Search results for "O ligands"
showing 10 items of 13 documents
Titanium Complexes Stabilized by a Sulfur‐Bridged Chelating Bis(aryloxo) Ligand as Active Catalysts for Olefin Polymerization
2004
The mixed-ligand complexes [Ti2(μ-OR)2(OR)2(κ3-tbop)2] (1a) for R = Me and (1b) R = Et were prepared by the reaction of Ti(OR)4 and H2tbop {H2tbop = 2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol]} in methanol. Treatment of 1a and 1b with AlMe3 led to the substitution of terminal alkoxy groups to create the organometallic compounds [Ti2(μ-OR)2(κ3-tbop)2(Me)2] (2a) for R = Me and (2b) for R = Et. Controlled hydrolysis of 2b causes the evolution of methane and the formation of the titanoxane compounds [{Ti2(μ-OEt)2(κ3-tbop)2}2(μ-O)2]·2CH2Cl2 (3). Structures of 1a, 1b, 2a, 2b, and 3 were confirmed by NMR spectroscopy; 1b and 3 were further investigated with X-ray crystallography. Compounds 1a…
A Heterobimetallic Anionic 3,6-Connected 2D Coordination Polymer Based on Nitranilate as Ligand
2016
In order to synthesize new coordination polymers with original architectures and interesting magnetic properties, we used the nitranilate ligand (C₆O₄(NO₂)₂2- = C₆N₂O₈2-), derived from the dianionic ligand dhbq2- (2,5-dihydroxy-1,4-benzoquinone = H₂C₆O₄2-). The use of this bis-bidentate bridging ligand led to [(DAMS)₂{FeNa(C₆N₂O₈)₃}·CH₃CN]n (1) (DAMS⁺ = C16H17N₂⁺ = 4-[4-(dimethylamino)-α-styryl]-1-methylpyridinium), a 2D heterometallic coordination polymer presenting an unprecedented structure for any anilato-based compound. This structural type is a 3,6-connected 2D coordination polymer derived from the well-known honeycomb hexagonal structure, where Fe(III) ions alternate with Na⁺ dimers …
Slow Relaxation of the Magnetization in Anilato-Based Dy(III) 2D Lattices.
2021
The search for two- and three-dimensional materials with slow relaxation of the magnetization (single-ion magnets, SIM and single-molecule magnets, SMM) has become a very active area in recent years. Here we show how it is possible to prepare two-dimensional SIMs by combining Dy(III) with two different anilato-type ligands (dianions of the 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone: C6O4X22−, with X = H and Cl) in dimethyl sulfoxide (dmso). The two compounds prepared, formulated as: [Dy2(C6O4H2)3(dmso)2(H2O)2]·2dmso·18H2O (1) and [Dy2(C6O4Cl2)3(dmso)4]·2dmso·2H2O (2) show distorted hexagonal honeycomb layers with the solvent molecules (dmso and H2O) located in the interlayer space and…
High oxidation state aqueous organometallics: synthesis and structure of a dinuclear oxo(pentamethylcyclopentadienyl)acetato complex of molybdenum(IV…
2003
International audience; The zinc reduction of Cp*2Mo2O5 in a MeOH–H2O mixture in the presence of acetic acid affords the diamagnetic dinuclear compound [Cp*MoO(O2CCH3)]2. An X-ray structural investigation reveals a novel dioxo- and diacetato-bridged structure, with a relatively strong metal–metal bond [2.5524(3) Å]. The compound exhibits a reversible one-electron oxidation process in the cyclic voltammogram. A comparison with other related structures reveals the effect of the electric charge on the mononuclear or dinuclear structural choice.Zinc reduction of Cp*2Mo2O5 in water–methanol in the presence of acetic acid affords compound Cp*2Mo2O2(O2CCH3)2, whose dinuclar tetrabridged structure …
Amide functionalized aminobisphenolato MoO2 and WO2 complexes: Synthesis, characterization, and alkene epoxidation catalysis
2023
The use of dioxidomolybdenum(vi) and -tungsten(vi) complexes supported by a variety of structurally different tri- and tetradentate aminobisphenolato ligands as pre-catalysts in the epoxidation of alkenes is well established. However, under the widely used standard 1 mol-% catalyst loadings these types of complexes generally show modest activity only. Recently, amide functionalities in the ligand design of various aminomonophenolato MoO2 complexes have been shown to lead to heightened catalytic activity in alkene epoxidation. In this paper we show that similar ligand amide functionalization can lead to significant enhancement in the alkene epoxidation activity of aminobisphenolato MoO2 comp…
Enantioselective Synthesis of 4-Substituted Dihydrocoumarins through a Zinc Bis(hydroxyamide)-Catalyzed Conjugate Addition of Terminal Alkynes
2013
A new enantioselective catalyst for the conjugate addition of terminal alkynes has been developed. Terminal alkynes react with 3-alkoxycarbonylcoumarins in the presence of diethylzinc and bis(hydroxyamide) ligands to give chiral non-racemic dihydrocoumarins substituted with an alkynyl group on the C-4 position with good yields and enantiomeric excesses up to 95%.
Two new supramolecular architectures of singly phenoxo-bridged copper(II) and doubly phenoxo-bridged manganese(II) complexes derived from an unusual …
2009
International audience; Two new coordination complexes {[(L)Cu2('-L)(NO3)(CH3OH)0.3(H2O)0.7]·NO3}[Cu(L)(NO3)(CH3OH)] (1) and [Mn2(-L)2(H2O)(1-N3)2(CH3OH)] (2) derived from (E)-N-(2-hydroxy-3-methoxybenzylidene)acetohydrazide [LH] have been synthesized. The new potentially tetradentate ONOO donor hydrazone ligand [LH] has shown considerable metal ion selective phenoxo bridging in 1 and 2. It has coordinated copper(II) ions in its tridentate as well as in tetradentate fashion whereas for manganese(II) ions it solely showed its tetradentate character. In 1 the two adjacent pentacoordinate copper(II) centers are connected by a rare single phenoxo linkage of the hydrazone ligand whereas 2 is a d…
Bridgehead isomer effects in bis(phosphido)-bridged diiron hexacarbonyl proton reduction electrocatalysts
2017
The influence of the substitution, orientation and structure of the phosphido bridges in [Fe2(CO)6(μ-PR2)2] electrocatalysts of proton reduction has been studied. The isomers e,a-[Fe2(CO)6{μ-P(Ar)H}2] (1a(Ar): Ar = Ph, 2′-methoxy-1,1′-binaphthyl (bn′)), e,e-[Fe2(CO)6{μ-P(Ar)H}2] (1b(Ar): Ar = Ph, bn′) were isolated from reactions of iron pentacarbonyl and the corresponding primary phosphine, syntheses that also afforded the phosphinidene-capped tri-iron clusters, [Fe3(CO)9(μ-CO)(μ3-Pbn′)] (2) and [Fe3(CO)9(μ3-PAr)2] (3(Ar), Ar = Ph, bn′). A ferrocenyl (Fc)-substituted dimer [Fe2(CO)6{μ:μ′-1,2-(P(CH2Fc)CH2)2C6H4}] (4), in which the two phosphido bridges are linked by an o-xylyl group, was al…
Cyclopentadienylmolybdenum(VI) and molybdenum(V) oxo chemistry: New synthetic and structural features
2002
International audience; Convenient syntheses for Cp, Cp*, and related cyclopentadienyl derivatives (4Cp = C5HiPr4; Cp′′′ = C5H2tBu3-1,2,4) of formula [(Ring)2Mo2O5] are described. Compound [Cp2Mo2O5] was produced in good yields by the rapid oxidation of red [CpMoO2]4 with PhIO in CH2Cl2. [Cp*2Mo2O5] was obtained by CH3COOH acidification of aqueous solutions of [Cp*MoO3]−Na+, the latter being generated in a single step from [Cp*MoCl4] and more than 5 equiv. of aqueous NaOH in air. Minor quantities of [Cp*MoO2]2 were also isolated from this reaction, although the formation of this by-product may be reduced by using a two-step basic hydrolysis procedure. Extension of the latter strategy also a…
Slow Magnetic Relaxation in a Co (II)–Y (III) Single‐Ion Magnet with Positive Axial Zero‐Field Splitting
2013
This work was supported by the MINECO (Spain) (Project CTQ2011-24478), the Junta de Andalucía (FQM-195 and Project of excellence P08-FQM-03705), and the University of Granada. E.R. and E.Cr. thank MINECO grant No. CTQ2011-23862-C02-01 and Generalitat de Catalunya grant No. 2009SGR-1459, for financial support. We would like to thank Prof. Liviu Chibotaru for providing us the SINGLE_ANISO program and Dr. Andrew Ozarowski for the EPR simulation software. E.K.B. thanks the EPSRC and Leverhulme Trust for financial support. The NHMFL is funded by the NSF, DoE, and the state of Florida. J.C. acknowledges financial support by the Spanish Ministerio de Ciencia e Innovación through projects CTQ2010-1…