bluuebunny/crossref_metadata_2025_split huggingface dataset:
One-photon and Two-photon Electronic Spectra of Two Caged Amines
Authors: Gonohe Narishi , Yatsuda Norio , Mikami Naohiko , Ito Mitsuo 
Published: July 2006

Abstract
The one-photon fluorescence excitation and two-photon resonant multiphoton ionization spectra of the S1←S0 transition of 1,4-diazabicyclo[2.2.2]octane (DABCO) in a supersonic free jet have been obtained and analyzed. It was found from the vibrational analysis that the S1←S0 transition is one-photon forbidden, two-photon allowed and the one-photon absorption appears by the vibronic interaction between the S1 and S2 states through the e′ vibrations. In addition, from the fluorescence spectrum and the polarization studies of the two-photon spectrum using the two linearly polarized laser beams of different wavelengths, it was concluded that the S1 state is 1A1′. The sequence structure involving the low-frequency cage torsional vibration has been observed in the two-photon resonant multiphoton ionization spectra of DABCO and 1-azabicyclo[2.2.2]octane (ABCO). The potential functions with respect to the torsional motion for both ground and excited states have been determined by utilizing the observed vibrational levels. It was found that the torsional potential has a broad minimum near the D3h (for DABCO) and C3V (for ABCO) conformations.
Effect of 1,4-Dioxane on the Structure of Aqueous t-Butyl Alcohol. Sound Velocity Studies
Authors: Manohara Murthy Neriyanuri , Subrahmanyam Saraswatula Venkata 
Published: July 2006

Abstract
The structure of aqueous t-butyl alcohol in the water rich region is known to be more structured than pure water. 1,4-dioxane is known to be a weakly hydrophobic solute. The effect of 1,4-dioxane on the structure of aqueous t-butyl alcohol has been studied by fixing the temperature of sound velocity maximum in the ternary solution from the experimentally determined ultrasonic velocity data at different temperatures. The structural contribution to the shift in the temperature of sound velocity maximum of the aqueous t-butyl alcohol solution due to the addition of 1,4-dioxane, [ΔTstr.]exptl, has been found to be positive having the nature of variation similar to that of the effect of 1,4-dioxane on pure water, when the concentration (Xs) of t-butyl alcohol is 0.0075. But, for aqueous t-butyl alcohol solutions having Xs=0.0025 and Xs=0.0046, [ΔTstr.]exptl, has been found to be negative reaching maximum values around X2=0.0045 and there after decreasing with a tendency to become positive at higher concentrations of 1,4-dioxane. These results have been explained in the light of structure breaking and formation of dioxane complexes in the ternary solutions.
Observation of Spin Sublevel Excitation Spectra. An Application to Vibrational Analysis of T←S Absorption
Authors: Suga Kazuhiko , Nishi Nobuyuki , Kinoshita Minoru 
Published: July 2006

Abstract
A new application of the T1←S0 excitation spectroscopy is presented by which absorptions to one or two of the three spin sublevels can be measured separately. This method has been applied to the T1←S0 excitation of crystalline 1,2,4,5-tetrachlorobenzene and 9H-xanthen-9-one at 1.4 K. The vibrational structures of the excitation spectra are analyzed in view of the spin selectivity observed.
Spectrophotometric Determination of Hexacyanoferrate(III) by Use of Coagulated Material Prepared from Finely Divided Anion and Cation Exchange Resins
Authors: Suzuki Kin-ya , Park Guee-deuk , Ohzeki Kunio , Kambara Tomihito 
Published: July 2006

Abstract
A simple and sensitive method for the determination of hexacyanoferrate(III) is described. This method is based on the preconcentration of hexacyanoferrate(III) ion on the coagulated material prepared from finely divided anion and cation exchange resins. The mixed resin is collected on a filter paper, forming a disk of thin layer. The hexacyanoferrate(III) fixed on the resin is converted to Turnbull’s Blue by treating with iron(II) ammonium sulfate solution. The colored compound in the resin phase is determined by a densitometer equipped with a linearizer. The working range is 0.4–3.0 μmol dm−3 hexacyanoferrate(III). Among cations likely to be present, only copper(II) interferes, however, the interference is removed by the addition of EDTA. Hexacyanoferrate(II) ion shows the same coloration as hexacyanoferrate(III), and the total amount is determined when both ions are present.
Nitrosyliron Complexes Containing 8-Quinolinolate or Its Derivatives
Authors: Miki Eiichi , Motonaga Masaaki , Mizumachi Kunihiko , Ishimori Tatsujiro , Katada Motomi 
Published: July 2006

Abstract
New nitrosyls, [Fe(C9H6NO)2(NO)]2(C9H6NO−=8-quinolinolate ion), [Fe(C10H8NO)(NO)2] (C10H8NO−=2-Methyl-8-quinolinolate ion), and [Fe(C9H5NOCl)2(NO)(DMF)] (C9H5NOCl−=5-chloro-8-quinolinolate ion) were isolated by the reaction of nitrogen monoxide with a mixture of iron(II) perchlorate and the corresponding quinolinol in methanol or methanol/DMF. They were characterized by IR, 57Fe-Mössbauer, and magnetic measurements.
Copper(II) Complex of 2,2′-Bi-8-quinolinol
Authors: Demura Youichi , Hirakawa Kazuyoshi , Murase Ichiro 
Published: July 2006

Abstract
A copper(II) complex of 2,2′-bi-8-quinolinol was prepared. The structure has been determined by means of infrared and electronic spectra, magnetic susceptibility under temperature variation, and molecular weight measurement. It was found to be a binuclear chelate having a tetrahedral arrangement around each copper ion.
Studies of the Cobalt(III) Complexes of 8-Amino-3,6-diazaoctanate Ion. IV. Preparations and Some Properties of [Co(ADAO)XY] Type Complexes: XY=Cl(NH3), Cl(py), (H2O)(py), Cl(H2O), (NO2)(H2O), and Cl(NO2)
Authors: Watanabe Kiyokatsu 
Published: July 2006

Abstract
The following new cobalt(III) complexes containing the 8-amino-3,6-diazaoctanate ion (adao) have been isolated: two isomers of β-mer(N)-trans(Cl,Oada)-[Co(adao)(Cl)(NH3)]ClO4, two isomers of β-mer(N)-trans(Cl, Oadao)-[Co(adao)(Cl)(py)]ClO4, β-mer(N)-trans(O)-Co(adao)(H2O)(py)]ClO4·bcs, β-mer-(N)-trans(Cl,Oadao)-[Co(adao)(Cl)(H2O)]CLO4, β-fac(N)-[Co(adao)(Cl)(H2O)]ClO4, β-mer(N)-cis(O)-[Co(adao)(NO2)(H2O)]ClO4, and β-fac(N)-[Co(adao)(Cl)(NO2)]. The geometrical structures have been determined on the basis of the absorption spectra, the proton NMR spectra, and the consideration of their preparative processes.
Oxidative Synthesis, Optical Resolution, and Characterization of Mixed Sulfenato and Sulfinato Cobalt(III) Complexes
Authors: Kita Masakazu , Yamanari Kazuaki , Shimura Yoichi 
Published: July 2006

Abstract
Twelve new mixed sulfenato and sulfinato cobalt(III) complexes were prepared via successive H2O2 oxidation of [Co(SCH2CH2NH2)3], [Co{SCH2CH(COOCH3)NH2}3], and related complexes. These oxidation products, [Co(sulfenato-N,S)n(sulfinato-N,S)3−n] (n=3, 2, 1, and 0), were optically resolved by means of column chromatography or preferential crystallization of a diastereomeric molecular compound with d-tartaric acid. The mixed sulfenato and sulfinato complexes show characteristic variation of absorption spectra with the change of “n” in [Co(sulfenato-N,S)n(sulfinato-N,S)3−n] (n=3, 2, 1, and 0). It is concluded that the (R) configuration of the sulfenato group is more stable than the (S) one in the fac(S)-Λ-[Co(sulfenato-N,S)n(sulfinato-N,S)3−n].
Electron Transfer Activation in the Oxidative Addition of Iodine to Rhodium(I) Complexes
Authors: Fukuzumi Shunichi , Nishizawa Nobuaki , Tanaka Toshio 
Published: July 2006

Abstract
The kinetics of the oxidative addition of iodine to the following isocyaniderhodium(I) monomers and dimers in MeCN has been examined; [Rh(RNC)4]+, [Rh(RNC)2(PPh3)2]+, [Rh2(dppm)2(RNC)4]2+, and [Rh2(dicp)4]2+ (R=alkyl, aryl; dppm=bis(diphenylphosphino)methane; dicp=1,3-diisocyanopropane). The reaction proceeds via two consecutive steps which consist of the formation of the initial adduct followed by the intramolecular isomerization to yield the final trans-adduct. The kinetic results for the first step of the oxidative addition reactions suggest that there exist three kinds of intermediates formed between the Rh(I) complex and iodine with 1:1, 1:2, and 2:1 stoichiometry prior to the formation of the initial adduct. This mechanism coincides with that for the electron transfer reactions between the Rh(I) complexes and inorganic oxidants such as [Fe(N-N)3]3+ (N-N=1,10-phenanthroline and 2,2′-bipyridine). The values of the rate constants for the first step of the oxidative addition of iodine to dppm- or dicp-bridged Rh(I) dimers are found to agree with those for the electron transfer reactions between the same reactants by using linear free energy relationships. The possibility of electron transfer activation as the rate determining step in the oxidative addition to Rh(I) complexes is discussed.
Cyclic Voltammetry of Rh(I) Complexes and the Oligomers. A Correlation between the Anodic Peak Potentials and the Rate Constants for the Electron Transfer Reactions with Inorganic Oxidants
Authors: Fukuzumi Shunichi , Nishizawa Nobuaki , Tanaka Toshio 
Published: July 2006

Abstract
The cyclic voltammogram of a CH3CN solution of [Rh(p-MeOC6H4NC)4]+ exhibits three anodic current peaks which correspond to the oxidations of the monomer, the dimer, and the trimer, with no cathodic wave on the reverse scan. The anodic peak potentials Eoxp in such irreversible cyclic voltammograms were determined for various Rh(I) monomers and the oligomers such as [Rh(RNC)4]+, [Rh2(RNC)8]2+, [Rh2(dppm)2(RNC)4]2+, [Rh2(dicp)4]2+, [Rh3(RNC)12]3+, and [Rh4(dicp)8]4+ (R=p-MeOC6H4 and Ph, etc; dppm=bis(diphenylphosphino)methane, dicp=1,3-diisocyanopropane). The anodic peak potentials Eoxp vary mainly with the degree of oligomerization of the Rh(I) complexes, decreasing in the order monomer&gt;dimer&gt;trimer&gt;tetramer, in parallel with the energies of the highest occupied molecular orbitals EHOMO. It has been found that the Eoxp values are linearly correlated with logarithm of the rate constants for the electron transfer reactions with inorganic oxidants such as [Fe(bpy)3]3+ and [Co(bpy)3]3+ (bpy=2,2′-bipyridine) in the context of the Marcus theory as expected when the standard oxidation potentials Eoxo would be used. It is thus suggested that the anodic peak potentials of the Rh(I) complexes in the irreversible system can be used as the standard oxidation potentials as far as the relative values are concerned.
The Structure and Synthesis of Sudachiin A, a New Flavone Glucoside from Citrus Sudachi
Authors: Horie Tokunaru , Tsukayama Masao , Nakayama Mitsuru 
Published: July 2006

Abstract
Sudachiin A was isolated from the green peels of Citrus sudachi Hort. ex Shirai. This structure was deduced to be sudachitin 4′-β-d-glucoside by means of its spectra and degradation; this was confirmed by the synthesis of the one from sudachitin 7-benzyl ether and α-acetobromoglucose via several steps. 4′,5,7-Trihydroxy-3′,6,8-trimethoxyflavone 7-glucoside (sudachitin 7-β-d-glucoside), which was isolated from Sideritis leucantha Cavanilles, was also synthesized from sudachitin and α-acetobromoglucose in a similar manner.
Studies of the Selective O-Alkylation and Dealkylation of Flavonoids. V. The Synthesis of 5,6-Dihydroxy-3,4′,8-trimethoxyflavone and a Revised Structure for the Flavone from Conyza stricta
Authors: Horie Tokunaru , Kourai Hiroki , Osaka Hideaki , Nakayama Mitsuru 
Published: July 2006

Abstract
5,6-Dihydroxy-3,4′,8-trimethoxyflavone, which was the proposed structure of the pigment occuring in Conyza stricta, was synthesized from 2,3,5,6-tetramethoxyacetophenone in six steps. The natural pigment was identical not with the synthesized flavone, but with 5,7-dihydroxy-3,4′,8-trimethoxyflavone, an isomer of the former.
Photoinduced Ring-opening Reaction of 1-(2-Naphthoyl)aziridine in Various Halogenated Hydrocarbons
Authors: Nishimoto Sei-ichi , Izukawa Tsukuru , Kagiya Tsutomu 
Published: July 2006

Abstract
The in-source photoreaction and the postreaction of 1-(2-naphthoyl)aziridine (NAz) in various halogenated hydrocarbons have been investigated at room temperature under deaerated conditions. Secondary amide such as N-(2-chloroethyl)-2-naphthamide (CENA) or N-(2-bromoethyl)-2-naphthamide (BENA) was obtained along with a rearranged product of 2-(2-naphthyl)-2-oxazoline (NOz). The initial rate of secondary amide formation increased with decreasing dissociation energy of the carbon–halogen bond of halogenated hydrocarbon. The yield of CENA in the postreaction was substantially equal to that of chloride ion formed via the photolyses of chlorinated hydrocarbons. The rearranged product of NOz was confirmed to undergo subsequently photochemical ring-opening reaction to afford CENA or BENA.
Studies on Chemical Synthesis of mRNAs. I. Synthesis and Properties of N2-Tritylguanosine Derivatives and Application to Synthesis of pGpUpU
Authors: Hata Tsujiaki , Gokita Noboru , Sakairi Nobuo , Yamaguchi Kazuo , Sekine Mitsuo , Ishido Yoshiharu 
Published: July 2006

Abstract
Trityl (Tr), 4-methoxytrityl (MMTr), and 4,4′-dimethoxytrityl (DMTr) groups were introduced into the 2-amino group of 2′,3′,5′-tri-O-acetylguanosine by treatment with the corresponding trityl chlorides in pyridine to afford the N2-tritylated guanosine derivatives in high yields. Similarly, the N6-tritylated adenosine derivatives were synthesized. The stability of the three kinds of trityl groups under acidic conditions were described. The MMTr and Tr groups were found to be suitable for the protection of the 2-amino group of guanosine in oligonucleotide synthesis. An appropriately protected N2-tritylguanosine 5 -phosphorodithioate derivative was synthesized and utilized for the synthesis of pGpUpU.
Thermodynamic Properties for the Adduct Formation of Some Shift Reagents with Aniline
Authors: Kojima Hideo , Nonaka Hiroshi , Hirota Minoru 
Published: July 2006

Abstract
Equilibrium constants, enthalpies, and entropies of formation of the shift reagent-substrate adducts were determined by the measurement of infrared spectra. Aniline was employed as substrate in most cases since its NH stretching absorption bands (νas) does not overlap with those of the adducts and suitable to estimate the amount of its free species quantitatively. A series of Ln(dpm)3 and Ln(fod)3 (where Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Yb) were used as shift reagents. The formation constants (K1 and K2), as well as ΔH, decrease in the increasing order of the atomic numbers of the central lanthanoid ions. The results were compared with those on some bis(β-diketonato) complexes of transition metal ions and discussed.
Stereoselective α-Glucosylation with Tetra-O-benzyl-α-d-glucose and a Mixture of Trimethylsilyl Bromide, Cobalt(II) Bromide, Tetrabutylammonium Bromide, and a Molecular Sieve. A Synthesis of 3,6-Di-O-(α-d-glucopyranosyl)-d-glucose
Authors: Koto Shinkiti , Morishima Naohiko , Kusuhara Chiharu , Sekido Shigeko , Yoshida Toyosaku , Zen Shonosuke 
Published: July 2006

Abstract
A mixture of trimethylsilyl bromide, cobalt(II) bromide, tetrabutylammonium bromide, and a molecular sieve (4A) is effective for the stereoselective, one-stage α-glucosylation of alcohol with 2,3,4,6-tetra-O-benzyl-α-d-glucopyranose in dichloromethane. Using this procedure, several disaccharide derivatives as well as O-α-d-glucopyranosyl-(1→3)]-O-[α-d-glucopyranosyl-(1→6)]-d-glucopyranose are synthesized.
The Separation of Cobalt(II), Copper(II), Zinc(II), Lead(II), and Cadmium(II) as Their 3-Methyl-1-phenyl-4-thiobenzoyl-5-pyrazolone (SBMPP) Chelates by Thin-layer Chromatography on Silica Gel
Authors: Chouhan V S , Rao G N 
Published: July 2006

Abstract
Thin-layer chromatographic separation technique has been employed for the separation of Co(II), Ni(II), Cu(II), Zn(II), Pb(II), and Cd(II) as their 3-methyl-1-phenyl-4-thiobenzoyl-5-pyrazolone (SBMPP) chelates. Metal chelates are intensely coloured and so no additional reagent was needed for the development of spots. Silica gel G was used as an adsorbent in the form of thin layer coating (0.25 mm) on glass plates (5 cm × 20 cm). The Rf values of SBMPP and metal–SBMPP chelates have been determined by the ascending method with pure solvents and various binary solvent mixtures on thin layer of silica gel. In benzene the order of Rf values is Cd(II)&lt;Pb(II)&lt;Zn(II)&lt;Co(II)&lt;SBMPP&lt;Ni(II)=Cu(II). By employing solvents like dichloromethane, benzene, and toluene, mutual separation of metal complexes was achieved successfully. The mixed solvents are more useful for the mutual separation of chelates than the pure solvents.
Effect of Conformation on Ring Opening of Cis and Trans Dimers of Acenaphthylene in the Triplet State. Direct Detection of Hydrocarbon Biradical, 1,1′-Biacenaphthene-2,2′-diyl
Authors: Kobashi Harumichi , Ikawa Hiroki , Kondo Reiko , Morita Toshifumi 
Published: July 2006

Abstract
Triplet sensitized photodecomposition of cis and trans dimers of acenaphthylene (c-D and t-D) has been studied in benzene by means of a nanosecond laser flash photolysis. An aromatic hydrocarbon biradical, 1,1′-biacenaphthene-2,2′-diyl (1) was found as an intermediate for the decomposition of triplet t-D to acenaphthylene monomers. The rate of bond opening was directly measured to be 8.3×106 s−1 at 20 °C. The temperature dependence of the rate yields the frequency factor 2.8×107 s−1 and activation energy 3.1 kJ mol−1. The lifetime of 1 is 330 ns; this is insensitive to temperature changes (6–64 °C). Oxygen quenches 1 with the rate constant of 9×109 M−1 s−1 (1 M=1 mol dm−3). On the other hand, the triplet state of c-D did not show any evidence of the presence of 1 as an intermediate. The difference of ring opening mechanisms between the two isomers is interpreted in terms of different steric hindrances between two acenaphthene rings. The triplet-triplet (T-T) absorption spectra of both dimers resemble each other. No characteristic absorption due to intramolecular triplet excimer of naphthalene was observed even for c-D.
A New Synthesis of (Z)-13-Eicosen-10-one and (Z)-12-Nonadecen-9-one, the Pheromones of Peach Fruit Moth
Authors: Yoshida Takashi , Saito Shojiro 
Published: July 2006

Abstract
(Z)-13-Eicosen-10-one and (Z)-12-nonadecen-9-one were easily synthesized from starting 1-(p-tolysulfonyl)nonane and 1-(p-tolylsulfonyl)octane via 4 steps, respectively.
Studies on 2-Aziridinecarboxylic Acid. VI. Synthesis of β-Alkoxy-α-Amino Acids via Ring-opening Reaction of Aziridine
Authors: Nakajima Kiichiro , Neya Masahiro , Yamada Shinichi , Okawa Kenji 
Published: July 2006

Abstract
The reaction of aziridine derivatives having a urethane-type protecting group with several alcohols in the presence of boron trifluoride etherate afford the corresponding optically pure O-alkylserine and O-alkylthreonine derivatives via a ring-opening reaction of aziridine in good yield.
Radiation-induced Alkylation, Hydroxyalkylation, and Reduction of Pyridinecarboxamides in Acidic Alcoholic Solutions
Authors: Sugimori Akira , Nishijima Masayuki , Itoh Hiroshi 
Published: July 2006

Abstract
The γ-irradiation of pyridinecarboxamides in acidic methanol or ethanol brings about substitution of the ring hydrogen by alkyl or hydroxyalkyl groups derived from the solvent alcohols in relatively high G-values. In 2-propanol, little alkylation and hydroxyalkylation occur and reduction of CONH2 to CH2OH occurs in low G-values.
Study on the Reaction of Monofunctional Fluorescent Reagents in Organic Solutions by Fluorometry
Authors: Okamoto Akio , Uchiyama Katsumi , Mita Itaru 
Published: July 2006

Abstract
Rections of some fluorescent reagents with substrates, used widely in biochemistry for quantitative analysis of some functional groups in aqueous media, have been studied in organic solutions with a view that they may be used also in the area of synthetic polymer science. Reactions studied by fluorometry were (i) 5-dimethylamino-1-naphthalensulfonyl chloride with butylamine, (ii) 2-naphthalenesulfonyl chloride with butylamine, and (iii) N-(1-naphthyl)maleimide with 1-pentanethiol. In polar solvents all the fluorescent probes studied are too labile and converted spontaneously into fluorescent compounds. In less polar solvents, however, such side reactions do not take place and the reaction of fluorescent reagents with substrates proceeds quantitatively with a simple second-order kinetics. The second-order rate constants for the three reactions are of the order of 10−3 to 10−1 M−1 s−1 in the range of about 30 to 50 °C, and they increase with the solvent polarity.
A Molybdenum Polynuclear Complex as Small Metallic Particles
Authors: Okumura Hajime , Taga Tooru , Osaki Kenji , Tsujikawa Ikuji 
Published: July 2006

Abstract
The crystal structure of (H3O)2[(Mo6Cl8)Cl6]·6H2O was determined by the X-ray method and its near-infrared absorption spectra were measured. These results can be interpreted by a view that the molybdenum nuclei of this complex are regarded as a small metallic particle.
Despretz Constants for Individual Ions
Authors: Wakabayashi Toshiki , Takaizumi Katsuko 
Published: July 2006

Abstract
The shifts (ΔT) in the temperature of maximum density (tmd) of water produced by electrolytes have been revised. It was found that the temperature dependences of Sv and/or by bv coefficients in the Redlich-Meyer equation should be taken into account, to obtain exactly the Despretz constants (KD) or the standard partial molal expansibility (\barE°) from tmd data. The KD’s for 1 : 1 electrolytes were divided into the ionic components (KD,i), by applying the value for \barEi° (H+, 4 °C). Of the familiar monovalent ions, the KD,i values are negative (ΔT&gt;0) only for H+ and Li+ ions and are positive for all the anions examined, including F− ion. A further attempt was made to extract from KD,i’s for organic ions the structural part Kst,i’s, based on a model. The Kst,i’s seem to reflect the structure-influencing ability of organic ions, but may not always be the case.
Spectroscopic Study of 10-Benzoyl-9-anthrol and Its Anion in Basic Media. An Estimation of Microscopic Polarity of PMMA
Authors: Hamanoue Kumao , Hirayama Satoshi , Amano Masayuki , Nakajima Kazuo , Nakayama Toshihiro , Teranishi Hiroshi 
Published: July 2006

Abstract
The acid-base equilibrium of the title compound (BAOH) was studied in various media containing 4% triethylamine (TEA) by volume as a base. As the polarity of solvents increases, the equilibrium shifts toward the base form (BAO−) and 100% yield of BAO− is achieved in solvents with dielectric constant (ε) greater than 20. The equilibrium is also affected by temperature, favoring the base form at lower temperatures. The associated enthalpy change is estimated to be −14.6 kJ mol−1. Of particular interest is the dominant existence of BAO− in poly(methyl methacrylate) (PMMA), since the acid form (BAOH) dominates in a monomeric solvent (MMA). The microscopic effective dielectric constant of PMMA is estimated to correspond to that of a solvent with ε=22–30 by comparing spectral data in PMMA with those in various solvents. No base form is formed in polystyrene, indicating that not only rigidity but also polar groups in PMMA may be responsible for the anomalously large dielectric constant of PMMA.
Macromolecular Ion Flotation of Fe3+, Cu2+, and Ni2+ Ions by Combined Use of Macromolecular Anions and Cationic Surfactant
Authors: Sasaki Tsunetaka , Kud\={o} Takashi , Machida Ikuko , Ishiwata Satoshi 
Published: July 2006

Abstract
Macromolecular ion flotation of Fe3+, Cu2+, and Ni2+ ions was studied using macromolecular ions such as sodium metasilicate, sodium polyacrylate, sodium carboxymethylcellulose, sodium alginate, and sodium cyclo-hexaphosphate (SCHP) together with hexadecyltrimethylammonium chloride (HTAC). Diagrams of floatability vs. composition of macromolecular ion and HTAC, and floatability vs. pH at fixed composition of macromolecular ions and HTAC were constructed. Regions of optimum composition and pH for the flotation were determined and tabulated. Maximum floatabilities greater than 95%, some attaining nearly 100%, in the alkaline region were obtained for most of the systems, except for the system Fe3+–SCHP–HTAC which showed its maximum floatability, 91.7%, in the acid region. Metallic ions are considered to be combined as hydroxides with macromolecules which are then floated.