[Co(en)3]2(Zr2F12)(ZrF6H2O)·H2O的合成、 结构及表面光电压性质

采用常温晶化法合成了1个新的金属配合物与氟化锆的复合物[Co(en)3]2(Zr2F12)(ZrF6H2O)·H2O(1), 并对其单晶结构进行了解析. 该化合物属单斜晶系, C2/c 空间群, a=3.06110(17) nm, b=0.877680(5) nm, c=1.50811(9) nm, β=118.897(4)°, V =3.547(4) nm3, Z=8. 该化合物由双核氟化锆阴离子簇 [Zr2F12]4-和单核氟化锆阴离子簇 [ZrF6H2O]2-与钴胺配合物阳离子 [Co(en)3]3+ 及水分子组成, 氟化锆与钴胺配合物之间存在大量的氢键. 该化合物的表面光电压谱在339 nm处出现了光电信号. 这种特殊的光电现象有可能归因于该化合物的钴胺配合物阳离子与氟化锆阴离子簇之间存在的协同作用.     

非水体系中大孔交联酰胺基树脂的吸附热力学

合成了大孔交联聚（N-甲基-N-对乙烯基苄基乙酰胺）树脂,测定了树脂对环己烷溶液中苯酚的吸附等温线,根据热力学函数关系计算了等量吸附焓、吉布斯吸附自由能和吸附熵,推测吸附过程为氢键吸附.同时,通过比较树脂对环己烷溶液中苯酚和邻硝基苯酚的吸附性能的差别,进一步论证了大孔交联聚（N-甲基-N-对乙烯基苄基乙酰胺）树脂对非水体系中酚类物质的吸附是基于氢键作用的机理.     

Novel complexes of zirconium and uranium derived from bifunctional azodyes donor ligands containing hydrogen bonds

Novel complexes of zirconium(IV) and uranium(II) with selective azodyes containing nitrogen and oxygen donor ligands have been prepared and characterized by elemental analysis, ¹H NMR and electronic spectral techniques. The important bands in the IR spectra and main ¹H NMR signals are assigned and discussed in relation to the proposed molecular structure of the complexes. The IR data of the azodye ligands suggested a bidentate binding involving azodye nitrogen and C–O/OH oxygen atom of enolic group. They also showed the presence of Cl/OAc coordinating with the metal ion. The prepared complexes of Zr(IV) fall into four types. In the stoichiometric formulae of (1:1), the chelate rings are six-membered/five coordinate; whereas in the (1:2) they are six-membered/six coordinate and all of the complexes possess non-electrolytic properties. The UO₂(II) complex, in the mean time, possesses a planar hexagonal structure with nitrogen and oxygen atoms in the axial position. The stretching vibrations and force constant interactions of the uranyl complexes have been determined and from which the U–O bond distances are calculated. These bond distances as well as the effect of Hamett’s constant are also, in turn, calculated and discussed.     

Colorimetric recognition of melamine in milk using novel pincer zinc complex stabilized gold nanoparticles

A convenient colorimetric approach for visual detection of melamine in raw milk was realized by using gold nanoparticles (AuNPs) stabilized by an unsymmetrical terpyridyl zinc complex with a thymine fragment at one terminal and a quaternary ammonium salt at the other. Even without pre-addition of melamine or relative additives, obvious color change from red to blue was observed by naked eye in the presence of trace amount of melamine, which was attributed to the alternation of aggregation state of AuNPs caused by the selective binding between the thymine fragment and melamine via triple hydrogen-bonding interactions. Remarkably, the detection limit for melamine was as low as 2.4 ppb, providing a highly sensitive and efficient approach for the visual detection of melamine.     

A spectrochemometric approach to tautomerism and hydrogen-bonding in 3-acyltetronic acids

3-Acyltetronic acids bearing different 3- and 5-substituents have been examined focussing on tautomerism and inter- and intramolecular hydrogen-bonding properties of these β,β′-tricarbonyl compounds in solution as well as in the solid state. Spectroscopic methods like NMR, IR, Raman-spectroscopy as well as X-ray diffractometry and MAS-NMR for the solid state have been applied. In a solution of CDCl₃, the acids exist as cis/trans pair both involving the 3-acyl group in a ratio 60/40. The pair also involving the carbonyl group at C-4 is tautomeric and the most abundant, whereas the other isomer only shows one form with an exo-cyclic double bond. NMR and IR measurements are in agreement. In the solid state, only one of the four possible tautomers is found. DFT-calculations on the B3LYP/6-31G** level helped to verify the assignment of the IR- and NMR-spectra and yielded an estimation of the relative thermodynamic stabilities of the tautomers of several 3-acyltetronic acids. Low temperature NMR experiments gave an insight into the equilibria. Deuterium isotope effects on the ¹³C NMR chemical shifts have been observed for 5,5-dimethyl 3-pivaloyltetronic acid at low temperature in order to examine the fast internal equilibria.     

Synthesis and photo DNA-damaging activities of fluoroquinolone analogues

Fluoroquinolone (FLQ) analogues were synthesized and their DNA photocleaving abilities were assayed. The photo-bioactivities of the fluoroquinolones were dependent on the carbonyl moieties attached to quinolone ring.     

Substituted phenylarsonic acids; structures and spectroscopy

Full NMR and ESI-MS spectra, and differential scanning calorimeter data are presented for 15 substituted phenylarsonic acids, including two new fluoro-substituted examples. X-ray crystal structure determinations of five examples (phenylarsonic acid and the 4-fluoro-, 4-fluoro-3-nitro-, 3-amino-4-hydroxy- and 3-amino-4-methoxy-substituted derivatives) were determined and the H-bonding crystal-packing patterns analysed.     

3D Solid-State Network from Hierarchical Supramolecular Self-Assembly of Transition Metal Complexes of Pyridine Based Ligand

Abstract  The crystal structures of [Cu(py)₄(ClO₄)](ClO₄) (1), [V(pic)₂(OH)](NO₃)₂ · H₂O (2) and [Ni(H₂O)₆][Ni(dpa)₂] · 2H₂O (3) [py = Pyridine, picH = Pyridine-2-carboxylic acid, dpaH₂ = Pyridine-2,6-dicarboxylic acid] was determined by single-crystal X-ray diffraction techniques. Solid-state structural analysis shows that all these complexes from extensive 3D network structure via supramolecular self-assembly. The crystal structures are stabilized by extended hydrogen bonding interactions. The complex 2 forms orange V₂O₅ micro spheroids when heated at ~400 °C for 6 h. Graphical Abstract  Hierarchical supramolecular self-assembly of transition metal complexes of pyridine based ligands in crystal. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Molecular co-crystals of carboxylic acids, part 29. The effect of competitive interactions on adduct formation involving 2-aminopyrimidine: the crystal structure of the 1∶1 adduct of 2-aminopyrimidine with indole-2-carboxylic acid

The crystal structure of the 1∶1 adduct of 2-aminopyrimidine with indole-2-carboxylic acid has been determined by single crystal X-ray diffraction, revealing a novel interactive mode. The utility of 2-aminopyrimidine in formation of stable hydrogen-bonded networks with carboxylic acids is discussed and the modes of interaction are reviewed. Part 28.,Aust. J. Chem., 1997, (submitted).     

Asymmetric Michael addition of α-nitro-ketones using catalytic peptides

Peptide-based catalysts have been developed that promote the asymmetric Michael addition of nitroalkanes. The most effective peptides contain a β-turn structural element as well as a basic histidine and an arylsulfonamide-protected arginine. Excellent yields with enantioselectivities of up to 74% ee have been observed.