叔丁基取代二苯并-18-冠-6的合成

以二甘醇和邻苯二酚为原料制得二苯并-18-冠-6;以多聚磷酸为催化剂和溶剂,将二苯并-18-冠-6与叔丁醇反应实现叔丁基化;利用正庚烷重结晶对叔丁基化反应产物进行纯化,得到4,4′-二叔丁基二苯并-18-冠-6和4,5′-二叔丁基二苯并-18-冠-6两种对称的二叔丁基二取代苯并冠醚产品.利用红外光谱和核磁共振谱表征了二叔丁基二取代苯并冠醚产物的结构。     

聚1,10—癸二酮二苯并—14—冠—4的合成

设计并合成了聚１，１０－癸二酮二苯并－１４－冠－４，改进了二苯并－１４－冠－４的合成，缩短了反应时间，收率从１０％提高到１７％，并开展了聚１，１０－癸二酮二苯并－１４－冠－４与ＰＶＣ共混用于碳膜Ｌｉ＾＋离子选择性电极研究。     

二环己基并18冠6的制备方法

二苯并-18－冠-6;二环己基并18冠6的制备方法     

(1S,6R)-1-羟基-6-(1,3-苯并二硫-2-氧)-3,5-环维生素D2的合成

以VD2为原料制备了1α，25－二羟基维生素D3的重要中间体（1S，6R）－1－羟基－6－（1，3－苯并二硫－2－氧）－3，5－环维生素D2。其中BDT（1，3－苯并二硫－2－氧）基团的引入有利于共轭三烯系统的保护。     

二苯并-18-冠-6-硝化产物异构体的分离及顺式化合物的结构测定

在改进的条件下,二苯并-18-冠-6硝化反应的产率达90％以上。提出一种分离二硝基二苯并-18-冠-6的顺、反异构体的方法。反应产物经元素分析和红外光谱鉴定,异角X射线衍射法测定了顺式二硝基二苯并-18-冠-6的晶体结构。晶体空间群为P2_1/n,α=15.95i(7),b=20.411(9),c=8.173(4),β=101.09(4)°,Z=4。结构用直接法解出,R=0.067。     

癸二酸-二苯并-18-冠-6共聚物的合成

脂肪族二元羧酸与二苯并 １８ 冠 ６在多聚磷酸中进行酰基化反应，可以制得酮型冠醚聚合物，二元酸的分子链长度会影响聚合反应的难易程度．对聚合反应条件进行优化控制，可以制得分子量高、成膜性能良好的癸二酸 二苯并 １８ 冠 ６共聚物．     

双冠醚的研究(Ⅶ)——Schiff碱型和仲胺型双(苯并-18-冠-6)的合成

4′-氨基苯并-18-冠-6分别与间-硝基苯甲醛、对-硝基苯甲醛、间-苯二甲醛及其取代物和对-苯二甲醛缩合制得6种新的Schiff碱型单冠醚和双冠醚。4′-甲酰基苯并-18-冠-6分别与4′-氨基苯并-15-冠-5、4′-氨基苯并-18-冠-6作用制得2个醚环大小相同和不同的Schiff碱型双(苯并冠醚)。这些双冠醚经硼氢化钠还原得到相应的6种新的仲按型双冠醚。     

吖啶基功能化二苯并-18-冠-6的合成

通过改变离去基团的活性、亲核试剂、溶剂的极性、离子性及反应温度等,对传统的U llm ann合成法进行了优化,将二苯并-18-冠-6进一步功能化,合成了未见文献报道的N,N′-二-(9-吖啶基)-4,4′-二氨基二苯并-18-冠-6,收率在87%以上。其结构经1H NMR,IR及元素分析表征。     

4,4′-二胺甲基联苯搭桥的二苯并-18-冠-6环状二聚体的合成

在高度稀释条件下 ,二酰氯 (1)与二氨基二苯并 18 冠 6 (2 )反应 ,以高收率生成大环二酰胺 (3) ,3在甲苯溶剂中用SMEAH[二 (2 甲氧乙氧基 )二氢化钠铝 ]还原得到目标化合物——— 4,4′ 二胺甲基联苯搭桥的二苯并 18 冠 6环状二聚体 (4 ) .在吡啶溶剂中 4与 [6 0 ]富勒烯有弱的π 电子给体 -受体相互作用 .     

二氨基二苯并-14-冠-4的合成与表征

二硝基二苯并冠醚;二氨基二苯并冠醚;二氨基二苯并-14-冠-4的合成与表征     

Experimental and theoretical study of the coordination of 1,2,4-triazolato, tetrazolato, and pentazolato ligands to the [K(18-crown-6)]+ fragment

Treatment of 3,5-diisopropyltriazole, 3,5-diphenyltriazole, 3,5-di-3-pyridyltriazole, phenyltetrazole, pyrrolidinyltetrazole, or tert-butyltetrazole with equimolar quantities of potassium hydride and 18-crown-6 in tetrahydrofuran at ambient temperature led to slow hydrogen evolution and formation of (3,5-diisopropyl-1,2,4-triazolato)(18-crown-6)potassium (88%), (3,5-diphenyl-1,2,4-triazolato)(tetrahydrofuran)(18-crown-6)potassium (87%), (3,5-di-3-pyridyl-1,2,4-triazolato)(18-crown-6)potassium (81%), (phenyltetrazolato)(18-crown-6)potassium (94%), (pyrrolidinyltetrazolato)(18-crown-6)potassium (90%), and (tert-butyltetrazolato)(18-crown-6)potassium (94%) as colorless crystalline solids. (1,2,4-Triazolato)(18-crown-6)potassium was isolated as a hemi-hydrate in 81% yield upon treatment of 1,2,4-triazole with potassium metal in tetrahydrofuran. The X-ray crystal structures of these new complexes were determined, and the solid-state structures consist of the nitrogen heterocycles bonded to the (18-crown-6)potassium cationic fragments with eta2-bonding interactions. In addition, (3,5-diphenyl-1,2,4-triazolato)(tetrahydrofuran)(18-crown-6)potassium has one coordinated tetrahydrofuran ligand on the same face as the 3,5-diphenyl-1,2,4-triazolato ligand, while (3,5-di-3-pyridyl-1,2,4-triazolato)(18-crown-6)potassium forms a polymeric solid through coordination of the distal 3-pyridyl nitrogen atoms to the potassium ion on the face opposite the 1,2,4-triazolato ligand. The solid-state structures of the new complexes show variable asymmetry in the potassium-nitrogen distances within the eta2-interactions and also show variable bending of the heterocyclic C2N3 and CN4 cores toward the best plane of the 18-crown-6 ligand oxygen atoms. Molecular orbital and natural bond order calculations were carried out at the B3LYP/6-311G(d,p) level of theory on the model complex, (phenyltetrazolato)(18-crown-6)potassium, and demonstrate that the asymmetric potassium-nitrogen distances and bending of the CN4 core toward the 18-crown-6 ligand are due to hydrogen bond-like interactions between filled nitrogen-based orbitals and carbon-hydrogen sigma orbitals on the 18-crown-6 ligands. Calculations carried out on the model pentazolato complex (pentazolato)(18-crown-6)potassium predict a structure in which the pentazolato ligand N5 core is bent by 45 degrees toward the best plane of the 18-crown-6 oxygen atoms. Such bending is induced by the formation of intramolecular nitrogen-hydrogen-carbon hydrogen bonds. Examination of the solid-state structures of the new complexes reveals many intramolecular and intermolecular nitrogen-hydrogen distances of < or =3.0 A which support the presence of nitrogen-hydrogen-carbon hydrogen bonds.     

Weak carbon-hydrogen-nitrogen interactions affect the heterocyclic ligand bonding modes in barium complexes containing eta2-tetrazolato and eta2-pentazolato ligands

Treatment of Ba[N(SiMe3)2]2(THF)2 with 2 equiv of dimethylaminotetrazole or diisopropylaminotetrazole and 1 equiv of 18-crown-6 afforded Ba[CN4(NMe2)]2(18-crown-6) (87%) and Ba[CN4(NiPr2)]2(18-crown-6) (79%) as colorless crystalline solids. Ba[CN4(NMe2)]2(18-crown-6) contains two 1,2-eta2-tetrazolato ligands and one eta6-18-crown-6 ligand. The molecular structure of Ba[CN4(NiPr2)]2(18-crown-6) is similar to that of Ba[CN4(NMe2)]2(18-crown-6), except that the tetrazolato ligands exhibit the isomeric 2,3-eta2-coordination mode and the tetrazolato ligand CN4 cores are bent significantly toward the 18-crown-6 ligands. Molecular orbital calculations were carried out on the model complexes Ba(azolate)2(18-crown-6) (azolate = 1,2-eta2-CHN4, 2,3-eta2-CHN4, and eta2-N5) and demonstrate that the ligand coordination modes are influenced by intramolecular interactions between filled nitrogen orbitals on the azolato ligands and empty C-H sigma* orbitals on the 18-crown-6 ligands.     

Conductance Study of the Thermodynamics of Tl+ ion Complexes with Different 18-Membered Crown Ethers in Binary Dimethylformamide-Acetonitrile Mixtures

A conductance study of the interactionbetween Tl⁺ ion and 18-crown-6 (18C6),dicyclohexano-18-crown-6 (DC18C6), benzo-18-crown-6(B18C6), diaza-18-crown-6 (DA18C6),dibenzyldiaza-18-crown-6 (DBzDA18C6) andhexaaza-18-crown-6 (HA18C6) indimethylformamide-acetonitrile mixtures was carriedout at various temperatures. The formation constantsof the resulting 1 : 1 complexes were determined fromthe molar conductance-mole ratio data and found tovary in the order HA18C6 > DA18C6 > DBzDA18C6 >18C6 > DC18C6 > B18C6. The enthalpy and entropy ofthe complexation reactions were determined from thetemperature dependence of the formation constants.     

Volume Changes on Complex Formation of 18-Crown-6 with Amino Acids in Aqueus Solutions

The densities of 18-crown-6-water and 18-crown-6-amino acid-water solutions at 298.15 K were determined. These values were used to estimate the partial molar volumes of 18-crown-6 in water and 0.15 M aqueous solutions of amino acids, as well as the volumes of transfer of 18-crown-6 from water to aqueous solutions of amino acids. The interaction of 18-crown-6 with amino acids involves H bonds and electrostatic forces. A conclusion was drawn that the nature and arrangement of side groups in amino acids affect their complex formation with the crown ether.     

A Polarographic Study on Some Complexes of Pb2+ and Cd2+ with Macrocyclic Polyethers (Crown Ethers)

Abstract

Complexation constants of Pb²⁺ and Cd²⁺ nitrates with five crown compounds (18-crown-6, dicyclohexyl-18-crown-6, benzo-15-crown-5, dibenzo-24-crown-8 and 12-crown-4), have been determined by d.c. and a.c. polarographic measurements in aqueous medium using 0.1 M HNO₃ as supporting electrolyte. The complexes of lead with 18-crown-6 and dicyclohexyl-18-crown-6 are very stable which may be attributed to the partially covalent bonds formed by this metal ion.     

Interactions of nitrosonium salts with crown ethers

Interactions of nitrosonium tetrafluoroborate and hexafluorophosphate with 18-crown-6, 15-crown-5, and 12-crown-4 in dichloromethane, acetonitrile, and nitromethane have been probed by a combination of proton magnetic resonance spectroscopy, infrared spectroscopy, and conductance measurements. The stoichiometrics of the crown ether-nitrosonium salt complexes were one mole of 18-crown-6 per mole of nitrosonium salt and two moles of 12-crown-4 per mole of nitrosonium salt in all solvents. For 15-crown-5, the one-to-one stoichiometry observed in acetonitrile and nitromethane changed to two moles of crown ether per mole of nitrosonium salt in dichloromethane. The nature of these complexes is discussed. Treatment of a solution of equimolar nitrosonium hexafluorophosphate and 18-crown-6 in dichloromethane with water produced hydronium hexafluorophosphate-18-crown-6 complex.     

A PGSE diffusion and electrophoretic NMR study of Cs+ and Na+ dynamics in aqueous crown ether systems

Multinuclear pulsed gradient spin-echo (PGSE) NMR diffusion and linewidth measurements were used to probe binding and transport in aqueous Na+-15-crown-5, Na+-18-crown-6, Cs+-15-crown-5 and Cs+-18-crown-6 systems. Since direct PGSE observation of many alkali cations is precluded by either low inherent sensitivity or rapid relaxation (or both), the feasibility of proton-detected electrophoretic NMR (ENMR) measurements to complement PGSE data was investigated. ENMR measurements were performed on aqueous Cs+-, Li+-, Na+-, K+-, and Rb+- 18-crown-6 systems. The data analysis is based on a two-site binding model and its corresponding association constants. Cs+ was found to bind considerably more tightly to 18-crown-6 (K=8 M-1) than to 15-crown-5 (K approximately 2 M-1), whereas Na+ had almost equal affinity (K approximately 4.5 M-1) for 15-crown-5 and 18-crown-6. The difficulties encountered in analysing the NMR parameters, methodological limitations and the implied need for more complicated binding models are discussed.     

Extraction of strontium from nitric acid solutions by selected crown ethers

The extraction of Sr from nitric acid solutions by the crown ethers, 12-crown-4, 15-crown-5, 18-crown-6 and DB 18-crown-6 dissolved in chloroform has been investigated. Sr is reasonably well extracted by 18-crown-6 compared to other crown ethers from different nitric acid solutions. The extraction is strongly dependent on the concentration of HNO₃ and nitrate salts. Preliminary studies indicate that¹³⁷Cs is also extracted to a limited extent by 18-crown-6 from nitrate medium. Stripping of Sr was achieved by an aqueous solution of low acidity, the crown ether being regenerated for subsequent extraction.     

2,4-dithiouracil: the reproducible H-bonded structural motifs in the complexes with 18-membered crown ethers

2,4-dithiouracil (DTU) forms in the crystals the H-bonded monohydrates of a 1:1:1 ratio with 18-crown-6 (18C6) 1, cis,syn,cis-isomer of dicyclohexano-18-crown-6 (DCH6A) 2, and benzo-18-crown-6 (B18C6) 3, while the anhydrous adduct with cis,anti,cis-isomer of dicyclohexano-18-crown-6 (DCH6B) 4 is of a 2:1 ratio. In 1-3 the components reproducibly alternate in the chains, while in 4 the chains are built of the alternative centrosymmetric dimers of 2,4-dithiouracil and the molecules of the cis,anti,cis-isomer of dicyclohexano-18-crown-6.