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1.
The polyphosphide anions in ethylenediamine/2,2,2-crypt, ethylenediamine/18-crown-6 and ethylenediamine/db18-crown-6 solutions are isolated as K[K(2,2,2-crypt)]3(HP7)2 · en (1), [K(18-crown-6)]2HP7 (2) and [K(db18-crown-6)]2HP7 · toluene (3). The mono-protonation of the P7 cluster is observed in all three compounds. The (HP7)2− units are stabilized by naked potassium in 1 and complexing potassium in 2 and 3. The significant C-H?P hydrogen bonding interaction is observed in 3, which is responsible for the 3-D supramolecular structure. The 3-D supramolecular structure is also contributed by the η2-interaction between K+ and the phenyl. The 31P and 1H NMR spectra of 1-3 indicate that the polyphosphide anions are very fluxional in solution. 相似文献
2.
Reaction of the zwitterionic imidazolium salt [(CH2COOH)(CH2COO)im] with K2CO3 or BaO in the presence of 18-crown-6 affords the salts [(CH2COO)2im][K(18-crown-6)] and [(CH2COO)2im]2[Ba(18-crown-6)], respectively. Recrystallisation of these crown complexes from the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [emim][Tf2N], at a water interface, results in the formation of new salts in which the original anion is replaced by Tf2N−. Single crystal X-ray diffraction has been performed on two of the salts. Notably, the potassium structure containing 18-crown-6 and Tf2N− forms a linear chain coordination polymer that can be regarded as metal organic frameworks (MOFs). Moreover, this study provides insights into the separation of group I and II metal ions using crown ethers in combination with ionic liquids. 相似文献
3.
Reaction of LaCl3·7H2O containing small amounts of La(NO3)3·7H2O as an impurity with 12-crown-4 or 18-crown-6 in 3:1 CH3CN:CH3OH resulted in the isolation of the mixed anion complexes [LaCl2(NO3)(12-crown-4)]2, [La(NO3)(OH2)4(12-crown-4)]Cl2·CH3CN and [LaCl2(NO3)(18-crown-6)]. The nine-coordinate dimer, [LaCl2(NO3)(12-crown-4)]2, has all of the anions in the inner coordination sphere and La3+ has a capped square antiprismatic geometry. It crystallizes in the orthorhombic space group Pbca with (at −150 °C) a = 12.938(6), B = 15.704(3), C = 13.962(2) Å, and Dcalc = 2.08 g cm−3 for Z = 4. The second complex isolated from the same reaction, [La(NO3)(OH2)4(12-crown-4)]Cl2·CH3CN, has the bidentate nitrate anion in the inner coordination sphere but the two chloride anions are in a hydrogen bonded outer sphere. This complex is ten-coordinate 4A,6B-expanded dodecahedral and crystallizes in the monoclinic space group P21 with (at 20 °C) A = 7.651(2), B = 11.704(7), C = 11.608(4) Å, β = 95.11(2)°, and Dcalc = 1.80 g cm−3 for Z = 2. The 18-crown-6 complex, [LaCl2(NO3)(18-crown-6)], has all inner sphere anions and has ten-coordinate 4A,6B-expanded dodecahedral La3+ centers. It crystallizes in the orthorhombic space group Pbca with (at 20 °C) a = 14.122(7), B = 13.563(5), C = 19.311(9) Å, and Dcalc = 1.89 g cm−3 for Z = 8. 相似文献
4.
The reactions of cadmium halides with the 15-membered macrocyclic crown ethers, 15-crown-5 and benzo-15-crown-5, have been carried out and six new complexes have been isolated and structurally characterized. Metal to ligand stoichiometries of 1:1, 2:1, 3:1 and 3:2 have been observed with a variety of different formulations. Examples of charge separated ion pairs ([(NH4)(benzo-15-crown-5)2]2[Cd2I6]), halogen bridged monomers, dimers or polymers ([Cd(15-crown-5)(OHMe)(μ-Br)CdBr3], [Cd(15-crown-5)(μ-Br)2CdBr(μ-Br)]2(isolated from the same reaction mixture) and [(CdCl2)2CdCl2(15-crown-5)]n), and hydrogen bonded finite chains or polymers ([(Cd(OH2)2(15-crown-5)][CdI3(OH2)]2·2(15-crown-5)·2CH3CN and [CdI2(OH2)2(THF)]·benzo-15-crown-5) have been isolated. Three different types of 15-crown-5 coordination modes have been observed in these complexes. In-cavity coordination resulting in pentagonal bipyramidal geometries about Cd2+ was observed in [(CdCl2)2CdCl2(15-crown-5)]n, [Cd(15-crown-5)(OHMe)(μ-Br)CdBr3], and [Cd(OH2)2(15-crown-5)][CdI3(OH2)]2·2(15-crown-5)·2CH3CN, [Cd(15-crown-5)(μ-Br)2CdBr(μ-Br)]2 displays out-of-cavity coordination with one etheric donor distorted into an axial position of a distorted pentagonal bipyramid. The third coordination mode is secondary sphere coordination via hydrogen bonding which is observed for [Cd(OH2)2(15-crown-5)][CdI3(OH2)]2·2(15-crown-5)·2CH3CN. The good fit of Cd2+ within the cavity of 15-crown-5 results in shorter bonding contacts and a more narrow distribution in Cd---O values (2.273(7)-2.344(6) Å) than observed for cadmium halide complexes of 18-crown-6 (Cd---O = 2.69(1)–2.81(1) Å). 相似文献
5.
The effect of benzo-18-crown-6, a synthetic ionophore, on stomatal opening and its interaction with abscisic acid 总被引:3,自引:0,他引:3
C. H. RICHARDSON M. R. TRUTER J. N. WINGFIELD A. J. TRAVIS T. A. MANSFIELD R. G. JARVIS 《Plant, cell & environment》1979,2(4):325-327
Abstract. Treatment of tomato seedlings with 5 mM benzo-18-crown-6, a potassium ionophore, produced a reduction in transpiration of 40%. Treatments of epidermal strips of Commelina communis with ben-zo-18-crown-6 (1-l0mM) inhibited stomatal opening, and this effect was shown to be reversible. An antagonistic interaction between abscisic acid (10−7 M) and benzo-18-crown-6 (4 × 10−3 M) was also observed. 相似文献
6.
Ming WenMegumu Munakata Yusaku SuenagaTakayoshi Kuroda-Sowa Masahiko Maekawa 《Inorganica chimica acta》2002,332(1):18-24
Three silver(I) complexes of dibenzo-18-crown-6-ether (DB[18]C6), [Ag(DB[18]C6)(ClO4)](THF) (1), [Ag(DB[18]6)(CF3SO3)]2(acetone)2 (2) and [Ag(DB[18]C6)(CF3COO)]2(AgCF3COO)2 (3) have been synthesized in different solvents and characterized structurally. In each complex, silver ions prefer an octahedral coordination geometry and form close dinuclear complex with DB[18]C6 based on cation-π interaction in η2-fashion. In particular, the coordination unit involving σ bonding at an oxygen group and π-π bonding between two benzene rings is quite unique. 相似文献
7.
A highly anionic cyclomaltooligosaccharide (cyclodextrin, CD) derivative containing sulfopropyl functional groups on the primary face of the CD was synthesized. Heptakis(2,3-di-O-methyl)cyclomaltoheptaose [heptakis(2,3-di-O-methyl)-beta-cyclodextrin] was reacted with 1,3-propane sultone and potassium hydride (KH) in anhydrous tetrahydrofuran in the presence of 18-crown-6 to yield highly substituted potassium heptakis(2,3-di-O-methyl-6-O-sulfopropyl)cyclomaltoheptaose [heptakis(KSPDM)-beta-CD] with an average degree of substitution (DSCE) of 6.9 as determined by inverse detection capillary electrophoresis (CE). The principal species in the product is the fully substituted heptakis(KSPDM)-beta-CD. Complete NMR assignments of the hydrogen and carbon atoms are made using a combination of gCOSY and gHSQC. In the absence of 18-crown-6, the reaction generates a mixture of multiply charged derivatives with average DSCE of 4.1. The possible roles of the crown ether in the reaction are discussed. The ROESY NMR spectrum of the inclusion complex that forms between heptakis(KSPDM)-beta-CD and 2-naphthoic acid in D2O reveals that 2-naphthoic acid inserts with the carboxyl group toward the derivatized primary rim of the cyclodextrin. 相似文献
8.
A facile procedure is described for the preparation of [14C]epicholesterol from [14C]cholesterol. Cholesterol is first converted to cholesteryl mesylate, which is treated with cesium acetate and 18-crown-6 in refluxing toluene to give epicholesteryl acetate. The latter is hydrolyzed, without isolation, with potassium hydroxide in tetrahydrofuran-methanol to give epicholesterol, which is obtained in pure form by preparative thin-layer chromatography. 相似文献
9.
Tamara M. Polyanskaya Elizaveta P. Simonenko Nikolay T. Kuznetsov 《Inorganica chimica acta》2009,362(15):5133-5138
The trans-[M(18-crown-6)(C5HO2F6)2] (M = Ca, Sr, Ba, Pb) complexes have been synthesized and identified. The crystal structure of the Sr complex has been determined by X-ray diffraction. The basic structural unit is the mononuclear complex trans-[Sr(18-crown-6)(C5HO2F6)2]. The thermal properties of the complexes have been correlated to their structure. The melting and decomposition ranges of the Ca, Sr and Ba complexes and their sublimation temperatures at ∼10−2 mm Hg have been determined. Experimental evidence is presented that the complexes are similar in volatility. 相似文献
10.
M Ouchi Y Shibutani K Yakabe T Shono H Shintani A Yoneda T Hakushi E Weber 《Bioorganic & medicinal chemistry》1999,7(6):1123-1126
Dibenzo-16-crown-4 (1) indicates high silver and thallium(I) ion selectivity over sodium, potassium, and rubidium ion evaluated from the solvent extraction of metal picrates, while its cation-binding ability is lower than those of dibenzo-18-crown-6 (2) and dibenzo-22-crown-6 (3). Taking account of the highest thallium(I) ion selectivity for 1 obtained from extraction experiments, PVC membrane thallium(I)-selective electrodes based on 1 are prepared. The electrode shows the best potentiometric selectivity coefficients for thallium(I) over potassium and rubidium than those of 2 and 3, and commercially available bis(crown ether)s (4). 相似文献
11.
Gaballa A Schmidt H Hempel G Reichert D Wagner C Rusanov E Steinborn D 《Journal of inorganic biochemistry》2004,98(3):439-446
Na(2)[PtCl(6)] was found to react with (9-MeAH)Cl(.)H(2)O (2) (9-MeA=9-methyladenine) in aqueous solution yielding (9-MeAH)(2)[PtCl(6)](.)2H(2)O (3). The same compound was obtained from hexachloroplatinic acid and 9-methyladenine. Performing this reaction at 60 degrees C, complex formation took place yielding the 9-methyladeninium complex [PtCl(5)(9-MeAH)](.)2H(2)O (4a). An analogous complex, [PtCl(5)(9-MeAH)](.)1/2(18C6)(.)H(2)O (4b, 18C6=crown ether 18-crown-6), was formed in the reaction of aquapentachloroplatinic acid (H(3)O)[PtCl(5)(H(2)O)](.)2(18C6)(.)6H(2)O (1) with 9-methyladenine in 1:1 ratio. All complexes were isolated in moderate to good yields as yellow powder (4b) and crystals (3, 4a), respectively. They were fully characterized by microanalysis, IR and NMR ((1)H, (13)C, (195)Pt) spectroscopies, and in part (2, 3, 4a) also by single-crystal X-ray diffraction analysis. Molecular structure of complex 4a exhibited that the 9-methyladeninium ligand is N1 protonated and coordinated through N7 to platinum(IV). 相似文献
12.
Valinomycin binds to soluble and reconstituted cytochrome c oxidase (COX) in a stoichiometric manner, as shown by a spectral shift of the oxidized gamma-band. No spectral change is found with nigericin or 18-crown-6 and in the absence of potassium ions. Titration of the proton pumping activity of reconstituted COX with valinomycin reached a maximum of H+/e- - 0.73 after addition of 1 mole of valinomycin per mole of reconstituted COX. It is concluded that K+-translocation in proton-pumping COX vesicles occurs via enzyme-bound valinomycin. 相似文献
13.
Weltrowska G Lu Y Lemieux C Chung NN Schiller PW 《Bioorganic & medicinal chemistry letters》2004,14(18):4731-4733
2',6'-Dimethyl substitution of the Tyr(1) residue in opioid agonist peptides and deletion of the N-terminal amino group, as achieved by replacement of Tyr(1) with 3-(2,6-dimethyl-4-hydroxyphenyl)propanoic acid (Dhp), have been shown to produce opioid antagonists. To examine the effect of beta-methylation of Dhp(1) in opioid peptides on the activity profile, stereoselective syntheses of (3S)- and (3R)-3-methyl-3-(2,6-dimethyl-4-hydroxyphenyl)propanoic acid [(3S)- and (3R)-Mdp] were carried out. In comparison with the cyclic parent antagonist peptide Dhp-c[D-Cys-Gly-Phe(pNO(2))-D-Cys]NH(2), the methylated analogue (3S)-Mdp-c[D-Cys-Gly-Phe(pNO(2))-D-Cys]NH(2) showed higher micro, delta and kappa antagonist potencies in functional assays and higher binding affinities for micro, delta and kappa opioid receptors (K(i)(micro)=2.03 nM; K(i)(delta)=2.34 nM; K(i)(kappa)=49.5 nM), whereas the corresponding (3R)-Mdp(1)-analogue was less potent by 1-2 orders of magnitude. 相似文献
14.
James M. Harrington Donald J. VanDerveer Robert D. Hancock 《Inorganica chimica acta》2009,362(4):1122-13190
The role of relativistic effects (RE) in the structures of Cd(II) complexes with crown ethers, and the reason the ‘soft’ Cd(II) strongly prefers to bind to SCN− through N, are considered. The synthesis and structures of [Cd(18-crown-6)(thiourea)2] (ClO4)2.18-crown-6 (1) and [Cd(Cy2-18-crown-6)(NCS)2] (2) are reported. (18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane; Cy2-18-crown-6 = cis-anti-cis-2,5,8,15,18,21-hexaoxatricylo[20.4.0.0(9,14)]hexacosane). In 1 Cd is coordinated in the plane of the crown which has close to D3d symmetry, with long Cd-O bonds averaging 2.688 Å. The two thiourea molecules form relatively short Cd-S bonds that average 2.468 Å, with an S-Cd-S angle of 164.30°. This structure conforms with the idea that Cd(II) can adopt a near-linear structure involving two covalently-bound donor atoms (the S-donors) with short Cd-S bonds, which resembles gas-phase structures for species such as CdCl2. The structure of 2 is similar, with the two SCN− ligands N-bonded to Cd, with short Cd-N bonds of 2.106 Å, and N-Cd-N angle of 180°. The crown in 2 forms long Cd-O bonds that average 2.698 Å. Molecular mechanics calculations suggest that a main reason Cd(II) prefers to bind to SCN− through N is that when bound through S, the small Cd-S-C angle, which is typically close to 100°, brings the ligand into close contact with other ligands present, and causes steric destabilization. In contrast, the Cd-N-C angles for SCN− coordinated through N are much larger, being 171.4° in 2, which keeps the SCN− groups well clear of the crown ether. DFT (density functional theory) calculations are used to generate the structures of [Cd(18-crown-6)(H2O)2]2+ (3) and [Cd(18-crown-6)Cl2] (4). In 3, the Cd(II) is bound to only three O-donors of the macrocycle, with Cd-O bonds averaging 2.465 Å. The coordinated waters form an O-Cd-O angle of 139.47°, with Cd-O bonds of 2.295 Å. In contrast, for 4, the Cd is placed centrally in the cavity of the D3d symmetry crown, with long Cd-O bonds averaging 2.906 Å. The Cl groups form a Cl-Cd-Cl angle of 180°, with short Cd-Cl bonds of 2.412 Å. With ionically bound groups on the axial sites of[Cd(18-crown-6)X2] complexes, such as with X = H2O in 3, the Cd(II) does not adopt linear geometry involving the two X groups, with long Cd-O bonds to the O-donors of the macrocycle. With covalently-bound X = Cl in 4, short Cd-Cl bonds and a linear [Cl-Cd-Cl] unit results, with long Cd-O bonds to the crown ether. 相似文献
15.
MACKLON A. E. S.; SIM A.; PARSONS D. G.; TRUTER M. R.; WINGFIELD J. N. 《Annals of botany》1983,52(3):345-356
The ionophores benzo-18-crown-6 (18-C-6), t-butylbenzo-18-crown-6(TBB) and di-t-butyldibenzo-30-crown-10 (30-C-10) were testedfor their effects on potassium ion absorption in onion rootsegments, and in wheat and mung bean seedlings. Potassium uptake,efflux and transport were progressively reduced in onion rootsegments and seedlings by 18-C-6 over the range 0.11.0mM. The effects of TBB (up to 0.3 mM) were more severe but otherwisegenerally similar to those of 18-C-6 in seedlings. Both ionophoresreduced growth, and at the highest concentrations, resultedin root potassium ion content falling below initial values after48 h treatment. The effects of 30-C-10 were evident at muchlower concentrations, inhibition of net potassium uptake occurringabove 104 M. Between 104 and 104 M 30-C-10,however, a modest but significant stimulation of potassium uptakewas observed in onion roots and seedlings; growth of seedlingswas largely unaffected. The reductions in potassium absorptionwere attributed to the promotion, by the ionophores, of facilitateddiffusion down the electrochemical diffusion gradient, counteringthe efficiency of the potassium ion influx pump. Stimulationof uptake at certain concentrations of 30-C-10 was consideredmore likely to be due to an inhibition of passive potassiumefflux, rather than a stimulation of active influx. The importanceof stability constants, bonding and lipophilicity, in determiningthe relative effectiveness of the ionophores, is discussed. Allium cepa L, onion, Triticum aestivum L, wheat, Phaseolus aureus L, mung bean, cyclic crown polyethers, potassium fluxes, ion transport 相似文献
16.
Messori L Marcon G Cinellu MA Coronnello M Mini E Gabbiani C Orioli P 《Bioorganic & medicinal chemistry》2004,12(23):6039-6043
The solution behaviour of some novel organogold(III) compounds was investigated, and their cytotoxic properties evaluated against a few human tumour cell lines (A2780/S, A2780/R, MCF7, HT29 and A549). Specifically, the following compounds were considered: [Au(bipy(dmb)-H)(2,6-xylidine-H)][PF(6)] (AuXyl) and [Au(bipy(dmb)-H)(p-toluidine-H)][PF(6)] (AuTol) (in which bipy(dmb)=6-(1,1-dimethylbenzyl)-2,2'-bipyridine), [Au(py(dmb)-H)(AcO)(2)] (AuPyAcO) (in which py(dmb)=2-(1,1-dimethylbenzyl)-pyridine) and [Au(pz(Ph)-H)Cl(3)]K (AuPzCl) (in which pz(Ph)=1-phenylpyrazole). The solution chemistry of these compounds, under physiological-like conditions, was investigated through UV-vis absorption and (1)H NMR spectroscopies. Significant cytotoxic effects in vitro were observed in selected cases. 相似文献
17.
Crown ethers are toxic to Escherichia coli. At a sublethal dosage, the crown ether affects the three phases in the bacterial growth curve as evidenced by an appearance of a lag period, an occasional decrease in the stationary phase at a lower microbial population. Potassium ion but not sodium ion can reduce the lag induced by the presence of 18-crown-6. On the contrary, the presence of either potassium ion or sodium ion lengthens the lag due to substituted 18-crown-6 ethers. Explanations to this variable toxicity are proposed. 相似文献
18.
Arif MI Samin G van Leeuwen JG Oppentocht J Janssen DB 《Applied and environmental microbiology》2012,78(17):6128-6136
A Pseudomonas putida strain (MC4) that can utilize 2,3-dichloro-1-propanol (DCP) and several aliphatic haloacids and haloalcohols as sole carbon and energy source for growth was isolated from contaminated soil. Degradation of DCP was found to start with oxidation and concomitant dehalogenation catalyzed by a 72-kDa monomeric protein (DppA) that was isolated from cell lysate. The dppA gene was cloned from a cosmid library and appeared to encode a protein equipped with a signal peptide and that possessed high similarity to quinohemoprotein alcohol dehydrogenases (ADHs), particularly ADH IIB and ADH IIG from Pseudomonas putida HK. This novel dehalogenating dehydrogenase has a broad substrate range, encompassing a number of nonhalogenated alcohols and haloalcohols. With DCP, DppA exhibited a k(cat) of 17 s(-1). (1)H nuclear magnetic resonance experiments indicated that DCP oxidation by DppA in the presence of 2,6-dichlorophenolindophenol (DCPIP) and potassium ferricyanide [K(3)Fe(CN)(6)] yielded 2-chloroacrolein, which was oxidized to 2-chloroacrylic acid. 相似文献
19.
Alexander Y. Verat Felix D. Sokolov Nail G. Zabirov Dmitry B. Krivolapov Igor A. Litvinov 《Inorganica chimica acta》2006,359(2):475-483
Heteroligand copper(I) complexes of bi- or bis-bidentate acylamidophosphates PhC(S)NHP(S)(OPr-i)2, PhC(S)NHP(O)(OPr-i)2, Et2NC(S)NHP(S)(OPr-i)2, PhNHC(S)NHP(S)(OPr-i)2, N-(4-aminobenzo-15-crown-5)-C(S)NHP(S)(OPr-i)2, N,N-(1,10-diaza-18-crown-6)-[C(S)NHP(S)(OPr-i)2]2, and triphenylphosphine were prepared and characterised. Copper is bound by two PPh3 and one SCNPX (X = O, S) fragment of chelating ligand in all cases. Triphenylphosphine molecules reversibly dissociate in solution. Details of the X-ray structures of (Ph3P)2Cu[PhC(S)NP(S)(OPr-i)2] and (Ph3P)2Cu[Et2NC(S)NP(S)(OPr-i)2] are reported. 相似文献
20.
H. B. Lazrek M. Taourirte J.-L. Barascut J.-L. Imbach 《Nucleosides, nucleotides & nucleic acids》2013,32(6):1285-1293
Abstract N-alkylation with acyclic side chains of pyrimidine and purine heterocycles occurs regioselectively at N-1 and N-9 respectively under solid-liquid phase transfer catalysis by 18-crown-6 or tetraglyme in the presence of potassium tert-butoxide at 0°C. 相似文献