Metal Complexes Of Type Research Articles

A trinuclear Cu(II) complex with functionalized s-heptazine N-ligands: molecular chemistry from a g-C3N4 fragment.

A new kind of N-ligand based on heptazine derivatives is presented. A trinuclear Cu(II) complex, [(L)2CuCl3](ClO4)3·3CH2Cl2 (L = 2,4,6-tris(di-2-pyridylamino)heptazine), utilizing a pyridine derivative of heptazine has been synthesized and characterized avoiding the inherent solubility problems of heptazine compounds. Thus, this work opens the application of such ligands either in supramolecular chemistry as a larger ligand of the widely used s-triazine derivatives or to provide molecular systems for photocatalysis as heptazine is the fundamental unit of the very promising g-C3N4 2D compound.

Reactions of Pd and Pt complexes with molecular oxygen.

Knowledge of exactly how metal complexes react with molecular oxygen is still limited and this has hampered efforts to develop catalysts for oxidation reactions using O2 as the oxidant and/or oxygen-atom source. A better understanding of the reactions of different types of metal complexes with O2 will be of great utility in rational catalyst development. Reactions between molecular oxygen and Pd(0-II) and Pt(0-IV) complexes are reviewed here.

Crystal structures of low-melting ionic transition-metal complexes with N-alkylimidazole ligands

A series of ionic liquids with copper(II), nickel(II) or cobalt(II)-containing cations have been synthesised and characterised, where possible with single crystal X-ray diffraction. A number of N-methylimidazole (MeIm), N-ethylimidazole (EtIm), N-butylimidazole (BuIm) or N-hexylimidazole (HeIm) ligands are coordinated to the metal centres and bis(trifluoromethyl)sulfonyl imide (Tf2N) anions provide the charge balance. Two types of metal complexes have been analysed. One has the general formula [Cu(AlkIm)4][Tf2N]2 (AlkIm = MeIm, EtIm, BuIm and HeIm) and contains square planar copper(II) centres with longer interactions to oxygen atoms of bis(trifluoromethylsulfonyl)imide anions. The other type of metal complex has a metal : ligand ratio of 1 : 6, with composition [M(MeIm)6][Tf2N]2 (M = Cu, Ni, Co) and contains octahedral metal centres. The ionic liquids have low melting points and the change in melting points is discussed as a function of alkyl chain length on the imidazole ligand and as a function of the metal centre. The metal–ligand interactions and intermolecular interactions in the crystal structures are analysed and related to the properties of the metal complexes.

ChemInform Abstract: Use of Ultrasound in Coordination and Organometallic Chemistry

AbstractReview: 150 refs.

Redox‐Responsive Metallo‐Supramolecular Polymers and Gels Containing bis‐Terpyridine Appended Cyclam Ligand

AbstractSummary: Soluble coordination polymers and gels built from a polytopic ligand containing two terpyridine units linked by a azamacrocyclic group are presented. This system originally incorporates two different types of metal complexes in the same polymer chain which induces remarkable electrochromic properties and a rare redox triggered reversible sol‐gel transition.

Phosphorescent iridium(III) complexes with hetero (CˆN) ligands

In order to improve luminescence efficiency, it is necessary to design a phosphorescent material which is capable of transferring the excited energy without triplet–triplet (T–T) annihilation. For this purpose, new types of metal complexes were designed with different species of (C ˆN) ligands. Herein, Ir(ppy)2(piq), Ir(ppy)2(piq-F) and Ir(ppy)2(piq-CF3) were designed and prepared, where ppy, piq, piq-F and piq-CF3 represent 2-phenylpyridine, 1-(phenyl)isoquinoline, 1-(4′-fluorophenyl)isoquinoline and 1-(4′-trifluoromethylphenyl)isoquinoline, respectively. These Ir(III) complexes having two different ligands (hetero-Ir complexes) are expected to have a high luminescence efficiency by intramolecular energy transfer from the energy absorbing ligand to the luminescent ligand leading to a decrease in quenching or energy deactivation. To compare luminescent characteristics of these hetero-Ir complexes, homo-Ir complexes Ir(ppy)3, Ir(piq)3, Ir(piq-F)3 and Ir(piq-CF3)3 were prepared and investigated photophysically.

Competitive Coordination of 2-[(Diorganylphosphinoyl)-hydroxymethyl)]-1-organylimidazoles with Metal Chlorides

The structure of complexes of bivalent cobalt, copper, zinc, cadmium, and palladium chloride and tetravalent tin chlorides with 1-organyl-2- [(diorganylphosphinoyl)hydroxymethyl]imidazoles, synthesized for the first time, was studied by 1H NMR and IR spectroscopy. The formation of two types of metal complexes, molecular (Zn, Cd, Pd, Sn) and chelate (Co, Cu), was established. For crystalline 1 : 1 complexes, the structures with imidazolylphosphine oxide playing the role of an N3,O-bidentate ligand were proposed. In 2L : 1 complexes, these ligands are monodentate and coordinate by the P=O oxygen atom. In DMSO solutions, the molecular complexes undergo dissociation to form coordination compounds in which, depending of the nature of the ligand, either M←N3 or M←O donor-acceptor bond takes place.

Pyridylthioethers: a promising class of polydentate ligands in palladium and platinum coordination

The role of bi- and ter-dentate pyridylthioether ligands in palladium and platinum coordination and organometallic chemistry is discussed. The binding ability of these ligands concerning the proton, copper and palladium is revisited. Moreover, the reactivity imparted by these ligands to several types of metal complexes in low and high oxidation states is examined. The complexes and the reactions explored are (i) allyl derivatives with respect to allyl amination (ii) olefin complexes and olefin exchange equilibrium reactions (iii) methyl derivatives and reactions of allene insertion. The synthesis of pyridylthioether-based dendrimers is also taken into account together with their solution behaviour when used as ancillary ligands in allyl metallo-dendrimer derivatives when the allylamination reactions are considered.

The synthesis and characterization of N-{2-[(1,4-dioxaspiro[4.5]- dec-2-ylmethyl)amino]ethyl}-N′-hydroxy-2-(hydroxyimino)ethanimidamide and some of its transition metal complexes

A new soluble vic-dioxime, N-{2-[(1,4-dioxaspiro[4.5]dec-2-ylmethyl)amino]ethyl}-N′-hydroxy-2-(hydroxyimino)ethanimidamide (LH2 ) has been synthesized and mononuclear complexes have been obtained with Co(II), Ni(II), Cu(II) and Zn(II) salts. Different types of metal complexes, such as [Co(LH)2(H2O)2], [M(LH)2] (M = Ni(II) and Cu(II)) and [Zn(LH)(Cl)(H2O)], were obtained. Co(II), Ni(II) and Cu(II) form complexes with LH2 which have a metal ligand ratio of 1 : 2. Zn(II) forms a complex with H2L which has a metal–ligand ratio of 1 : 1. Structures of these compounds were identified by using elemental analyses, IR, 1H and 13C NMR spectra, electronic spectra, magnetic susceptibility measurements, conductivity measurements and thermogravimetric analyses (TGA).

Fabrication and Electrical Properties of Dendrimer Langmuir-Blodgett Films Based on Metal Complex

We attempted to fabricate dendrimer Langmuir-Blodgett (LB) films containing a 48 pyridylpropoxy functional end group. The pyridylpropoxy functional group could form a complex structure with metal ions; in this study, the samples for the electrical measurement were fabricated using two types of metal complexes with Pt4+ and Fe2+ ions by the LB method. In addition, we investigated the surface activity at the air-water interface as well as the electrical properties of the mono layers of a pure G4-48PyP dendrimer and its complex with metal ions (Pt4+ and Fe2+ ions). In the surface pressure-area (π-A) isotherms of the dendrimers, the s table condensed films formed at the air-water interface and the metal ions effect showed a difference in molecular behavior. We also investigated the electrical properties of ultrathin dendrimer LB films by studying the current-voltage (I–V) characteristics of the metal/insulator/metal (MIM) structure. In conclusion, it is shown that the metal ion around the G4-48PyP dendrimer can contribute to the formation of the network structure of dendrimers, which results from the change in electrical properties.

Molecular Structure of Lead N-Octadecanoyl-l-alaninate Langmuir−Blodgett Film

Pb2+ ion exchange in N-octadecanoyl-l-alanine Langmuir−Blodgett film has been investigated by FTIR spectroscopy. The condensation effect of Pb2+ gives rise to a significant increase in the hydrogen-bonding interaction between adjacent molecules, so that a complete ion exchange occurs after Pb2+ penetrates into the Langmuir−Blodgett film through structure defects. FTIR studies demonstrate that two types of metal complexes are formed with different headgroup coordination and chain orientation: (1) the chelating bidentate complex is formed between Pb2+ ions and carboxylate groups, and the C−C−C planes of the corresponding hydocarbon chains are favorably oriented parallel to the film substrate; (2) the bridging bidentate complex is formed between Pb2+ ions and carboxylate groups, and the C−C−C planes are preferentially oriented perpendicular to the film substrate. The orthogonal orientation of the two types of C−C−C planes is considered to be the probable reason for the monolayer collapse in the presence of ...

SYNTHESIS AND SPECTRAL FEATURES OF Fe(III), Co(II), Ni(II), Cu(II), Zn(II), AND UO2(VI) COMPLEXES OF 3-FORMYL-4-HYDROXY-1,8- NAPHTHYRIDIN-2-ONE (OO) AND ITS ALDOXIME (ON)

The bidentate O, O donor ligand, 3-formyl-4-hydroxy-1, 8-naphthyridine-2-one, HL1, and its aldoxime derivative, an O,N donor ligand, HL2, were synthesized and used in chelating metal cations. The structures of the ligands were elucidated by IR and mass spectra. The mass spectra showed the molecular ion peaks at 190 and 205 a.m.u., respectively, corresponding to the formula weights of the ligands. Four types of metal complexes were prepared, [(L)2M(OH2)2].xH2O, [(L)2UO2(MeOH)] and [(L)2Zn]. xH2O [L = L1 or L2, M = Ni(II), Cu(II) and Co(II)], [(L2)2Fe (OH2)Cl].H2O and [L1Fe(OH2)2Cl2].2H2O. It was found that only one type of these metal complexes is obtained regardless whether the metal : ligand ratio was 1 : 1 or 1 : 2 and regardless of the metal salt used, chloride, acetate or perchlorate, except for the Fe(III) complex of HL1 which was formed using only the molar ratio 1 : 1. All complexes exhibted very similar IR features which indicate that the complexes are of similar structures. Electronic spectra and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared metal complexes. The Fe(III), Ni(II), Co(II) and Cu(II) complexes have octahedral geometry formed by the two aldehydic and two phenolate oxygen atoms in the case of complexes of the ligand HL1 and two oxime nitrogen atoms and two phenolate oxygen atoms in the case of complexes of the ligand HL2. In addition, chloride, water or methanol molecules are arranged in axial positions. A pentagonal-bipyramidal geometry for the UO2(VI) complexes and a square-planar geometry for the Zn(II) complexes are suggested.

Synthesis and Characterization of Metal Complexes of 4- Hydroxy-3-[2″-Hydroxyethylimino)Methyl]-2(1H)-1,8-Naphthyridinone, A Terdentate Ono Schiff Base Ligand

A terdentate ONO donor Schiff base ligand, H2L, was synthesized by the condensation of 3-formyl-l,8-naphthyridine-2-one with ethanolamine. The structure of the ligand was elucidated by IR and 1H NMR spectra indicating the presence of two different phenolic and alcoholic OH groups. The mass spectrum showed the presence of a molecular ion peak at 233 a.m.u. corresponding to the molecular weight of the ligand. Different types of metal complexes, [LM2(OH2)n]2 xH2O (M = Ni or Cu), [(HL)2M].xH2O (M˭Co or Ni), [LM2(OH2)nXm].xH2O (M = VO or Fe and X = S04 or CI) and [LM(OH2)Xm].xH2O(M = UO2 or Th, X = NO3), n, m and x are real numbers (0-8), were obtained. It was found that the type of the metal complex formed depends upon the metal ion as well as the metal: ligand ratio used except for Cu(II) which formed only one type of copper complex regardless whether the metal : ligand ratio was 1 : 1 or 1 : 2. Elemental analyses, IR and electronic spectra as well as conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared metal complexes. Square-pyramidal geometry is suggested for the VO(IV) and Cu(II) complexes, octahedral geometry for the Fe(III), Ni(II) and Co(II) complexes, a pentagonal-bipyramidal structure for the U02(VI) complex and a square-antiprismatic configuration of coordination number 8 for the Th(IV) complexes.

Magnetic, optical, and electrochemical properties of spin transition metal complexes

Two types of metal complexes were investigated Square planar platinum complexes, which are typical low spin complexes, have large third-order nonlinear susceptibility. Octahedral iron complex, which is typical high spin complex, does not exhibit nonlinear optical effect. Spectral changes of evaporated thin films of above complexes were carried out in the high magnetic field. MHD effect was found by chronoamperometric measurements of metal complex in the high magnetic field. The possibility of the fabrication of magneto-optical device, which is made from metal complexes, is discussed.

Investigation of metal–ion complexes of triazino crown ethers with podand arms by electrospray ionization

Double-armed triazino diaza crown ethers form stable complexes with alkali cations. In electrospray ionization [C2M]+ ions from 2:1 complexes appear additionally to the [CM]+ ions (C = crown ether ligand, M = metal). The portion of 2:1 complexes depends on the podand type. On collision-induced dissociation the [C1C2M]+ ions of asymmetrical 2:1 complexes form [CM]+ fragments with different intensities in correspondence to the complex stability. Triazino crown ethers with donor-active hydroxyalkyl podands give more stable 1:1 complexes with K+. However, this was only found in the larger of the two ring sizes compared. The electrospray ionization of solutions composed of Mg(II),Mn(II), Ni(II), Cu(II), Zn(II) or Mg(II) nitrates and triazino crown ethers generates four different types of metal complexes. However, the sum of all complex ions is only small compared to the total ion sum. Crown ethers without acidic hydrogen form [CM(II)NO3]+ ions. Hydroxyalkyl substituted triazino crown ethers produce [(C – H)M(II)]+ ions. With copper containing solutions of some crown ether types additionally [CCu(I)]+ are obtained at higher cone voltages. Only with Cd2+ doubly-charged complex ions like [CM(II)]2+ are found with significant intensities. In all cases the conventionally protonated molecule appears as the base peak in the ESI spectra.

A pump-probe method for the determination of Im of Ni(dmg)

Various types of metal complexes have received attention because of their large third-order nonlinear optical properties. Thin films of transition metal complexes with dionedioxime have been shown to form stacks perpendicular to the molecular plane, the central metal ions forming a quasi-one-dimensional chain of delocalized electrons. We have measured the imaginary part of the third-order nonlinear optical susceptibility, , of one such material, , by using the pump-probe method. We give a detailed derivation of the analysis of from the differential transmission data and present results near the lowest energy resonance of this material. Maximum values of the continuous wave susceptibility reached esu at resonance, with a relatively slow relaxation time of the order of 1 ns. The differential transmission crossed over from negative (saturation) to positive already on the low-energy side of the absorption band.

Platinum group metal complexes of arylphosphine ligands containing perfluoroalkyl ponytails; crystal structures of [RhCl2(η5-C5Me5){P(C6H4C6F13-4)3}] and cis- and trans-[PtCl2{P(C6H4C6F13-4)3}2

The triarylphosphine ligands PPh3–x(C6H4C6F13-4)x, x = 1, 2 or 3, reacted with [{RhCl2(η5-C5Me5)}2], [{RhCl(CO)2}2], [{IrCl(COD)}2], [PdCl2(MeCN)2] or [PtCl2(MeCN)2] to yield the complexes [RhCl2(η5-C5Me5)L] 1–3, trans-[RhCl(CO)L2] 4–6, trans-[IrCl(CO)L2] 7–9, trans-[PdCl2L2] 11–13 or cis-/trans-[PtCl2L2] 14–16 respectively. Spectroscopic studies and structural studies (EXAFS for 4–9, 11–15 and X-ray single crystal for 3 and 16) indicated that the aryl groups are fairly good insulators of the electronic influence of the perfluoroalkyl substituents whilst solubility studies indicated that at least six C6F13 units are necessary for preferential perfluorocarbon solvent solubility and that the type of metal complex is important, i.e. the Vaska’s analogues 6 and 9 are perfluorocarbon solvent soluble whereas the dichloride complexes 13 and 16 are not. Studies on the addition of dioxygen to 7–10 identified a stepwise reduction in rate following the introduction of the perfluoroalkyl ponytails.

Distinct metal binding configurations in ACE1.

The ACE1 protein of Saccharomyces cerevisiae mediates the metal-induced expression of the CUP1 metallothionein (MT) genes. Curiously, ACE1 resembles the MT protein in the types of metal complexes that form. ACE1 binds Cd(II) and Cu(I) ions in distinct configurations, but only the Cu(I) conformer of ACE1 forms a high-affinity and specific complex with DNA. Cu(I) ions associated with ACE1 are known to assemble in a polymetallic CuI-thiolate cluster that resembles Cu-metallothionein in metal coordination properties [Dameron, C. T., Winge, D. R., George, G. N., Sansone, M., Hu, S., & Hamer, D. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 6127-6131]. In contrast to the Cu(I) nuclearity of 6-7 mol equiv in ACE1 and 7 mol equiv in yeast MT, divalent ions, including Cd(II), Zn(II) and Co(II), bind with a maximal stoichiometry of near 4 mol equiv in ACE1 and 4 mol equiv in yeast MT. Charge-transfer bands consistent with metal:thiolate coordination were observed in CdACE1 and CoACE1. Spectroscopic studies of CoIIACE1 and EXAFS analysis of CdIIACE1 revealed tetrahedral coordination geometry in these complexes. Similar tetrahedral coordination complexes were observed with Co(II) and Cd(II) complexes of MT from S. cerevisiae. Metal binding in ACE1 is clearly similar to that in MT, and therefore the MT-metal clusters appear to be a good structural model of the metal center of ACE1.

修飾シクロデキストリンを配位子とした金属錯体の合成 ［Ｃｕ２（ｓａｌｅｎ２‐αＣＤ）］｀２＋´および［Ｆｅ（ｐｏｒ‐βＣＤ２）］｀＋´

An attempt was made to prepare two types of metal complexes with modified cyclodextrins, by which, these complexes were expected to exhibit an enzymatically catalytic effect. One was the binuclear Cu(II) complex with α-cyclodextrin, wherein two primary hydroxyl groups standing opposite to each other were replaced by N-salicylideneethylenediamine groups. The other was the Fe(III) complex with duplicate β-cyclodextrins with a porphyrin ring interposed between them. During the courses of preparation of those complexes, the crude products had to be purified by chromatography, because several by-products were formed.

ChemInform Abstract: COORDINATION OF ZWITTERIONIC 8‐QUINOLINOL (OXINE) TO MIXED OXINATE‐CARBOXYLATE COMPLEXES OF DIVALENT NICKEL, MANGANESE, AND MAGNESIUM

AbstractAus der Reaktion der Metalldioxinate mit Halogenessigsäuren in Benzol werden die Komplexe (I), (II) und (III) sowie ein zu (II) analoger Mg‐Komplex, der 4 Mol H2O enthält, isoliert und mit dem einfachen gemischten Chelat (IV) verglichen.