ACE applied to the quantitative characterization of benzo‐18‐crown‐6‐ether binding with alkali metal ions in a methanol–water solvent system

ACE was applied to the quantitative evaluation of noncovalent binding interactions between benzo‐18‐crown‐6‐ether (B18C6) and several alkali metal ions, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺, in a mixed binary solvent system, methanol–water (50/50 v/v). The apparent binding (stability) constants (K_b) of B18C6–alkali metal ion complexes in the hydro‐organic medium above were determined from the dependence of the effective electrophoretic mobility of B18C6 on the concentration of alkali metal ions in the BGE using a nonlinear regression analysis. Before regression analysis, the mobilities measured by ACE at ambient temperature and variable ionic strength of the BGE were corrected by a new procedure to the reference temperature, 25°C, and the constant ionic strength, 10 mM . In the 50% v/v methanol–water solvent system, like in pure methanol, B18C6 formed the strongest complex with potassium ion (log K_b=2.89±0.17), the weakest complex with cesium ion (log K_b=2.04±0.20), and no complexation was observed between B18C6 and the lithium ion. In the mixed methanol–water solvent system, the binding constants of the complexes above were found to be about two orders lower than in methanol and about one order higher than in water.     

Solvent extraction of univalent and bivalent metal picrates with 1,2-bis[2-(2-methoxyethoxy)ethoxy] benzene (noncyclic crown ether) into CHCl3

The overall extraction equilibrium constants, K_ex, of 1:1:m complexes of 1,2-bis[2-(2-methoxyethoxy)ethoxyjbenzene (AC · B18C6) with uni- and bivalent metal picrates, MA _m were determined at 25°C between CHCl₃ and water, and thereby the ion-pair complex-formation constants,K _MLA,o, of AC · B18C6 with the univalent metal picrates in CHCl₃ were calculated. The AC · B18C6 is an open-chain analog of benzo-18-crown-6 (B18C6). The equilibrium constants of AC · B18C6 were compared with those of B18C6. K_ex sequences of AC · B18C6 for uni- and bivalent metals are Tl⁺ > K⁺ > Rb⁺ > Cs⁺ > Na⁺ > Li⁺ and Pb²⁺ > Ba²⁺ > Sr²⁺, respectively. The same extraction-selectivity was observed for B18C6, but the extractability of AC · B18C6 for the same cation is much lower than that of B18C6; the extraction selectivity of AC · B18C6 for alkali metals is lower than that of B18C6. TheK _MLA,o sequence of AC · B18C6 is K⁺ > Rb⁺ > Tl⁺ > Cs⁺ Na⁺, which is consistent with that of B18C6. ButK _MLA,o of AC · B18C6 is much smaller than the correspondingK _MLA,o of B18C6; the selectivity of AC · B18C6 among alkali metal picrates in CHCl₃ is lower than that of BI8C6. This reflects the difference in the structures between AC · B18C6 (acyclic and flexible) and B18C6 (cyclic and rigid).     

Crystal Structures of Ln（NO3）3（Ln=La,Yb）Complexes with 12—crown—4

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｓｏｆＬｎ（ＮＯ_３）_３（Ｌｎ＝Ｌａ，Ｙｂ）Ｃｏｍｐｌｅｘｅｓｗｉｔｈ１２－ｃｒｏｗｎ－４ＭａｏＪｉａｎｇ－Ｇａｏ；ＪｉｎＺｈｏｎｇ－Ｓｈｅｎｇ；ＹｕＦｅｎｇ－Ｌａｎ（ＬａｂｏｒａｔｏｒｙｏｆＲａｒｅＥａｒｔｈＣｈｅｍ...     

Solvent extraction of silver picrate by 3m-crown-m ethers (m = 5, 6) and its mono-benzo-derivative from water into benzene or chloroform: elucidation of an extraction equilibrium using component equilibrium constants

Ion-pair formation constant (K_AgPic in mol⁻¹ dm³) of silver picrate (AgPic), those (K_AgLPic) of its ion-pair complexes (AgLPic) with crown ethers (L) and complex formation constants (K_AgL) of Ag⁺ with L (15-crown-5 ether (15C5) and benzo-15C5) in water (w) were determined potentiometrically at 25 °C. Compounds used as L were 18-crown-6 ether (18C6), its benzo-derivative (B18C6) and the two 15C5 derivatives. Extraction constants (K_ex in mol⁻¹ dm³) of AgPic with L (15C5, 18C6, B18C6) from acidic w-phases into either C₆H₆ or CHCl₃ were recalculated from K_AgPic, K_AgL, K_AgLPic and data opened in previous papers. Thus obtained K_ex was divided into five component equilibrium constants containing K_AgL and K_AgLPic anew. Then, contributions of the component constants, K_AgL, K_AgLPic and distribution constants of AgLPic between the w- and C₆H₆-phases, to K_ex were discussed and compared with corresponding extraction systems of NaPic and KPic with18C6.     

Photoinduced recoordination in the complexes of bis-aza-18-crown-6-containing dibenzylidenecyclobutanone with alkali and alkaline-earth metal cations

Complexation with strong competitors (i.e., Ba²⁺, Ca²⁺, and K⁺) shortens the length of the chromophore in bis-aza-18-crown-6-containing dienones of 2,4-dibenzylenecyclo-butanone series due to the weakening of π–LP conjugation as well as disruption of the quinonoid structure in the ground state of the dye (LP is the lone electron pair of the crown nitrogen atom). In the excited state, recoordination of metal cations in the crown cavity takes place. The complexation as well as the newly discovered photorecoordination in these metal complexes may be used to control the chromophore properties of the samples.     

Crystal structures of the complexes of rare earth picrates with N, N, N'''', N''''-tetraphenyl-3, 6-dioxaoctanediamide

The complexes of rare earth picrate with N,N,N',N'-tetraphenyl-3,6-dioxaoctanediamide(TDD),Eu(picc(TDD)] 2CH3CN and [ Y(pic)3(TDD)],have been synthesized.The crystal structures reveal that TDD at is as n tetradentate ligand,forming a ring-like coordination structure with its oxygen atoms together with one oxygen atom of the bidentate pterate In the Eu(Ⅲ) complex,the europium ion with a larger ionic radius lies out of the ring,while in the Y(Ⅲ) complex,the yttrium ion with a smaller ionic radius enters the cavity of the ligand.The structures of the complexes are greatly affected by the ionic radii due to participation of the picrates in coordination.     

Synthesis of tripodal aza crown ether calix[4]arenes and their supramolecular chemistry with transition-, alkali metal ions and anions

Tripodal aza crown ether calix[4]arenes, 5a, 5b, 6a and 6b, have been synthesized. The structure of protonated 5a was elucidated by X-ray crystallography to be a self-threaded rotaxane. Complexation studies of 5a and 5b towards anions using Na⁺ as countercation were carried out by ¹H NMR titration in dimethylsulfoxide-d₆ and the mixture of chloroform-d and methanol-d₄, respectively. Ligands 5a and 5b were able to form 1:1 complexes with Br⁻, I⁻ and NO₃⁻ and the complexation stability varied as follows: NO₃⁻>I⁻>Br⁻. The effect of countercation on anion complexation was also investigated. The results showed that the association constants of 5a towards Br⁻ in the presence of various cations varied as K⁺>Bu₄N⁺>Na⁺. The enhancement in anion complexation ability of 5a may result from the rearrangement of the tripodal ammonium unit in the presence of K⁺. The neutral forms, 6a and 6b, were able to form complexes with transition metal ions such as Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺. The stability of the complexes followed the sequence: Ni²⁺2+Cu²⁺Zn²⁺. Compounds 6a and 6b may, therefore, potentially be used as either transition metal ion or anion receptors that can be controlled by pH of the solution.     

Crystal structure of the 1 : 1 : 6 complex between 18-crown-6, hydroquinone and water

Hydroquinone forms a 1 : 1 : 6 complex with 18-crown-6 and water. Crystals of this complex are monoclinic, space groupP2₁/a witha = 14.289(1),b = 7.972(1),c = 11.596(1) Å, = 97.72(1)°,Z = 2,D _c = 1.22 g cm^–3. The hydroquinone and crown ether molecules lie on centres of symmetry with the crown in theD _3d conformation. The water molecules act as a bridge between hydroquinone and the crown ether. The structure consists of molecules linked by a 3-dimensional network of hydrogen bonds: the hydroquinone and two water molecules lie roughly in the (001) plane; the crown ether and four water molecules form bipyramidal structures which are stacked in layers alternating with the previous planes.     

A novel covalent functionalisation of poly (styrene-alt-maleic anhydride) with 4-amino benzo-9-crown-3 ether

The grafting of 4-amino benzo-9-crown-3 ether to poly (styrene-alt-maleic anhydride) has been described. The covalent grafting of crown ether has led to a considerable increase in the solubility of polymer in organic solvents such as dimethyl sulphoxide, dimethylformamide and tetrahydrofuran. The highest solubility was attained in DMF and DMSO. The covalently bonded 4-benzo-9-crown-3 ether allowed the hosting of Li⁺. The covalently grafted crown ether to polymer was identified by infrared spectroscopy and thermogravimetric analysis methods.     

以2-苯氧乙基为氮支链的[18]和[15]环系氮支套索冠醚的合成及其络合性能

以2-苯氧乙醇为起始剂, 合成了两种新型氮支套索冠醚: N-(2-苯氧乙基)单氮杂-18-冠-6 (18CE)与N-(2-苯氧乙基)单氮杂-15-冠-5 (15CE). 通过红外光谱、核磁共振氢谱和紫外光谱表征了新冠醚及其中间体的结构. 用电导滴定法研究了两冠醚与Na^＋, K^＋, Ag^＋, NH^4＋, Ni^2＋, Cu^2＋, Pb^2＋和Co^2＋在25 ℃的配位作用, 计算了1∶1配合物的稳定常数. 实验结果表明, 由于N-(2-苯氧乙基)引入氮杂冠醚环和参与配位, 18CE和15CE配合物的稳定常数分别比单氮杂-18-冠-6, N-(2-羟基乙基)单氮杂-18-冠-6, N-(2-甲氧基乙基)单氮杂-18-冠-6和单氮杂-15-冠-5, N-(2-甲氧乙基)单氮杂-15-冠-5, N-(2-甲氧乙基)单氮杂-15-冠-5的对应配合物明显提高. 配合物的稳定常数和紫外光谱皆提供了支链的苯氧基参与配位的信息.     

DFT study of the carbon‐ and nitrogen‐pivot lariat crown ethers and their complexes with alkali metal cations: Na+, K+

In this work, a quantum mechanical research of five lariat crown ethers(LCEs), 2‐methoxy‐15‐crown‐5( A ), N‐methoxy‐4‐aza‐15‐crown‐5( B ), N‐methoxy‐4‐aza‐18‐crown‐6( C ), N‐methoxyethyl‐4‐aza‐18‐crown‐6( D ), N,N′‐bis(2‐metho xyethyl)‐4,13‐diaza‐18‐crown‐6( E ), which are based on either 15‐crown‐5 or 18‐crown‐6 frameworks and contain various pendant arms extending from either carbon or nitrogen atoms on the crown frameworks, had been done using density functional theory with B3LYP/6‐31G* method to obtain the electronic and geometrical structures of the LCEs and their complexes with alkali metal ions: Na⁺ and K⁺. The nucleophilicity of LCEs had been investigated by the Fukui functions. For complexes, the match between the cation and cavity size, the status of interaction between alkali metal ions and donor atoms in the LCEs, and the sidearm effect of the LCEs had been analyzed through the other calculated parameters, such as, highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, and energy gaps. In addition, the enthalpies of complexation reaction had been studied by the calculated thermodynamic data (298 K). The calculated results are all in a good agreement with the experimental data for the complexes. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009     

Crystal structures of the complexes of rare earth picrates with N, N, N′, N′-tetraphenyl-3, 6-dioxaoctanediamide

The complexes of rare earth picrate with N, N, N′, N′-tetraphenyl-3, 6-dioxaoctanediamide (TDD), [Eu(pic)₃(TDD)]-2CH₃CN and [Y(pic)₃(TDD)], have been synthesized. The crystal structures reveal that TDD acts as a tetradentate ligand, forming a ring-like coordination structure with its oxygen atoms together with one oxygen atom of the bidentate picrate. In the Eu (III) complex, the europium ion with a larger ionic radius lies out of the ring, while in the Y (III) complex, the yttrium ion with a smaller ionic radius enters the cavity of the ligand. The structures of the complexes are greatly affected by the ionic radii due to participation of the picrates in coordination. Project supported by the National Natural Science Foundation of China, the Doctoral Foundation of the State Education Commission of China, and the Climb Plan Foundation of the State Science and Technology Commission of China.     

[Na(DB18C6)(CH3CN)]2W6O19·(CH3CN)2的合成、晶体结构及谱学表征

A super-molecular complex, [Na(DB18C6)(CH₃CN)]₂W₆O₁₉·(CH₃CN)₂, was obtained by solvothermal reaction and characterized by IR , ¹H NMR, gumbc spectrum single crystal and X-ray diffraction. The compou- nd crystallizes in monoclinic space group P2₁/c with a=1.185 22(4) nm, b=2.091 51(8) nm, c=1.487 19(5) nm, β=117.467(2)° and Z=2. The complex contains four basic units: Na⁺, CH₃CN, DB18C6 and W₆O₁₉^2-. Sodium ions located in the cavity of dibenzo-18-crown-6 with 6 Na-O bonds and the crown ether-sodium ion complex is supported on the terminal oxygen atoms of the typical Lindqvist isopolyanion W₆O₁₉^2- via the coordinative interactions. W₆O₁₉^2- located between two DB18C6 and led to the formation of the “hamburger” structure. Two isolated CH₃CN are included in the complex. The whole title crystal is stabilized by van der waals force. CCDC: 292369.     

Study of complexation reactions between alkali and alkaline-earth metal cations with dibenzo-18-crown-6(DB18C6) in mixed nonaqueous solvents using the conductometry method

The complexation reactions between alkali and alkaline-earth metal cations with DB18C6 were studied in acetonitrile-methanol (AN-MeOH) and tetrahydrofuran-threechloromethane (THF-CHCl₃) binary mixtures at different temperatures using the conductometric method. The obtained results show that in most cases, the DB18C6 forms 1:1 complexes with these metal cations and the stability of the complexes is affected by the nature and composition of the mixed solvents. The stability order of complexes in AN-MeOH binary systems was found to be Na⁺ > Li⁺, and in the case of THF-CHCl₃ binary mixtures was Na⁺ > Ba²⁺ > Li⁺. An anomalous and interesting behavior was observed for the case of complexation of a K+ ion with DB18C6 in the AN-MeOH binary mixture and also for complexation of Mg²⁺ and Ca²⁺ cations with this ligand in pure THF and also in THF-CHCl₃ binary systems. The values of the thermodynamic parameters (ΔH _c ^o and ΔS _c ^o ) for complexation reactions obtained from the temperature dependence of the stability constants and the results show that the complexes are both enthalpy-and entropy-stabilized. The text was submitted by the authors in English.     

A study of the polarographic behaviour of meso-tetra(4-trimethylammoniumphenyl)porphine and its copper and magnesium complexes and its analytical applications

The investigation of the electrochemical reduction and the adsorption of meso-tetra(4-trimethylammoniumphenyl)porphine (T(4-TMAP)P) at a mercury electrode in alkaline solution shows that the overall reduction involves three two-electron steps, of which the first step is reversible and the latter two are irreversible. In addition, T(4-TMAP)P and its metal complexes of Cu(II) and Mg(II) can be strongly adsorbed on the surface of a mercury electrode. The adsorption phenomena have been utilized as a preconcentration step for the determination of trace amounts of the two ions by single sweep polarography. For copper, the detection limit is 1 × 10^–8 mol dm^–3, for magnesium, 1 × 10^–7 mol dm^–3, the latter being limited by the reagent blank. The proposed method was applied to the determination of Cu and Mg in various types of samples (chemicals, hair and liver tissues) with satisfactory results.     

Phosphorus-containing podands. 6. Calorimetric study of complexation of 1,17-bis (diphenylphosphinyl)-3,6,9,12,15-pentaoxaheptadecane with alkali and alkaline-earth metal salts in acetonitrile

1, 17-bis-(Diphenylphosphinyl-3, 6, 9, 12, 15-pentaoxaheptadecane in MeCN forms complexes of 11 and 12 composition (ML) with alkali and alkaline-earth metal salts, complexes of 11 and 21 composition were found for Li salts. The BaL²⁺ complex is the most stable complex, and the complexes NH₄L⁺ and CaL2+ are the least stable. The selectivity for Li is significantly higher for the podand studied than for crown ethers.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 575–581, March, 1991.     

Synthesis and structure of supramolecular complexes between 1-alkynyl(phenyl)(tetrafluoroborato)-λ-iodanes and 18-crown-6

Slow evaporation of a solution of 1-decynyl(phenyl)(tetrafluoroborato)-λ³-iodane and 18-crown-6 in dichloromethane-diethyl ether-hexane gave a supramolecular 1:1 complex, while 3,3-dimethyl-1-butynyl- and phenylethynyl(phenyl)(tetrafluoroborato)-λ³-iodanes afforded 2:1 complexes. Complexation with 18-crown-6 increased the thermal stability of the phenylethynyl-λ³-iodane. Solid state and solution structures of these complexes were examined by single crystal X-ray analyses, ¹H and ¹³C NMR spectra, and cold-spray ionization MS. Binding constants were measured by ¹H NMR titrations.     

Conductance study of ammonium complexes with several crown ethers and cryptands in nitrobenzene,acetonitrile and dimethylformamide solutions

The formation of ammonium complexes with several crown ethers and cryptands in nitrobenzene, acetonitrile and dimethylformamide solutions was investigated by conductometry at 25°C. Stability constants of the resulting 1:1 complexes sere determined from the molar conductance-mole ratio data and found to vary in the order DC18C6>18C6>DB30C10>DB21C7>DB24C8>DB18C6>15C5>B15C5>12C4, in the case of crown complexes, and in the order C222>C221>C211>C22>C21 for the ammonium cryptates. The stabilities of the complexes varied inversely with the Gutmann donicity of the solvents. Influences of the number of members in the macrocycle, nature of the substituents in the polyether ring, cavity size and dimensionality, conformations of the free and complexed ligands and number of N⁺–H bonds available for hydrogen bonding are discussed.     

Magnetic circular dichroism of phthalocyanine (m=mg, zn) and tetraazaporphyrin (m=mg, zn, ni) metal complexes. A computational study based on time-dependent density functional theory

We present here simulated magnetic circular dichroism (MCD) spectra of MTAP (M=Mg, Ni, Zn) and MPc (M=Mg, Zn) where TAP=tetraazaporphyrin and Pc=phthalocyanine. The study is based on magnetically perturbed time-dependent density functional theory (MP-TDDFT) and a newly implemented method for the calculation of A and B terms from the theory of MCD. It follows from our investigation that the MCD spectrum for the MTAP and MPc systems in the Q-band region consists of a single positive A term augmented by a positive B term, in agreement with experiment where available. The Q band can be fully characterized in terms of the 2a1u-->2eg one-electron excitation. For the aza systems MgTAP and ZnTAP, the simulated MCD spectra in the Soret region are dominated by the two one-electron excitations 2a2u-->2eg and 1a2u-->2eg and has the appearance of a positive A term (with values between 1.33-1.55, depending on the MTAP system) made asymmetric by a negative B term, in good agreement with experiment. We find, in agreement with all available experimental findings on MPc (M=Mg, Zn) type systems, that the MCD spectra in the Soret region are dominated by two transitions with positive A/ D-term values and two negative B/ D-term values. The major contribution to the two transitions comes from the 2a2u-->2eg and 1a2u-->2eg one-electron excitations. It appears that the ratio of A/ B for the term parameters is underestimated by theory.     

一维链状冠醚配合物[K(B18-C-6)]_2[M(SCN)_4](M=Pd,Pt)的合成与结构

合成了苯并18-冠-6（B18-C-6）与K_2[Pd(SCN)_4]生成的配合物[K（B18-C-6 ）]_(12) [Pd(SCN)_4] (1), [K(B18-C-6)]_2[Pt(SCN)_4] (2)和[K(B18-C-6)]_2 [Pt(SCN)_4]·C_2H_4Cl_2 (3),并通过元素分析、红外光谱、单晶X射线衍射进行 了表征。1和2为单斜晶系,空间群P2_l/n,晶体学数据：1, a = 1.00970(17) nm, b = 1.3157(2) nm, c = 1.7303(3) nm, β = 94.841(2)°, V = 2.2852(7) nm~3, Z = 2, F(000) = 1136, R_1 = 0.0257。3为三斜晶系,空间群P1,晶体学 数据：a = 0.95914(18) nm, b = 1.2137(2) nm, c = 2313(2) nm, α = 63.693 (2)°, β = 76.293(2)°, γ-1.2406(4) n~3, Z = 1 F(000)618,R_1 = 0.0366 。在固态,三个配合物相邻的两个[K（B18-C-6）]~+基团通过冠醚氧化原子与钾的 子的相边接而形成一维链状结构。