Three types of surfactants such as amphipathic crown ethers, poly (oxyethylene) types of nonionic surfactants, and terminal modified alcohol ethoxylates, which have a complexing ability with metal ions, are reviewed with 41 references.
This review describes the preparations and the properties of organic thin films by the controlled-potential electrolysis during the oxidation of an aqueous solution containing surfactants with a ferrocenyl moiety and organic compound incorporated in micelles (Scheme I) or dispersed organic particles using the surfactants (Scheme II).Films of azo dyes, 4, 4'-didodecylviologen and some polymers are prepared through Scheme I. Films of phthalocyanine compounds, MPc (M=H2, Cu, Mg, and AlCl), and halogen derivatives of CuPc, are prepared through Scheme II. The scanning electron micrograph studies show that crystal size of the film increases with electrolysis time in the case of Scheme I and is the same for the added particles in the case of Scheme II.
Compounds having chelating ligands and surface activity are reviewed. Hydrophobic groups were introduced into the chelate ligands such as ethylenediamine, polyethylene-polyimines, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), aminophosphonic acids, and 2-salicylic acid. Carbon - and nitrogen-substitution products or ester-and amide-derivatives of EDTA and DTPA were found to form metal chelates and have excellent surface activities. Some of them were applied to additives for coatings, coal slurry fuels and anti-tumor drugs.
The relationship between the nature of organic solvents and the extractability of metal complexes has been reviewed. The solvation of metal complexes in organic solvents, which is one of the most important factors to improve the extractability, has also been explained. In addition, recent topics such as adsorption of extractants and metal complexes on the liquid-liquid interface, and the oxidation of metal ions in complexes in organic solvents are described and the role of such phenomena on the solvent extraction of the metal is considered.
Chelating surfactants have been prepared and applied as ion-flotation collectors. Metal ions are floated by scum flotation using the surfactants in a HLB range of 4-14, which are regulated by varying the alkyl group. The selective flotation from the metal ions mixture has been attributable to the smaller HLB of the metal complexes. The HLB values of 16-24 are suitable for foam fractionation and those of 1-6 are for solvent sublation.
Zinc ion complexes constitute active sites of a number of zinc proteases like Carboxypeptidase A and Thermolysin. We have prepared a number of lipophilic imidazole ligands, having a hydroxyl function, for mimicking metalloenzymes. Cationic, anionic and non-ionic micellar systems are highly effective in the activation of ligand : metal ion complexes for ester hydrolyses. Ligand-metal ion (1 : 1 and/or 2 : 1 ratio) complexes are active catalysts via the dissociation of hydroxyl groups. Surfactant imidazole ligands were also examined. Related literatures are also briefly reviewed.
It is well known that nutritive organic substrates, such as proteins, carbohydrates and lipids etc ., are fairly reactive compounds whose reactions are very selective. Therefore it seems interesting for us to investigate the catalytic reaction of metal complexes coordinated with nutritive organic substrates as a mimetic sample of enzymatic reaction. For one example, it is dealt with the transformation of carbohydrate by utilizing nickel complexes with various polyamines and counter anions. Important informations are as follows. Aldoses were rapidly epimerized at C-2 by nickel (II) -diamine complexes. Recently we studied this reaction under various conditions, which are ligands, anions, reaction temperature and the molar ratio of ligand to metal ion.
Rh (III) porphyrins having 2-hydroxynaphthyl or 8-quinolyl groups at the 5-and 15-meso positions exhibit novel bifunctional cooperation of the central Rh (III) ion and the naphthol hydroxyl or quinolyl nitrogen. Thus, ketones undergo a facile enolization as a result of acidbase type cooperation. Amides, on the other hand, undergo a facile acyl substitution in the presence of Ag+ ions, as effected by a double Lewis-acid catalysis. The bis (hydroxynaphthyl) system also fixes amino acids and esters via simultaneous two-point interacion involving the Rh (III) -NH2-coordination and OH-CO2R hydrogen bonding (R=H or CH3). Some other examples of related multi-point molecular recognition using modified porphyrin systems are also presented.
Molecular oxygen coordinates to modified metalloporphyrin complexes selectively, rapidly and reversibly. Flexible membranes are prepared by combining these metalloporphyrin complexes with polymers. The complex residues maintain their oxygen-coordinating capability even after the fixation in the solid state membrane. Oxygen permeation through the membrane is facilitated due to the reversible and rapid oxygen-coordination to the fixed complexes and is in accordance with a dual-mode transport model. The (oxygen/nitrogen) permselectivity is greater than 10 in the membrane composed of cobaltporphyrin complexes with enhanced kinetic parameters.
Blue cotton is cotton bearing covalently linked blue pigment, copper phthalocyanine trisulfonate. Blue cotton can absorb polycyclic aromatic compounds selectively, and has been used extensively for isolating mutagens and carcinogens in the environment. This reviw providesa description of the present status of this method.
Ammonia is the only inorganic nitrogen molecule which can be metabolized by organisms. Most of higher plants and microorganisms which are not provided with the ability of N2 fixation, therefore, reduce NO3- and NO2- to NH3 (assimilatory reduction). On the other hand, some bacteria reduce those ions to N2 (dissimilatory reduction). Thus, the amounts of inorganic nitrogen molecules are regulated by nitrogen cycle, where molybdenum and iron atoms play key roles as the active center. This review describes chemical simulation of nitrogen cycle catalyzed by not only Mo complexes but also MoFeS and FeS clusters.
Free iron could easily be chelated with phosphate moiety in biomembrane surface and reduced enzymatically by certain membrane components or non enzymatically by ascorbate. A model membrane lipid peroxidation induced by iron-adriamycin or iron-glycated peptide was discussed. Most probable active species for their lipid peroxidations could be iron oxygen complexes, such as FeV= O and Fe IV=O type compounds. Heme-compounds, hemoglobin, cytochrome P-450 and hematin could mainly act to decompose lipid hydroperoxides to their corresponding alkoxy radicals and hydroperoxy radicals, by which lipid peroxidation should be promoted.
Vanadium distributes widely in litoshere, hydropere and biosphere. In mammalian tissues, vanadium is present at concentrations of 10 μ M or less, and this metal ion is proposed to be an essential trace element. Numerous physiological roles of vanadium have been reported at in vitro andin vivo levels. Since the finding that vanadate (+5 oxidation state of this metal) is a potent inhibitor of the sodium pump (Na+, K+-ATPase), the effects of vanadium have been explained in terms of its biochemistry. In this review the short history of the investigations, the chemistry, the metabolism, the physiological roles and the pharmacological effects of vanadium along with the vanadium-containing proteins and natural products are described.
Development of functional materials by taking advantage of properties of organometallic compounds is discussed in this article. Metals, metal oxides, and multimetal oxides are prepared by the CDL (chemical deposition in liquid phase) method by using liberation of ligands, reductive elimination, and complexation reactions of organometallic compounds. This method is applied for metal coating of carbon fibers. The advantages of metal coating using organometallic compounds by the CDL method over conventional melted-metal coating method or the CVD method are discussed.
We have synthesized various kinds of mixed ligand complexes of Ni (II) and Cu (II) which contain N-alkylated ethylenediamine (diam) and β-diketonate (dik) : general formula M (dik) (diam) X, where X is an anion with or without coordination ability. These complexes and [Fe (CN) 2 (phen) 2] synthesized by Schilt show the characteristic solvatochromism in various organic solvents due to the donor and acceptor abilities of solvents. These complexes are classified into two types as a color indicator of the solvent polarity : (1) donor indicators, [Ni (dik) (diam)] X and [Cu (dik) (diam)] X where X is a no-coordinating anion, (2) acceptor indicators, [Cu (dik) (diam) X] with a coordinating monodentate anion and [Fe (CN) 2 (phen) 2].
An oxidized enzyme consists of an iron compound called heme and huge proteins. It plays the role on antidote against an invading poisonous substance in the body by activating oxygen in the blood. We have been studied on the model reaction of these enzymes using metallophthalocy-anine derivatives and their polymers. This type artificial enzymes act on substances with strong odor. A new type odor removers using these artificial enzyme by biomimetic effects have been described.
Recent studies on transition metal complexes having sulfur-containing ligands are reviewed. Thiophene formed stable π-complexes with transition metals such as Mn, Ru and Rh. Studies on reactivities of the thiophene complexes and of dinuclear molybdenum sulfide complexes revealed detailed mechanism of heterogeneous hydrodesulfurization of organic sulfur compounds. Hexanuclear sulfide clusters of Mo and W, prepared by reductive coupling of trinuclear clusters, show similar structure to Chevrel compounds. Photolysis or thermolysis of thiolato complexes of Zn and Cd caused C-S bond cleavage in the thiolate ligands to give the corresponding metal sulfides.
A chemist-made asymmetric catalyst (“chemzyme”) for abiological transformations could be complementary to a god-made asymmetric catalyst (enzyme) for biological transformations. Thus, the development of asymmetric catalysis for abiogenetic-type reactions, carbon-carbon bond formations in particular, is the most challenging and formidable endeavor for synthetic organic chemists. Described herein is the development of the chiral titanium catalyst, prepared in the presence of molecular sieves (MS 4 A), for the enantiocontrol in carbonyl-ene reactions. The specific role of MS (zeolite), “positive” nonlinear effect, and the asymmetric catalyst-based diastereocontrol (double asymmetric induction and kinetic resolution) are also detailed.
Asymmetric aldol reaction of α-isocyanocarboxylates with aldehydes was catalyzed by gold- (I) complex coordinated with a chiral ferrocenylphosphine ligand containing (dialkylaminoethyl) amino group on the ferrocene side chain, which gave optically active (up to 98% ee) 5-alkyl-trans-4-methoxycarbonyl-2-oxazolines with high enantio-and diastereoselectivity in a quantitative yield. The optically active oxazolines were readily converted into β-hydroxy-α-amino acids and their derivatives.
The utility of chiral Lewis acid catalysts in organic synthesis has been increasingly important in recent years. This review describes how we have succeeded to design a new, chiral organoaluminum reagent as a chiral Lewis acid catalyst in the asymmetric hetero-Diels-Alder reaction of siloxydienes and aldehydes. Based on our conceptually new enantioselective activation of carbonyl moieties, exceptionally bulky, chiral organoaluminum reagents of type (R) -4 and (S) -4 can be successfully synthesized in optically pure forms from trimethylaluminium and (R) - (+) - or (S) - (-) -3, 3'-bis (triarylsilyl) binaphthol, respectively.
Epoxide and vicinal diol can be converted under mild conditions into manifold functionalities and, therefore, have been wildly used as intermediary functionalities in organic synthesis. Although various methodologies for the introduction of these oxygen functionalities have been developed, oxidation of olefinic double bond is most practical from the viewpoint of easy availability of olefinic compounds and mildness of the reaction. In this article, recent development in asymmetric transition-metal catalyzed epoxidation and dihydroxylation is described.
Asymmetric catalytic hydrogenation and hydrogen transfer reactions of various functionalized olefins and ketones by use of BINAP-Ru (II) and BINAP-Rh (I) complexes have been reviewed. These asymmetric transformations have provided us new efficient routes to a variety of optically active organic compounds with important biological activity. Recent advances in the related field have been briefly summarized.
This paper describes syntheses of highly coordinate organosilicon compounds and their application to regio-, stereo- and chemoselective organic synthesis which are recently developed. Topics are (1) the role of highly coordinate silyl intermediates on the reaction of organosilicon compounds with nucleophiles, (2) electrophilic cleavage of silicon-carbon bond and its application to functional group transformation, (3) preparations of pentacoordinate allylsiliconates as useful and storable reagents for regio-, chemo-, and stereoselective allylations of carbonyl compounds, which are interpreted by a six-membered cyclic transition state, (4) cross-coupling reactions of highly coordinate organosiliconates with organic iodides and triflates catalyzed by a palladium complex, and finally (5) chemo-and stereoselective, and asymmetric reductions of carbonyl compounds using hydridosiliconates.
Recent progress of our research about organocopper-Lewis acid complexes is summarized. The reaction of cyanocopper-boron trifluoride complexes with γ-mesyloxy-α, β-unsaturated esters gives α-alkylated-β, γ-unsaturated esters with very high 1, 3-chiral transfer (>99 : 1). In contrast, the reaction of γ-benzyloxy-α, β-unsaturated esters with various organocopper reagents proceeds in a 1, 4-addition manner to give the β-alkylated product. The diastereoselec-tivity is controlled by geometry of the carbon-carbon double bond. The diastereoselectivity in the reaction of γ-alkyl-α, β-unsaturated esters and related Michael acceptors highly depends upon the types of copper reagents. The syn-diastereoselectivity is observed with reagents which possess relatively high oxidation potential;cuprates or higher order cuprates produce the syn-diastereoselectivity. The anti-diastereoselectivity, which is expected from an ordinary Felkin-Anh model, is observed with the reagents having lower oxidation potential.
Electroorganic reactions using transition metal complexes attract much attention due to their unique high selectivities. This review is organized under the following headings. 1 Introduction 2 Indirect Electroorganic Reactions Using Transition Metal Complexes 2·1 Co-Complexes 2·2 Ni-Complexes 2·3 Pd-Complexes 2·4 Cu-Complexes 2·5 Zn-Complexes 2·6 Fe (CO) 5-Complex 2·7 Mn-Porphyrin Complexes 2·8 Hg-Complexes 3 Direct Electrolytic Reactions of Transition Metal Complexes 4 Concluding Remarks
The numerous improvements for the Ziegler-Natta catalysts have led to the development of MgCl2-supported catalysts modified by Lewis bases endowed with high activity and stereospecificity. The homogeneous catalytic systems composed of cyclopentadienyl derivatives of transition metals and cyclic oligomers of methylaluminoxane have been recently found to be capable of polymerizing olefins with extremely high yields. This paper describes some of the most significant aspects regarding the polymerization and copolymerization of olefins over these catalytic systems.
The present paper describes novel strategy for control of synthetic reactions by metalloporphyrins. Aluminum porphyrins have been found to be very effective initiators for living polymerizations of a wide variety of monomers to give polymers of uniform, controlled molecular weight. A novel concept, “immortal polymerization” has been established, which is of much use for elaborate molecular design of polymer materials. Photochemical fixations of carbon dioxide as a CI source for organic syntheses have been also achieved by using aluminum porphyrins. A highly stereoselective reaction has been observed in the reduction of ketones with alcohols catalyzed by a chloroaluminum porphyrin with Lewis acid character. Zinc N-substituted porphyrins as initiators have provided the first example of photo-induced living polymerization of epoxides. Novel chiral porphyrins and metalloporphyrins with molecular asymmetry have been synthesized and resolved.