Yi-Feng Sun

Synthesis and crystal structure of potassium and manganese complexes of 1,2,3-triazole-4,5-dicarboxylic acid

Three coordination compounds [K(H2TDA)H2O] n (1), [K(H2TDA)(H3TDA)2H2O] n (2), and Mn2(phen)2(HTDA)2(H2O)4 (3) have been synthesized and characterized structurally by X-ray diffraction, where H3TDA = 1,2,3-triazole-4,5-dicarboxylic acid and phen = 1,10-phenanthroline. Their solid-state structures have been characterized by elemental analysis and IR spectroscopy. In 1, a 3-D (4, 8)-connected metal-organic framework has been constructed using dinuclear potassium clusters as eight-connected nodes and the ligands as four-connected nodes; it represents the fluorite topology network. Compound 2 exhibits 1-D chains along c-axis, which are connected by strong hydrogen-bond interactions in 2-D layers; the layers are further stacked via hydrogen bonds in the b-direction. In 3, two neighboring Mn(II) ions are bridged by two 1,2,3-triazole-4,5-dicarboxylic groups, forming a binuclear structure, with Mn(II) ··· Mn(II) distance of 4.356 Å, which is further linked to generate a 2-D layer structure via interdimer hydrogen bonds. The fluorescence for these compounds was investigated.

2-Phenyl-4-(3,4,5-trimethoxy­benzyl­idene)-1,3-oxazol-5(4H)-one

The title compound, C19H17NO5, was synthesized as part of a continuing project involving the structures of oxazolone derivatives. The molecule adopts a Z configuration about the central olefinic bond. The 2-phenyl ring is slightly twisted out of the plane of the oxazolone ring system by 11.2 (2)°. The crystal structure is stabilized by weak intermolecular C—H⋯O hydrogen bonds.

(E)-N′-(4-Pyridylmethyl­ene)-2-(quinolin-8-yl­oxy)acetohydrazide sesquihydrate

In the title compound, C17H14N4O2·1.5H2O, the mean planes of the pyridine ring and quinoline group make a dihedral angle of 21.0 (2)°. One water molecule lies on a twofold rotation axis. The organic molecules and the three water molecules are linked into infinite chains by N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds.

2,6‐Dimethoxy‐4‐(5‐oxo‐2‐phenyl‐4,5‐dihydro‐1,3‐oxazol‐4‐ylidenemethyl)phenyl acetate

The title compound, C20H17NO6, was synthesized by the reaction of syringaldehyde with hippuric acid. The molecule adopts a Z configuration about the central olefinic bond. The two benzene rings and the oxazolone ring are almost coplanar. The crystal structure is stabilized by weak intermolecular C—H...O hydrogen bonds.

Synthesis and crystal structure of two lanthanide coordination compounds of 4-(quinolin-8-yloxy)butanoic acid

Two lanthanide coordination compounds, [La(QYBA)3H2O]2 · 2H2O (1) and [Eu(QYBA)3(phen)]2 · 2H2O (2), have been synthesized and characterized structurally by X-ray diffraction, where QYBA = 4-(quinolin-8-yloxy)butanoic acid and phen = 1,10-phenanthroline. Their solid-state structures have been characterized by elemental analysis and IR spectroscopy. Both form a dimeric molecular structure through bridging oxygen atoms of carboxylate groups and both are nine-coordinate. Adjacent dimers in 1 are interlinked by QYBA into an infinite chain structure, while the dimers in 2 are interlinked by hydrogen bonds and π–π stacking interactions into a two-dimensional network.

4-{[(1,3-Benzothia­zolium-2-yl)hydra­zono](phen­yl)meth­yl}-3-methyl-1-phenyl-1H-pyrazol-5-olate monohydrate

The title compound, C24H19N5OS·H2O, was synthesized by the reaction of 4-benzoyl-3-methyl-1-phenylpyrazol-5-one and 2-hydrazino-1,3-benzothiazole. Proton transfer leads to the formation of a zwitterionic structure and the molecule exists in the enolate form. The pyrazolone ring makes dihedral angles of 35.4 (3), 69.7 (3) and 40.1 (3)° with the 1-phenyl, indirectly bound phenyl and benzothiazole ring systems, respectively. The molecules are linked into one-dimensional chains by a combination of N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds.

Synthesis and Structure of the Potassium Salt with Monodeprotonated 1,2,3-Tri(ethoxycarbonylpropyl)- p-t-butylcalix(6)arene

Alkylation of p-t-butylcalix[6]arene with ethyl 4-bromobutanoate in the presence of K2CO3 results in a potassium salt of the monodeprotonated 1,2,3-tri(ethoxycarbonylpropyl)-p-t-butylcalix[6]arene in high yield. X-Ray crystallographic analysis shows that this compound exists as a double partial cone conformation. The potassium ion is positioned near the centre of the cavity of the macrocycle and binds to four phenolic oxygens. Close contacts between the potassium ion and phenyl rings observed in this compound are indicative of the presence of the cation–π interaction. The molecules are connected via intermolecular K+···O interactions into infinite chains.

(2E,5E)-2,5-Bis(3,4,5-trimethoxy-benzyl-idene)cyclo-penta-none.

The title compound, C25H28O7, was prepared by the base-catalysed reaction of 3,4,5-trimethoxybenzaldehyde with cyclopentanone. The molecule has crystallographic twofold rotation symmetry and adopts an E-configuration about the central olefinic bonds. The two benzene rings and the central cyclopentanone ring are almost coplanar [dihedral angle = 4.7 (2)°].

The synthesis, crystal structure and enhanced blue fluorescence emission of novel antipyrine derivatives

Four new antipyrine derivatives were synthesized and characterized by elemental analysis, FT-IR, (1)H NMR, (13)C NMR spectroscopy, and a representative compound 1b was confirmed based on the X-ray crystallographic analysis. The antipyrine-phenylboronic acid 1b crystallizes in the monoclinic space group P2(1)/c, and displays an E configuration about the CN double bond. The absorption and fluorescence spectra of these compounds were investigated. Replacement of a six-membered phenyl group with a five-membered thienyl unit in the antipyrine derivatives resulted in a bathochromic shift approximately 21 nm, while the bithienyl system caused a strong bathochromic effect of 53 nm relative to the substituted phenyl groups. The bithienyl-antipyrine hybrid 1c displayed a turn-on fluorescence response to water, acetic acid (HOAc) and sulfuric acid (H(2)SO(4)) in ethanol solution, but no fluorescence response toward alkali. Whereas the free compound was very weakly fluorescent in ethanol, the addition of water, HOAc and H(2)SO(4) leads to an appearance of strong blue fluorescence and a dramatic increase of emission intensity.

(2E,6E)-2,6-Difurfurylidenecyclo-hexa-none.

The complete molecule of the title compound, C16H14O3, is generated by crystallographic mirror symmetry, with two C atoms and one O atom lying on the mirror plane. The molecule adopts an E configuration about the C=C bond and the dihedral angle between the furan rings is 16.1 (2)°.