Environmental Effect of Macrocyclic Molecules on the Oxidation of Triethylamine by Ferricyanide Ion in Aqueous Solution

The effect of 18-crown-6 and kryptofix (2,2,1) on the oxidation of triethylamine byaqueous ferricyanide ion has been studied at pH 4, 7, and 9.The macrocycle retarded the normal oxidation process at all pH values,the effect depending on the macrocyclic ligand concentration Kryptofix (2,2,1) had a greater effect than 18-crown-6 at all pHvalues in this study. For 18-crown-6, retardation decreases in the order pH 9 > 4 > 7 while forkryptofix it follows the order pH 9 > 7 > 4.     

Recognition of Monohydrogen Anions of Geometrical and Positional Isomers of Dicarboxylic Acids Based on Polymeric Liquid Membranes Incorporating Polyamine Host

Macrocyclic lipophilic polyamines were applied as the sensory elements of polymeric liquid membrane electrodes. These hosts gain the anion receptor functionality upon protons uptake from the aqueous solutions. The electrodes studied were able to distinguish potentiometricaly isomers of monocharged and doublecharged forms of ethylene and benzene dicarboxylic acids. The selectivity of interaction between protonated hosts and anionic guests relays not only on the electrostatic interactions, but on hydrogen bounds formations as well. The influence of lipophilicity of protonated hosts on the potential response generation was discussed.     

大环二萜类化合物的研究(Ⅳ)——Isosarcophytol—A前体化合物的合成

Isosarcophytol-A(1)是1982年首次从澳大利亚软珊瑚(Nephthea brassica)中分离鉴定的西松烷型(Cembrane)大环二萜类化合物,其结构为6,10,14-三甲基-3-异丙基-3E,5E,9E,13E-环十四碳四烯-1-醇,是Sarcophytol—A(2)的异构体,但有关1的生物活性试验和全合成研究尚未见报道.我们在前文报道了以低价钛诱导的分子内二羰基偶联为环化方法,完成了天然大环二萜类化合物Cembrene—C的全合成和Sarcophytol—A(2)苄醚衍生物(3)的合成.本文报道以天然法呢醇4为起始原料,经区域选择性氧化、羟醛缩合等六步反应,合成了1的前体化合物11.合成路线如下:     

Stable silica gel-bound crown ethers. Selective separation of metal ions and a potential for separations of amine enantiomers

Silica gel-bound crown ethers and aza macrocycles have been synthesized with the attaching arm connected to the carbon framework of the macrocycles. The interactions of these bound macrocycles with cations are almost identical to those involving the analogous free macrocycles. This has allowed for predictable cation separation, concentration, and removal processes to be performed on a small scale. Quantum mechanical calculations and NMR measurements indicate that similarly bound chiral macrocycles will be capable of use in separating chiral organic amines.Dedicated to the memory of Professor James J. Christensen who died on 5 September 1987.     

Two new tetranuclear complexes of the macrocyclic oxamide [MCu3] (M = Cd, Mn, macrocyclic oxamide = 1,4,8,11-tetraazacyclotradecanne-2,3-dione): syntheses, spectra and magnetic properties

Two new tetranuclear complexes of macrocyclic oxamide [Cd(CuL)₃](NO₃)₂·2.5H₂O 1, [Mn(CuL)₃(OH)₂](ClO₄)₂·Mn(H₂O)₆·4.5H₂O 2 (L = 1,4,8,11-tatraazacyclotradecanne-2,3-dione) have been synthesized, structurally characterized and preliminary investigated by magnetic studies. The structures of the title complexes consist of a tetranuclear units MCu₃ (M = Cd, Mn), the packing diagram shows two-dimensional and three-dimensional system through intermolecular weak interactions. The temperature-dependent magnetic susceptibilities of complex 2 were analyzed by an approximate treatment leading to J = −33 cm⁻¹, g_Cu = 2.10, g_Mn = 1.95 indicating antiferromagnetic exchange between Cu(II) and Mn(II) ions.     

NMR and potentiometric determination of the high pK values and protonation sequence of dipyridino-hexaaza-28-crown-8 and its interactions with selenate,sulfate and nitrate ions in aqueous solution

The aqueous protonation and anion-binding SeO ₂ ^–/4 SO _2– ⁴ , and NO _– ³ ) constants of the macrocyclic polyamine ligand, dipyridino-hexaaza-28-crown-8(L), were measured in 0.1M KCl using a potentiometric titration technique. The protonation sequence of the aza groups of L was studied in D₂O from the chemical shifts of the nonlabile protons so as to find the charge distribution geometry as a function of pD. The study indicates that in 0.1M KC1 fully protonated L forms stable l: 1 complexes with SeO _2– ⁴ (logK=3.68) and SO _2– ⁴ (logK=3.55), but not with NO _– ³ (logK < l.5). All of the amine pK values were above 6.3, thus allowing the use of the protonated form of this ligand over a wide pH range.     

由水杨醇衍生的二苯并冠醚的合成和构型

将水杨醇在ＤＭＦ中与ＮａＨ和二甘醇或三某醇二对甲苯磺酸酯反，合成了２个新的二苯并冠醚（１和２），其结构由元素分析和波谱分析所表征，１ 射线衍射分析确定为反位构型，提出了合成反应的机理。     

The scandium(III) ion as a template for the synthesis of a hexaazaSchiff base macrocyclic ligand

Summary The condensation of 2,6-diacetylpyridine andm-phenylenediamine in the presence of scandium(III) perchlorate as a template agent affords a new 20-membered macrocyclic complex of formula ScL(ClO₄)₃·4H₂O, whereL is Me₄ bzo ₂ pyo ₂[20]octaene-N₆.

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Scandium(III) als Matrix für die Synthese eines makrocyclischen Hexaazaliganden

Zusammenfassung Die Kondensation von 2,6-Diacetylpyridin undm-Phenylendiamin in Gegenwart von Scandium(III)perchlorat als Matrix liefert einen neuen makrocyclischen Komplex der Zusammensetzung ScL(ClO₄)₃·4H₂O (L=Me₄ bzo ₂ pyo ₂[20]octaen-N₆).

     

Synthesis of two new crown ethers containing selenium and the complexation of one of them with silver and lead

Two new macrocyclic crown ethers containing one or two selenium donor atoms have been prepared. Diselena-18-crown-6 (2) was found to transport silver ions through a methylene chloride bulk membrane at about the same rate as the analogous dithia- (3) and diaza-18-crown-6 (4) compounds and transported lead ions about the same as dithia-18-crown-6 but better than diaza-18-crown-6.     

Structure-driven design and synthesis of chiral dioxocyclam derivatives

Based on an analysis of previously reported structures and a potential geometry fit with substrates, a new family of chiral dioxocyclam derivatives have been designed. The synthesis of those ligands was accomplished starting from l-proline and α-d-amino acids (converted to β-amino acids) with a key step of macrocyclization reaction of amino esters. All ligands were converted into neutral copper(II) complexes (amide groups underwent deprotonation of upon treatment of ligands with copper(II) acetate). The complexes exhibit the desired shape of their active surfaces, as proved by X-ray analysis.