bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conductometric Study of Ion-Ion and Ion-Solvent Interactions. III. Conductances of Silver Acetate in Acetonitrile–Water Mixtures at 25 °C
Authors: Raju U G Krishnam , Sethuram Bangalore , Rao T Navaneeth 
Published: July 2006

Abstract
Conductances of the solutions of silver acetate in 10 to 90% (w/w) acetonitrile–water mixtures were measured at 25 °C. The molar conductances at infinite dilution and association constants were calculated, using the Fuoss-Hsia equation with Fernandez-Prini coefficients. There was no association in 10 and 20% acetonitrile. The logKA vs. 1/D plot was a straight line with negative intercept in accordance with the modified Denison-Ramsey theory of ion-pair formation. Walden products were also calculated. From these results it was concluded that silver ions are preferentially solvated by acetonitrile whereas acetate ion is hydrated in acetonitrile–water mixtures.
The Crystal and Molecular Structures of Tetronolide
Authors: Hirayama Noriaki , Kasai Masaji , Shirahata Kunikatsu , Ohashi Yuji , Sasada Yoshio 
Published: July 2006

Abstract
Tetronolide is an aglycone moiety of novel antitumor antibiotics tetrocarcins. The space group of the crystal is P212121 with a=20.138(3), b=22.680(3), c=7.848(1) Å and Z=4. The structure was solved by direct methods and refined by the block-diagonal least-squares using 3577 independent reflexions. The final R value was 0.085. It is established that tetronolide is [1R-(1R*,3R*,4R*,4aR*,6aR*,7E,10R*,11E,12aS*,13R*,16aR*,20aR*,20bS*)]-1,2,3,4,4a,6a,9,10,12a,13,16,20,20a,20b-tetradecahydro-4,10,13,21-tetrahydroxy-1,3,7,11,20a-pentamethyl-18,20-dioxo-18H-16a,19-metheno-16aH-benzo[b]naphth[2,1-j]oxacyclotetradecin-15-carbaldehyde or its enantiomer.
Adsorption of Surface Active Agents on Coals
Authors: Esumi Kunio , Meguro Kenjiro , Honda Hidemasa 
Published: July 2006

Abstract
The interactions between surface active agents and coals with various carbon contents were studied by measuring adsorption isotherms and zeta potentials. A characteristic adsorption behavior was observed for the coals among three different surface active agents, but no correlation was found between the adsorption and the carbon content of the coal.
Copper(II) Complexes of Schiff Bases Derived from Histamine or 2-(2-Aminoethyl)pyridine and 2,3-Butanedione or 4-Hydroxy-4-methyl-2-pentanone
Authors: Abe Masahiro , Nakao Yasuo , Suzuki Shinnichiro , Kimura Masazo , Nakahara Akitsugu 
Published: July 2006

Abstract
Copper(II) complexes of Schiff bases derived from histamine or 2-(2-aminoethyl)pyridine and 2,3-butanedione or 4-hydroxy-4-methyl-2-pentanone were prepared and characterized by elemental analyses, electronic and ESR spectra, and polarographic half-wave potentials. The relationship between structure of the chelates and the reduction potentials of copper(II) in these complexes was discussed in some detail.
Chemical Studies on the Mistletoe. IV. The Structure of Isoglucodistylin, a New Flavonoid Glycoside Isolated from Taxillus kaempferi
Authors: Sakurai Atsushi , Okada Kyoji , Okumura Yasuaki 
Published: July 2006

Abstract
A new flavonoid glycoside, isoglucodistylin was isolated from Taxillus kaempferi, and (2R,3S)-taxifolin 3-β-d-glucopyranoside was assigned to this substance from studies on the hydrolysis products and on the isomerization products, and from analyses of the carbon-13 NMR spectra.
The Behavior of Carbon Black in a Detergent Solution
Authors: Yoneyama Yuji , Ogino Keizo 
Published: July 2006

Abstract
The behavior of carbon black (CB) in a detergent (sodium dodecyl sulfate (SDS): 20%, zeolite: 20%, sodium silicate: 5%, sodium carbonate: 3%, sodium (carboxylatomethyl)cellulose (CMC): 1%, sodium sulfate: 51%) solution is discussed in terms of the ζ-potential and potential energy of interaction. The ζ-potential of CB in each solution of SDS, various builders, and the detergent was measured by microelectrophoresis. The potential energies between CB and fabrics (nylon and cellulose), between CB and clay, and between CB and zeolite were calculated by the use of the theory of heterocoagulation. The potential energy between one CB particle and another CB particle was calculated by the use of D-L-V-O theory. The ζ-potential was increased by the addition of builders, except sodium sulfate. The high negative ζ-potential of CB in the detergent solution resulted from the effect of builders. From the potential energies, it became evident that 1) CB in the detergent solution deposits with difficulty onto fabrics; 2) The CB coagulates with zeolite only with difficulty; 3) The CB coagulates with clay or CB.
The Isomerization of Butenes over KC8
Authors: Tsuchiya Susumu , Misumi Takatoshi , Ohuye Noriyuki , Imamura Hayao 
Published: July 2006

Abstract
The isomerization of butenes over KC8 has been investigated. The double-bond-migration and the cis-trans isomerization took place over KC8, but the skeletal isomerization could not be observed. From the rates of reactions and the selectivity ratios, all six of the relative rate constants and the activation energies of reaction were determined. The reaction paths on the triangular graph calculated from the rates constants show the cis-convex-type profile, which suggests one of the catalytic characteristics of KC8.
Radiationless Transition between Randomly Fluctuating Levels. S1-T2-T1 Intersystem Crossing in Condensed Phase
Authors: Kanamaru Nobuaki 
Published: July 2006

Abstract
Radiationless transitions in aromatic molecules in condensed phase are examined for the case where sparse intermediate levels are involved. Effects of surrounding mediums on radiationless transitions are also discussed in which the random fluctuation of the vibrational manifolds in the solvent cages is shown to be important to meet the resonance conditions in the transitions. The theory is applied to explain the “unusually” fast S1-T2-T1 intersystem crossing in the system such as anthracene derivatives.
Substituent Effect on a Photo-Smiles Rearrangement by Laser Photolysis
Authors: Yokoyama Kenji , Nakamura Junko , Mutai Kiyoshi , Nagakura Saburo 
Published: July 2006

Abstract
The photo-Smiles rearrangement was studied for two homologues of N-[2-(4-nitrophenoxy)ethyl]aniline by laser photolysis, an importance being attached to the effect of the alkoxyl substituent on the reactive position. The nitro group enhances the substitution at the para position, but the alkoxyl group does not play a significant role in the photosubstitution of the molecules.
Extraction of Titanium(IV)–Pyrocatechol Violet Complex with Tridodecylethylammonium Bromide
Authors: Shijo Yoshio , Shimizu Tokuo , Sakai Kaoru 
Published: July 2006

Abstract
The extraction equilibria and the fundamental conditions for extracting the titanium(IV)–Pyrocatechol Volet complex anion in a form of an ionic associate with tridodecylethylammonium bromide into carbon tetrachloride is described. The absorption maxima of the extracted complex occurs at 586 nm, the molar absorptivity and the distribution ratio being 5.17×104 dm3 mol−1 cm−1 and 2.82×102. The optimum pH range for the extraction is 5.1–6.4. The composition of the complex is estimated to be Ti(PV)2(R3R′N)2. The extraction constant would be:
K ex=\frac[Ti(PV)2(R3R′N)2]0[Ti(PV)22−][R3R′N+]2,
logKex obtained is 13.5. The interference of foreign ions is discussed.
Effects of N-Methylated Diamine on Ion Pair Formation of Bis(2,4-pentanedionato)(diamine) Cobalt(III) Bromides in Nitrobenzene by Conductometry
Authors: Ito Kazuaki , Iwamoto Etsuro , Yamamoto Yuroku 
Published: July 2006

Abstract
The conductometric study of bis(2,4-pentanedionato)(diamine) cobalt(III) bromides in nitrobenzene at 25 °C indicated that the ion association constant of the chelate salts increases in the order, [Co(acac)2(N,N,N′,N′-tmen)]Br&lt;Bu4NBr&lt;[Co(acac)2(N,N-dmen)]Br&lt;[Co(acac)2(en)]Br&lt;[Co(acac)2(N,N′-dmen)]Br (acac=2,4-pentanedione anion, diamine: en=ethylenediamine, N,N-dmen= N,N-dimethylethylenediamine, N,N′-dmen=N,N′-dimethylethylenediamine, N,N,N′,N′-tmen=N,N,N′,N′-tetramethylethylenediamine). The results were discussed from the view points of hydrogen bonds through the N–H protons of the chelate cations to the bromide anion and cation-solvent interactions.
Synthesis of 3-Acylfurans Using 3-(Phenylthio)propanal Dimethyl Acetal as a New Synthon. Syntheses of Ipomeanine and Isoegomaketone
Authors: Watanabe Eiji , Imai Naohiro , Inomata Katsuhiko , Kinoshita Hideki , Kotake Hiroshi 
Published: July 2006

Abstract
It was found that 3-(phenylthio)propanal dimethyl acetal is a very useful starting material for the preparation of 3-acylfuranoterpenes. Syntheses of two naturally-occurring furans, isoegomaketone and ipomeanine were described.
Total Synthesis of a Macrocyclic Lactone Antibiotic A26771B and Its Isomers Using Carbohydrates
Authors: Tatsuta Kuniaki , Amemiya Yoshiya , Kanemura Yoshinobu , Kinoshita Mitsuhiro 
Published: July 2006

Abstract
Total synthesis and antibacterial activities of a macrocyclic lactone antibiotic A26771B (1) and all its isomers (2, 3, and 4) are discussed. The starting 8,9,10,12-tetra-O-benzyl-2,3,4,5,11-pentadeoxy-aldehydo-d-xylo-(E)-6-dcdecenose derived from d-glucose reacted with racemic Wittig reagent, (3-hydroxybutyl)triphenylphosphonium iodide to give 1,3,4,5-tetra-O-benzyl-2,8,9,10,11,14,16-heptadeoxy-Dl-glycero-l-xylo-hexadeca-6,12-dienitol, which was in turn converted into methyl 15-O-acetyl-6,7,8,9,10,11,12,13,14,16 -decadeoxy-4,5-O-isopropylidene-Dl-glycero-l-threo-(E)-2-hexadecenonate (13) through effective oxidation and β-elimination. Saponification followed by Yamaguchi’s lactonization of 13 afforded two diastereomeric 16-membered-ring lactones which were converted into (5S, 15R)-A26771B (1) and its (5S, 15S-diastereomer (2) by successive deacetonation, selective succinylation and oxidation. The other starting 2,3,4,6-tetra-O-benzyl-5-deoxy-aldehydo-d-lyxo-hexose, which was prepared from 2-deoxy-d-glucose, reacted with a Wittig reagent to give 8,9,10,12-tetra-O-benzyl-2,3,4,5,11-pentadeoxy-aldehydo-d-lyxo-6-dodecenose (20) followed by hydrol ysis. Similar reaction sequence from 20 with the aforesaid series for 1 and 2 afforded the (5R, 15R)-isomer (3) and (5R, 15S)-isomer (4).
Acetolysis of [4.2.2]Propellan-7-ylmethyl Tosylates
Authors: Tobe Yoshito , Yonezawa Tetsuo , Kakiuchi Kiyomi , Odaira Yoshinobu 
Published: July 2006

Abstract
The acetolysis rates and products of [4.2.2]propellan-7-ylmethyl tosylates were determined in order to clarify the effect of the central and external cyclobutane bonds on the modes of the ring expansion of the cyclobutylmethyl moiety. Since the products obtained from the endo tosylate were the olefin and the acetate having 1,7-tetramethylenenorbornane skeleton, it is deduced that the ring expansion occurs selectively to afford [4.3.2]propellan-7-yl cation which is stabilized by the external cyclobutane bond. In contrast, the exo tosylate gave the products derived from both [4.3.2]propellan-7-yl and -8-yl cations which are subject to the participation of the external and central cyclobutane bonds, respectively.
A Voltammetric Study of the Reduction of Ruthenium(II) Complexes with Mixed Ligands
Authors: Watanabe Junya , Saji Tetsuo , Aoyagui Shigeru 
Published: July 2006

Abstract
Each cyclic voltammogram for the reduction of [Ru(bpm)3]2+ (bpm=2,2′-bipyrimidine) and [Ru(bpm)L2]2+ (L=2,2′-bipyridine and dimethyl derivatives) exhibits three reversible one-electron steps. The relation between the half-wave potentials of the complexes and those of ligands suggests that the lowest redox orbital of [Ru(bpm)L2]2+ should be localized on a single bpm molecule.
Pyrolytic Sulfurization Gas Chromatography. X. The Reduction of the Analysis Time by Means of High-frequency Heating
Authors: Hara Tadashi , Okui Fujio 
Published: July 2006

Abstract
With the objective of reducing the analysis time in the previous PSGC method, a high-frequency induction furnace was used instead of an electric furnace. By using the present furnace, the time necessary for the pyrolytic sulfurization was reduced from 40 min to 1 min with satisfactory results.
Glass Formation in the HI + Water System
Authors: Akama Yoshifumi , Kanno Hitoshi 
Published: July 2006

Abstract
Glass transition temperature (Tg) of aqueous HI solution was measured as a function of HI concentration. The Tg data of aqueous HI solution suggest an anomalously low Tg value for glassy bulk pure water. Double-glasstransition phenomenon is observed at the water-rich edge of glass-forming composition range.
Dysprosium and Holmium Complexes of N(2-Pyridyl)salicylideneamine
Authors: Singh Megh , Gharia K Singh 
Published: July 2006

Abstract
Dysprosium and holmium isopropoxides react with monofunctional bidentate Schiff base, N-(2-pyridyl)salicylideneamine, in 1:1, 1:2, and 1:3 molar ratios in benzene to yield complexes of the types Ln(OPri)2(sap), Ln(OPri)(sap)2, and Ln(sap)3 (where Ln=Dy or Ho and sap− is the anion of the Schiff base sapH). Probable structures for these complexes are proposed on the basis of molecular weight and IR spectroscopic data. Reports on metal complexes derived from Schiff bases have aroused considerable interest in the field of coordination chemistry, and have been extensively studied. A literature survey reveals that no work has been done on Dy(III) and Ho(III) complexes of heterocyclic Schiff base, N-(2-pyridyl)salicylideneamine. However, complexes of this Schiff base with d-transition elements have been reported. The present paper deals with the synthesis of Dy(III) and Ho(III) complexes of N-(2-pyridyl)salicylideneamine and their characterization by infrared spectra.
Time-resolved Emission Spectra of 2-Acetylanthracene/Methanol/Hexane System. Evidence for the Photoassociation of a 1:2 Hydrogen Bonded Complex
Authors: Tamaki Takashi 
Published: July 2006

Abstract
The deconvolved time-resolved emission spectra of 2-acetylanthracene in hexane containing 0.1 mol dm−3 of methanol revealed a considerable time-dependent spectral shift associated with the photoassociation of the hydrogen-bonded complex which includes two methanol molecules.
Effect of Temperature and Solvent on the 1,3-Dipolar Cycloaddition of Diazodiphenylmethane with Several Dipolarophiles
Authors: Yoshimura Yosuke , Osugi Jiro , Nakahara Masaru 
Published: July 2006

Abstract
The title reaction is studied with a series of CN- or COOCH3-substituted dipolarophiles. All the reactions obey the second-order rate law. The activation enthalpies and entropies are 44–52 kJ mol−1 and −(129–166) J K−1 mol−1, respectively. The rate constants are insensitive to solvent. The reactivity and product of dimethyl maleate are anomalous.
The Reaction of 2-Benzylidenetetralin-1-thione S-oxide with Acrylonitrile or Styrene
Authors: Ohmura Haruo , Karakasa Takayuki , Satsumabayashi Sadayoshi , Motoki Shinichi 
Published: July 2006

Abstract
The cycloaddition reaction of 2-benzylidenetetralin-1-thione S-oxide with acrylonitrile (or styrene) gave a mixture of 2- and 3-cyano(or phenyl)-4-phenyl-3,4,5,6-tetrahydro-2H-naphtho[1,2-b]thiopyran S-oxide. Pummerer reaction of these S-oxides resulted to afford the corresponding acetates.
Chemical Reaction Following Electroreduction of Benzophenones. 2. Relationship between the Rate Constant of Disproportionation and Spin Density
Authors: Egashira Naoyoshi , Takita Yusaku , Hori Fumiaki 
Published: July 2006

Abstract
Electroreduction of benzophenones in DMF in the presence of Li+ was investigated by cyclic voltammetry. Most of these radical anions underwent disproportionation reactions. The relationship between the logarithm of the rate constant of the reaction and the spin density of the carbon atom at the carbonyl group was found to be linear.
Redox Reaction of the Central Metal Ions Coordinated to Tetra(p-sulfophenyl)porphine (TPPS). II. Photoreduction of [Fe(III)TPPS]2O by Ethanol
Authors: Hatano Keiichiro , Ishida Yoshitaka 
Published: July 2006

Abstract
Iron(III) ion coordinated to TPPS was reduced to the divalent ion by ethanol on illumination of light. The reaction rates appear to obey the half-order kinetic of the metalloporphyrin in the buffered solutions of pH 7 to 11. A possible reaction mechanism is discussed.
α-Pentafluoropropionylation of Ketones and Aldehydes Using Hexafluoropropene Oxide. A Facile Synthesis of Fluorinated 1,3-Diketones
Authors: Ishihara Takashi , Seki Toshio , Ando Teiichi 
Published: July 2006

Abstract
Hexafluoropropene oxide reacts smoothly with morpholine enamines from ketones and aldehydes at 0 °C to room temperature in anhydrous THF to give pentafluorinated 1,3-diketones in good yields. The keto-enol equilibrium in the products is generally in favor of their enol form.
Electrooxidative Conversion of Aldehydes into Methyl Carboxylates
Authors: Chiba Toshiro , Okimoto Mitsuhiro , Nagai Hiroshi , Takata Yoshiyuki 
Published: July 2006

Abstract
The electrolytic oxidation of methanolic solutions of aldehydes in the presence of sodium cyanide at a platinum anode was found to produce corresponding methyl carboxylates.
Resonance Raman Spectra and Inter-radical Vibrations of Chloranil Anion Radical Dimers
Authors: Matsuzaki Susumu , Mitsuishi Tetsuya , Toyoda Koichi 
Published: July 2006

Abstract
Resonance Raman spectra of chloranil anion radical dimers were measured in ethanol at 140 K by an exciting radiation within the CT band, and all the Raman lines observed were shown to be totally symmetric. Two strong Raman lines at 114 cm−1 and 168 cm−1 have been assigned to inter-radical stretching vibrations of the dimer. The relative intensity of these lines changed depending on the counter ion species. Formation of two dimers has been supposed to explain the spectral behavior. Influence of 18-crown-6 on the spectra was investigated. The result strongly suggests that one dimer gives two inter-radical Raman lines. Two interpretations are proposed for the simultaneous resonance enhancement of these Raman lines: mechanical coupling of the inter- and intra-radical vibrations or distorsion of the D2h eclipsed dimer structure. Other five lines at higher frequencies have been assigned to intra-radical vibrations of the dimer.
The Reactions of the 1,2-Ethanediylbis(trithiocarbonic acid) Dianion with Several Electrophilic Reagents
Authors: Tanimoto Shigeo , Oida Tatsuo , Kokubo Toshio , Okano Masaya 
Published: July 2006

Abstract
It has been found that the reaction of the 1,2-ethanediylbis(trithiocarbonic acid) dianion with haloacetic esters, chloromethyl ethers, and chlororhethyl sulfides in tetrahydrofuran proceeds smoothly to afford 1,2-ethanediylbis(alkoxycarbonylmethyl trithiocarbonates), 1,2-ethanediylbis(alkoxymethyl trithiocarbonates) and bis(alkylthiomethyl) trithiocarbonates plus ethylene trithiocarbonate respectively.
Further Studies of Electroluminescence Spectra of the n-GaP Semiconductor Electrode in Relation with the Surface-trapped Holes
Authors: Nakato Yoshihiro , Tsumura Akira , Tsubomura Hiroshi 
Published: July 2006

Abstract
Electroluminescence spectra of an n-type gallium phosphide (n-GaP) electrode caused in the presence of oxidants such as [Fe(CN)6]3− and S2O82− were measured as functions of the electrode potential, the solution pH, and the kind of crystal faces. The electroluminescence spectra consisted of two bands; one was assigned to arise from electronic transitions in the bulk and the other from those at the surface. It was found that the position and the spectral shape of the luminescence band arising from the surface were quite independent of various experimental conditions, while its intensity was strongly dependent on them. These results were explained well by the view that the luminescence band is caused by “surface-trapped holes” acting as a precursor of anodic dissolution reaction of the electrode, as proposed previously. The physicochemical model of the surface-trapped hole was discussed on the basis of the above results.
The Crystal and Molecular Structure of 7,8-Epoxyhalochamigrene
Authors: Furusaki Akio , Katayama Chuji , Matsumoto Takeshi , Suzuki Minoru , Suzuki Teruaki , Kikuchi Hajime , Kurosawa Etsuro 
Published: July 2006

Abstract
The molecular structure of 7,8-epoxyhalochamigrene, C15H23OBr2Cl, has been confirmed by means of X-ray crystallographic analysis. The crystals are orthorhombic, with sixteen molecules in a unit cell with dimensions of a=10.303, b=71.31, and c=9.061 Å; the space group is P212121. 4241 independent intensity data were collected on a four-circle diffractometer with graphite-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using 20 reflections as a starting set, and was refined by the block-diagonal least-squares method. The final R value was 0.072. The molecular structure thus obtained corresponds to that proposed by Howard and Fenical on the basis of chemical and spectroscopic evidence. The four crystallographically-independent molecules have almost the same geometries. Of the two spiro-linked six-membered rings, the one having the epoxy group takes a half-chair conformation, while the other adopts a chair conformation. The crystal consists of alternating single and triple molecular layers parallel to the (010) plane; the latter layer has a molecular arrangement approximately of P212121 symmetry.
The Solvent Extraction of Silver and Thallium(I) Picrates by Crown Ethers
Authors: Takeda Yasuyuki , Nemoto Masashi , Fujiwara Shizuo 
Published: July 2006

Abstract
Extraction constants of silver and thallium(I) picrates and those of 12-crown-4 (12C4) and benzo-15-crown-5(B15C5) with silver and thallium(I) picrates have been determined between benzene and water at 25 °C. Ionpair complex-formation constants (KMLA,o) of 12C4 and B15C5 with silver and thallium picrates in the benzene solution have been calculated and compared with those of 15-crown-5 (15C5), 18-crown-6 (18C6), dibenzo-18-crown-6 (DB18C6), and dibenzo-24-crown-8 (DB24C8). The KMLA,o sequences of the crown ethers with Ag+ and Tl+ are 15C5, 18C6&gt;DB18C6&gt;B15C5&gt;DB24C8&gt;&gt;12C4 and 18C6&gt;&gt;DB18C6&gt;DB24C8&gt;15C5&gt;B15C5&gt;&gt;12C4, respectively. For both Ag+ and Tl+ systems, the relative sizes of the cation and the crown ether cavity, the number of donor oxygen atoms in the crown ether ring, the basicity of donor oxygen atom, and the flexibility of the crown ether are important factors in determining stabilities of the complexes with these crown ethers in the benzene solution.
Cyclization of Isomeric 2-Hydrazino-4-methylbenzo[h]quinoline and 3-Hydrazino-1-methylbenzo[f]quinoline. A Reinterpretation
Authors: Kocevar Marjan , Polanc Slovenko , Stanovnik Branko , Škerjanc Franc , Tišler Miha 
Published: July 2006

Abstract
Cyclization of 2-hydrazino-4-methylbenzo[h]quinoline and 3-hydrazino-1-methylbenzo[f]quinoline with formic acid occurs on nitrogen rather than carbon to give 5-methylbenzo[h][1,2,4]triazolo[4,3-a]quinoline and 11-methylbenzo[f][1,2,4]triazolo[4,3-a]quinoline and not 7-methyl-10H-benzo[h]pyrazolo[3,4-b]quinoline and 11-methyl-8H-benzo[f]pyrazolo[3,4-b]quinoline, respectively, as it has been claimed before.
Solvent Extraction of Alkali Metal Picrates with Poly- and Bis(benzo-12-crown-4)s
Authors: Maeda Takumi , Kimura Keiichi , Shono Toshiyuki 
Published: July 2006

Abstract
Solvent extractions of alkali metal picrates were carried out using newly synthesized poly- and bis(crown ether)s containing benzo-12-crown-4 moieties in a water-chloroform system. The extraction equilibrium constants(Ke) and the complexation constants (Kc) in the chloroform phase were determined at 25 °C. The Ke values for the alkali metal cations decreases as follows: Na+&gt;K+&gt;Rb+≥Cs+ with the poly(benzo-12-crown-4) and K+, Rb+, Cs+&gt;Na+ with the bis(benzo-12-crown-4). The poly(benzo-12-crown-4) improved the sodium-ion selectivity of the corresponding monocyclic analog because of the easy formation of 2:1 crown ether unit-cation complexes assisted by the cooperative action of two adjacent crown ether units, while the bis(benzo-12-crown-4) did not. A separate extraction experiment was also undertaken in a water-dichloromethane system in order to compare the extractability of these benzo-12-crown-4 derivatives with that of 12-crown-4.