稀土硫氰酸盐与N-对氯苯基氮杂15-冠-5配合物的合成及晶体结构

合成了12种稀土金属硫氰酸盐与N-对氯苯基氮杂15-冠-5的固体配合物,进行了元素分析和电导、红外光谱、电子光谱测定及热重-差热分析,并对Sm(SCN)₃·L作了X射线单晶结构分析,结果表明:Sm(Ⅲ)离子与冠醚上的5个杂原子及3个硫氰酸根上的氮原子配位,配位数为8.     

Synthesis and Crystal Structure of Cu( Ⅱ ) Adduct with N-(4-Chlorophenyl)aza 15-Crown-5

The title compound C18 H25 NC4ClBr2Cu crystallizes in space group P 1 with a = 1.0105(2)nm b=1.0821(1) nm, c=1. 1007(2) nm, a=80. 00(1)°,β=80. 26(1)° γ=77. 83(1)°. Z=2, D = 1. 831 g/cm3, μ=62. 658 cm-1(Mok(?)). The final refinement converged to R=0. 031 for 2547 independent observed reflections. The complex molecule consists of two cationic moieties (HL)+ and an anion which appears as a bromide-bridged copper dimer (Cu2Br6)2-. This structural characterization seems to be rare in metal complexes with crown-ether.     

Synthesis, structure and properties of novel N-thiophosphorylated derivatives of 1,3-dihydro-2H-benzimidazol-2-imine and imidazolidine-2-imine

The reaction of bis-thiourea o-C₆H₄[NHC(S)NHP(S)(Oi-Pr)₂]₂ (1) with iodine, KOH and ClCH₂C(O)OCH₃ leads to O,O′-diisopropyl-1,3-dihydro-2H-benzimidazol-2-ylideneamidothiophosphate (2) formation. The complex of the potassium salt of compound 2 with 18-crown-6, having the composition [K(18-crown-6)L], has been synthesized. Bis-thiourea [CH₂NHC(S)NHP(S)(Oi-Pr)₂]₂ (6) forms a stable potassium salt, which oxidation by iodine leads to a product of heterocyclization, O,O′-diisopropyl-(1-{[(diisopropoxyphosphorothio)amino]carbonothioyl}imidazolidine-2-ylidene)amidothiophosphate (8), in which one of the thiourea fragments is kept.     

Stability of crown-ether complexes with alkali-metal ions in ionic liquid-water mixed solvents

Stability constants of sodium and cesium ion complexes with 18-crown-6 (18C6) and dibenzo-18-crown-6 (DB18C6) in N-butyl-4-methyl-pyridinium tetrafluoroborate [BMP][BF₄] aqueous solutions were measured using the ²³Na and ¹³³Cs NMR technique at 23 °C. To the best of our knowledge, the estimated values of stability constants reported in this study are the first such values given for ionic liquid solutions. The cationic exchange between the free and complexed species is rapid, and only formation of the 1:1 complexes [M(18C6)]⁺ and [M(DB18C6)]⁺ (M = Na⁺, Cs⁺) were observed. The complex formation constants demonstrated a strong dependence on the [BMP][BF₄] concentration. For [M(18C6)]⁺, in solutions with a 0.33–0.70 mole fraction of water in [BMP][BF₄], lg K values are found to be more than one unit higher than the lg K values measured in pure aqueous solutions, although no information concerning the influence of [BMP][BF₄] on the complex formation selectivity could be observed. DB18C6 complexes revealed significantly lower stability under the same conditions. An extrapolation to zero water content gave the lg K = 2.42 for [Cs(18C6)]⁺ in [BMP][BF₄]. It was discovered that when added to water, [BMP][BF₄] increases the solubility of crown ethers and decreases the solubility of alkali metal nitrates. Complex formation with crown ethers enhances the solubility of alkali metal salts in [BMP][BF₄].     

Synthesis of a New pH-Dependent Ligand: Conformational and Complexation Studies

A new macrocyclic ligand, 3, which exhibits pH-induced conformational changes, has been prepared. This ligand consists of a crown ether derived from a trans-anti-trans 1,2,4,5-tetrasubstituted cyclohexane. Due to the stereochemistry of the substituents on the carbocyclic ring, two different low-energy conformations of the crown ether are possible. Ligand 3 has been studied in solution by ¹H NMR spectroscopy at different values of pH and temperature, showing that the conformation of the crown ether, and thus its complexing ability, is strongly pH-dependent. The solid-state structure of the ligand has been determined by X-ray diffraction.     

Novel crowned-porphyrin ligands. Synthesis and conformational studies

Three new macromolecules—a cryptand, a bis-macrocycle, and a tris-macrocycle—have been synthesized as chelating ligands for cation binding. They result from the surprisingly simple reaction of various bis-functionalized meso-aryl porphyrins with a diaza-crown ether coupled one to each other through either one or several urea linkage(s). Indeed, the latter induces some additional rigidity in comparison with the usual amide linkage found in such macromolecules. Various strategies are reported to optimize the yield of the reaction towards the formation of a cofacial singly-linked crown-porphyrin, which is the most promising ligand to stabilize large cations such as bismuth(III) as the angle between the two macrocycles can vary.     

An extended tetrathiafulvalene redox-ligand incorporating a thiophene spacer

An extended tetrathiafulvalene derivative incorporating a thiophene spacer and a fused crown-ether unit has been synthesized. This highly delocalized system exhibits remarkable electrochemical recognition properties for Na⁺ and Ba²⁺ as shown by cyclic voltammetry in methylene chloride. This result is attributed to the proximity between the guest metal cation and the positive charge of the oxidized ligand, which is located on the central conjugated thiophenic part.     

Schiff碱双冠醚和稀土硝酸盐配位行为的研究

迄今为止,研究稀土冠醚配合物所用的配体都是分子中含一个冠醚环的单冠醚化合物,配体中含有两个冠醚环的双冠醚稀土配合物还未见到报道。Handside于1982年报道了一系列结构式为右边所示的Schiff碱双冠醚。本文报道m=2,n=2的Schiff