compounds containing a series of S-, N-containing aromatic heterocyclic 2,2′:6′,2″-terpyridine derivatives

Abstract A series of 2,2′:6′,2″-terpyridine (TPY) based aromatic heterocyclic compounds, extended by thiophene, 4-dibenzothiophene, and thiazole units at the para position of the central pyridine ring in TPY, are described in this paper. A new compound, 4′-(4′-dibenbenzothiophene-5-thiophene-2-yl)-2,2′:6′,2″-terpyridine (La), serves as a tridentate ligand to react with Cu(NO3)2·3H2O and CuCl2·2H2O, respectively, to produce two different Cu(II) complexes [Cu(La)2](NO3)2 and [CuLaCl2] with 1 : 2 and 1 : 1 metal/ligand ratios. Dibenzothiophene is first introduced to TPY via the thiophene bridge. The alterations in cis and trans configuration, dihedral angles between adjacent aromatic rings, and photophysical properties have been observed before and after Cu(II) complexation, which has been verified by their crystal structures, UV–vis and fluorescence spectra.

Biphenyl-3,3′,4,4′-tetra­amine

The title compound, C12H14N4, has a crystallographically imposed centre of symmetry. Intermolecular N—H⋯N hydrogen bonds between amino groups link adjacent molecules into a three-dimensional network where ten-membered hydrogen-bonded rings are observed.

Zinc(II) and cadmium(II) complexes having racemic and enantiomeric ligands: [Zn(La)2](NO3)2 · CH3CH2OH and [Cd(Lb)2Cl](ClO4) (La = D,L and Lb = D-(+)-1,2, 2-trimethylcyclopentane-1,3-diamine)

Two d10 transition-metal complexes having racemic and enantiomeric 1,2,2-trimethylcyclopentane-1,3-diamine ligands, [Zn(La)2](NO3)2 · CH3CH2OH (1) and [Cd(Lb)2Cl](ClO4) (2) (La = D,L-1,2,2-trimethylcyclopentane-1,3-diamine, Lb = D-(+)-1,2,2-trimethylcyclopentane-1,3-diamine or (1R,3S)-1,2,2-trimethylcyclopentane-1,3-diamine), were synthesized and characterized by X-ray single-crystal diffraction. They crystallize in the Pbca and P212121 space groups, respectively, and have different coordination numbers and coordination geometry (four-coordinate tetrahedron for Zn(II) in 1 and five-coordinate square-based pyramid for Cd(II) in 2) mainly due to their different ionic radii.