Search

We have succeeded in synthesizing macroscopically aligned helical polyacetylene (H-PA) by using magnetically oriented chiral nematic liquid crystal (N*-LC) with monodomain structure. The N*-LC with...

We have synthesized two types of novel chiral compounds, D-1 and D-2−D-5, where D-1 is an asymmetric center-containing chiral compound of (S)-configuration, and D-2−D-5 are so-called double chiral compounds consisting of axially chiral binaphthyl moiety of (S)-configuration and asymmetric center moieties of (S)-, (S)-, (R)- and racemic configuration, linked with methylene spacers of 6, 12, 12 and 12, respectively. These chiral compounds were adopted as chiral dopants to induce chiral nematic liquid crystals (N*-LCs). The N*-LC including the double chiral dopant D-3, abbreviated as N*-LC with D-3 (system 2), showed an extraordinary increase in helical pitch (decrease in helical twisting power) in polarizing optical microscope (POM) when the temperature increased from 0 to 30 °C. This is due to a substantial cancellation in twisting power between the double chiral moieties having opposite screw directions, although both of them have the same (S)-configuration. Meanwhile, the N*-LC including the two types of...

Amphiphilic zinc chlorins possessing a 3 1 -hydroxy group were prepared. Non-ionic (oligo)oxyethylene group, anionic sulfonate and cationic quaternary ammonium groups were introduced on the 17-position of a zinc chlorin moiety. All the three kinds of amphiphilic chlorophyll derivatives self-assembled in an aqueous medium to favor a formation of the anti-parallel dimeric structure. In contrast, the amphiphilic zinc chlorins formed large aggregates in non-polar organic solvent. These studies showed self-assemblies of amphiphilic zinc chlorin chromophores were controlled in environments.

The dichloromanganese(IV) complexes with various bidentate and tetradentate Schiff base ligands, MnIV(L′)2Cl2 and MnIV(L)Cl2 have been obtained by the reactions of chloromanganese(III) complexes, MnIII(L′)2Cl and MnIII(L)Cl with hydrogen chloride or by the reactions of acetatomanganese(III) complexes, MnIII(L′)2OAc, with chlorine as deep green crystals, where L′H denotes bidentate Schiff base ligands N-R-salH (N-alkyl-salicylideneamine) and R can be n-C3H7, n-C6H13, n-C8H17, or n-C12H25, and LH2 denotes tetradentate Schiff base ligands X-salenH2 (N,N′-disubstituted-salicylideneethylenediamine) or X-salpnH2 (N,N′-disubstituted-salicylidenepropanediamine) and X can be H and 5-Br. X-ray structure analysis of the present dichloromanganese(IV) complexes has revealed that two chloride ions coordinate to the central manganese ion in a trans-form.

発色団を有する新規な大環状テトラアザシッフ塩基配位子L1並びにL2を合成し,銅(II)イオンとの錯形成条件を検討した.L1はL2に比較して,銅(II)イオンに対して高い選択性を示し,生成する錯体の安定性に優れ,高いモル吸光係数(loge=4.22)を有しているので,銅(II)イオンの定量試薬として流れ分析系に応用した.通常の並列流路方式とマージングゾーン法両方で検討した結果,前法では十分に錯形成が行われていないようで定量濃度域も低いが,後法では,最適条件下で得られた検量線の傾きが,バッチ法とほぼ同じであったことから,錯形成も十分であると考えられた。マージングゾーン法を用いることによりバッチ法とほぼ同等の精度で銅(II)イオンの定量が可能であり,又,バッチ法で大きく妨害したニッケル(II)イオンの影響が軽減された.

14-,18-, and 22-membered tetraaza macrocycles have been prepared by the reaction of acetylacetone with ethylenediamine, 1,4-butanediamine, or 1,6-hexanediamine, respectively. Their copper(II) and nickel(II) complexes were characterized by electronic and infrared spectroscopies. The 14-membered macrocycle forms a mononuclear copper(II) complex with a planar structure, whereas the 18-membered macrocycle forms a mononuclear copper(II) complex with a pseudo-tetrahedral structure, and the 22-membered macrocycle forms di- and trinuclear copper(II) complexes. The complexation and extraction abilities of these macrocycles toward copper(II) and nickel(II) ions are discussed.

Two new dicyanamide bridged complexes [Mn(μ1,5-dca)2(salicyh)2]n (1) and {[Ni(μ1,5-dca)(TTA)](ClO4)}n (2) (dca = dicyanamide, N(CN)2-; salicyh = salicylic hydrazide; TTA = triethylenetetramine) have been synthesised and structurally characterised. Both the compounds 1 and 2 consist in 1-D coordination polymers. In 1 the manganese atoms are doubly bridged by μ1,5-dca ligands, whereas in 2 the nickel atoms are bridged by a single μ1,5-dca ligand. The magnetic measurements indicate that whereas intrachain interactions take place between the metal ions for compound 1 (J = −0.26 cm−1), no evidence for any exchange coupling is found for compound 2.

Recently, high-valent manganese complexes have been investigated in connection with biological functions of manganese redox enzymes such as the manganese superoxide dismutase and the oxygen-evolving complex of photosystem II. We have studied on the reactions of a series of manganese(III) and (IV) Schiff base complexes with superoxide ion (O 2 - ) and water, respectively, in order to clarify the functions of these manganese co-factors. In the consecutive study, we have attempted to prepare novel high-valent manganese complexes.

Novel dinuclear manganese(III) complexes, MnIII2(N-PhO-sal)2(X-sal-m-xylylene) (X = H, 3-MeO) have been prepared by the ligand substitution reaction and characterized, where N-PhOH-salH and X-sal-m-xylyleneH2 denote N-2-hydroxyphenylsalicylideneamine and N,N′-di-substituted-salicylidene-m-xylylenediamine, respectively. These complexes have been found to decompose hydrogen peroxide catalytically (H2O2 /Mn < 100), cycling their oxidation levels between Mn2 (III,III) and Mn2 (II,II) with dioxygen evolution.

Four types of novel manganese complexes, MnIV (N-EtO-sal)2, MnIII(N-PhO-sal)(L), [MnIV(5,6-Benzo-L)2 (μ-O)2]2, and MnIII(L-4-Me)3 have been found to be obtained by the reactions of KMnO4 with tridentate Schiff base ligands (N-EtOH-salH, N-PhOH-salH and their derivatives) in dry MeCN, where N-EtOH-salH, N-PhOH-salH, LH, 5,6-Benzo-LH, and L-4-MeH denote N-2-hydroxyethyl-salicylideneamine, N-2-hydroxyphenyl-salicylideneamine, 2-(2-hydroxyphenyl)-benzoxazole, 2-(2-hydroxynaphthyl)-benzoxazole, and 2-(2-hydroxyphenyl)-5-methylbenzoxazole, respectively.

Novel di-μ-oxo dimanganese(IV) complexes, [MnIV(N-R-sal)2(μ-O)]2, with bidentate Schiff base ligands, N-alkyl-salicylideneamine, N-R-salH (R = n-C3H7 (Pr), n-C4H9 (Bu), n-C6H13 (Hx), n-C8H17 (Oct), n-C12H25 (Dod), or n-C18H37 (Octd)), have been prepared and characterized by spectroscopies, magnetic susceptibilities, thermal analysis and X-ray crystallography.

Novel di-μ-oxo dimanganese(IV) complexes with a series of tetradentate Schiff base ligands have been prepared and characterized by spectroscopy, magnetic susceptibility, electrochemical measurements and X-ray crystallography. The di-μ-oxo dimanganese(IV) complexes, [MnIV(μ-salophen)(μ-O)], 1 (salophen H2 = N,N′-disalicylidene-1,2-diaminobenzen), [Mn(μ-salen)(μ-O)]2, 2 (salenH2 = N,N′-disalicylidene-1,2-diaminoethane), [Mn(salen)(μ-O)]2, 3, [Mn(salipn)(μ-O)]2, 4 (salipnH2 = N,N′-disalicylidene-1,2-diaminopropane) and [Mn(salbn)(μ-O)]2, 5 (salbnH2 = N,N′-disalicylidene-1,4-diaminobutane), have been found to be obtained by the reaction of the tetradentate Schiff base ligands and potassium permanganate (KMnO4) in MeCN with stirring at room temperature. X-ray analysis revealed that these complexes are classified by two different types of di-μ-oxo manganese(IV) complexes in the coordination features of the liglands; one of them (1 and 2) has a structure in which salophen or salen ligands are coordinated to two manganese ions as a bridging bidentate ligand, whereas the other (3,4 and 5) has a structure in which salen, salipn or salbn ligands are coordinated to each manganese ion as a tetradentate ligand. These types were characterized from their IR spectra around 650 cm−1, UV-vis spectra and electrochemical properties.

The dichloromanganese (IV) complexes with bidentate Schiff bases derived from 3-nitrosalicylaldehyde with monoamines react with water to liberate molecular oxygen. This is confirmed by means of a spectrophotometry with alkaline pyrogallol solution and by using an oxygen electrode. The maximal liberation was observed at neutral pH range. The reaction products were identified to the corresponding manganese(II) complexes. These results suggest us that molecular oxygen is liberated as follows, 2MnIVL2Cl2 + 2H2O→ 2MnIIL2 + O2 + 4H+ + 4Cl−.

A novel polymer ligand (Poly-L) in which 6,8,15,17-tetramethyl-dibenzo-5,9,14,18-tetraazacyclotetradecene (L) is present as an integral part of the polymer backbone was synthesized and its solvent extraction of copper(II) and nickel(II) was investigated in comparison with L. The complexation reactions of Poly-L with the above metal ions were found to be much faster than those of L, with a high selectivity for copper(II).

A series of monomeric chloroiron(III) complexes with the quadridentate or quinquedentate Schiff bases such as N,N′-disalicylideneethylenediamine or bis[3-(salicylideneamino)propyl]amine react with superoxide ions, O2−, in dimethyl sulfoxide to give the corresponding μ-oxo dimers. The polymeric chloroiron(III) complexes with the polymeric (oligomeric) Schiff bases derived from 5,5′-methylenedisalicylaldehyde and triamines react with O2− in dimethyl sulfoxide to give the oxygenated complexes, probably dioxygen adducts, FeIII–O2−. This is suggested by the absorption spectra and the polarographic measurements.

The ethylenediamine adduct of bis(3-nitro-2,4-pentanedionato) copper (II) was prepared in ethanol, and characterized by spectroscopic and elemental analyses. The thermal reaction of the adduct in the solid phase resulted in the formation of a tetraaza macrocyclic copper(II) complex by the intramolecular condensation.

A facile synthetic route for unsymmetrical tetradentate Schiff-base ligands has been found by using 5-carboxysalicylaldehyde as a starting material, and their copper(II) and nickel(II) complexes have been prepared and characterized by magnetic susceptibilities, electronic absorption spectra, and polarographic reduction potentials.

The novel macrocyclic Schiff base ligands L1, L2 and L3 were prepared by the condensation of N,N′-bis(2-formyl-4-nitrophenyl)ethylenediamine with ethylenediamine, bis(3-aminopropyl)amine and N,N-bis(3-aminopropyl)methylamine, respectively, under high-dilution conditions. Their complexing abilities and extractabilities for transition-metal ions have been investigated and L2 has been found to be an excellent extractant for copper(II).

A novel tetraaza macrocyclic Schiff base ligand, 6,13-dinitro-5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,5,7,-12-tetraene, was prepared and its copper(II) and nickel(II) complexes were characterized. This ligand was found to be an excellent extractant for copper(II).

The novel polymeric ligand containing the tetraaza macrocycle as a pendant group was prepared by the reaction of 2,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,5,7,12-tetraene with iodomethylstyrene-divinylbenzene copolymer beads. The content of the ligand in the polymer was 0.75 mmol g −1 under the optimum conditions. The complexation of this polymer with copper(II) and nickel(II) in water under heterogeneous conditions in a batch system showed that it can bind copper(II) selectively by complex formation with the tetraaza macrocycle. The capacity for copper(II) was found to depend on the pH, ionic strength and ethanol content of the sample solutions. Moreover, the separation of nickel(II) and copper(II) was achieved in a column system.

The novel polymeric ligands, poly-(N 4 )H 2 ( I ) and poly-(N 4 )H 2 ( II ), in which the tetraaza macrocycle was present as an integral

The dichloromanganese(IV) Schiff-base complexes Mn(N-R-3-NO2 sal)2Cl2 (R = n-C3H7, n-C4H9, n-C6H13

18- and 22-membered tetraaza macrocycles were prepared from acetylacetone and 1,4-diaminobutane or 1,6-diaminohexane, respectively. Their copper(II) complexes were characterized by electronic spectroscopy and the copper(II) complex of the 18-membered macrocycle was found to be pseudo-tetrahedral.

18- and 22-membered tetraaza macrocycles were prepared from acetylacetone and 1,4-diaminobutane or 1,6-diaminohexane, respectively. Their copper(II) complexes were characterized by electronic spectroscopy and the copper(II) complex of the 18-membered macrocycle was found to be pseudo-tetrahedral.

The polymeric Mn(III) Schiff base complexes react with superoxide ions (O2−) in dimethyl sulfoxide (DMSO) to give the oxygenated complexes, while the corresponding monomeric Mn(III) complexes are reduced with O2− to the Mn(II) complexes.