Ethanol Ligands Research Articles

Bis(cinnamato-κO)bis[2-(dimethylamino)ethanol-κ2N,O]copper(II)

The Cu atom in the title complex, [Cu(C9H7O2)(C4H11NO)2], lies on an inversion centre in an octa­hedral geometry and is coordinated by two bidentate chelating 2-(dimethyl­amino)ethanol groups and two monodentate cinnamate groups which are mutually trans to each other. The non-coordinated O atoms of the cinnamate ligands form intra­molecular hydrogen bonds to the OH groups of the 2-(dimethyl­amino)ethanol ligands, generating six-membered rings.

{6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}(ethanol)dioxouranium(VI)

In the title compound, [UO2(C18H18N2O4)(C2H6O)], the U atom has a distorted penta­gonal–bipyramidal geometry with a tetra­dentate Schiff base and ethanol ligands in the equatorial plane and oxo atoms in the axial positions. Complex mol­ecules are connected by O—H⋯O and C—H⋯O inter­actions, forming dimers in the crystal structure.

Synthesis, characterization, thermal stability, reactivity, and antimicrobial properties of some novel lanthanide(III) complexes of 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene

Two series of new lanthanide(III) complexes of the type [Ln(HSAT)2(H2O)3Cl3] and [Ln(HSAT)2(NO3)3], where Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Tm, Yb, or Lu, and HSAT = 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene, are synthesized by the reaction of LnCl3 or Ln(NO3)3 with the title ligand in ethanol. The complexes are characterized by elemental analysis, magnetic moment values, molar conductivity, IR, UV-Vis, and 1H NMR spectral data. Two selected complexes are subject to thermogravimetric analysis, and their kinetic parameters are estimated using Coats-Redfern equation. The complex [La(HSAT)2(NO3)3] underwent facile transesterification when refluxed in methanol. The ligand and some selected complexes are screened for their antimicrobial properties. Antimicrobial activities of the ligand increase on coordination with the metal ion.

Electrocatalytic reduction of O2 at pyrolytic graphite electrode modified by a novel copper(II) complex with 2-[bis(2-aminoethyl)amino]ethanol and imidazole ligands

A new complex formed by Cu(II) with 2-[bis(2-aminoethyl)amino]ethanol and imidazole is prepared, and its electrochemical properties are studied. The electrochemical experiments are carried out in deaerated pH 7.0 buffer solution through cyclic voltammetry by scanning the potential from 0.1 to −0.5 V with this copper(II) complex-modified electrode as the working electrode. One redox process is observed, which could be assigned to Cu(II)/Cu(I). The formal potential E 0′ = (E pa + E pc)/2, where E pa and E pc are anodic and cathodic peak potentials, is −248 mV vs. SCE. A straight line, obtained from the plot of I pc vs. v, indicated a surface-controlled reaction. The modified electrode is very stable and exhibits catalytic activity for oxygen reduction. The possible mechanism for the catalytic reduction of oxygen is studied by cyclic voltammetry and chronoamperometry. The results show that the dioxygen is reduced via a pathway of four-electron reduction to form water. Chronoamperometric measurements show the potentiality of the use of this working electrode as an amperometric sensor for dissolved dioxygen in aqueous media.

Synthesis, characterization and bioactivity of mixed-ligand Cu(II) complexes containing Schiff bases derived from S-benzyldithiocarbazate and saccharinate ligand and the X-ray crystal structure of the copper-saccharinate complex containing S-benzyl-β- N-(acetylpyrid-2-yl)methylenedithiocarbazate

Mixed-ligand complexes of general formula, [Cu(NNS)(sac)] (NNS′ = S-benzyl-β- N-(2-acetylpyrid-2-yl)methylenedithiocarbazate, NNS″ = S-benzyl-β- N-(2-benzoylpyrid-2-yl)methylenedithiocarbazate and NNS‴ = S-benzyl-β- N-(6-methylpyrid-2-yl)methylenedithio-carbazate, sac = the saccharinate anion) have been synthesized by reacting [Cu(sac) 2(H 2O) 4] · 2H 2O with the appropriate ligands in ethanol and characterized by various physico-chemical techniques. Magnetic and spectral evidence indicate that the complexes are four-coordinate in which the Schiff bases coordinate as NNS ligands and the sac- anion coordinates as a unidentate N-donor ligand. An X-ray crystallographic structural analysis of [Cu(NNS′)(sac)] shows that the complex has a distorted square-planar geometry with the Schiff base coordinated to the copper (II) ion as a uninegatively charged tridentate chelating agent via the pyridine nitrogen atom, the azomethine nitrogen atom and the thiolate sulphur atom while the fourth coordination position is occupied by the N-bonded saccharinate anion. The complexes have been evaluated for their biological activities against selected pathogens and cancer cell lines. They display weak activity against the pathogenic bacteria and fungi. The complexes were highly active against the leukemic cell line (HL-60) but only [Cu(NNS′)(sac)] was found to exhibit strong cytotoxicity against the ovarian cancer cell line (Caov-3). All complexes were inactive against the breast cancer cell line (MCF-7).

Bis[2-(dimethylamino)ethanol-κ2 N,O](2,4-pentanedionato-κ2 O,O′)nickel(II) acetate

The Ni atom in the title complex, [Ni(C5H7O2)(C4H11NO)2](C2H3O2), has distorted octahedral coordination. The O atoms of the acetate ion are hydrogen bonded to the OH groups of the 2-(dimethylamino)ethanol ligands.

Preparation, characterization, two-photon absorption and optical limiting properties of a novel metal complex containing carbazole

Abstract The title complex, NiL2 · C6H6, has been successfully synthesized in good yield from reaction of a novel Schiff base ligand and nickel acetate in ethanol. The ligand (hereafter abbreviated as HL), derived from S-methyldithiocarbazate and N-ethyl-3-formylcarbazole, loses a proton from its tautomeric thiol form and coordinates to Ni(II) via the mercapto sulphur and β-nitrogen atoms upon complex formation. The structural, optical and physicochemical properties of the complex were characterized by X-ray diffraction, infrared spectroscopy, electronic spectra, thermal analyse and photoluminescence measurement. Single crystal X-ray diffraction analysis established that the geometry of Ni(II) is in a distorted square planar cis-configuration with two carbazole moieties on the same side and the two carbazole rings are almost parallel, forming a conjugated and electronic delocalization system. Two-photon absorption (TPA) coefficient β and cross-section of the complex were obtained by using the open aperture Z-scan technique. The optical limiting (OL) response was also measured.

Synthesis and structural charaterization of a Cu(II) complex with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDPT)

Reaction between Cu(II) perchlorate and 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDPT) ligand in ethanol produced [Cu(PDPT)2(ClO4)2]. This compound has been characterized by UV/VIS, IR and CHN analysis. The structure of [Cu(PDPT)2(ClO4)2] has been solved by X-ray crystallography. The coordination environment around the Cu(II) may be described as distorted octahedral in which two anions in the complex are coordinated, occupying trans positions.

Bis[2-(dimethylamino)ethanol-κ2N,O](pentane-2,4-dionato-κ2O,O′)nickel(II) chloride

The Ni atom in the title complex, [Ni(C5H7O2)(C4H11NO)2]Cl, is in a distorted octa­hedral coordination environment. Cations are linked into centrosymmetric dimers via O—H⋯Cl hydrogen bonds involving the OH groups of the 2-(dimethyl­amino)ethanol ligands and the Cl− anions.

Coordination of (aminoalkyloxymethyl)dimethylphosphine oxides with palladium(II). Crystal structure of trans-bis[2-(dimethylphosphinoylmethoxy-1,1-dimethylethylamine)]palladium(II) dichloride

The synthesis, structure and spectroscopic properties of novel palladium(II) chloro complexes with a series of (aminoalkyloxymethyl)dimethylphosphine oxides (AOPO) are reported. The complexes with general formula PdCl 2( N, N′-AOPO 2) were obtained by the reaction of PdCl 2(CH 3CN) 2 with the ligands in dry ethanol. The crystal structure of the trans-bis[2-(dimethylphosphinoylmethoxy-1,1-dimethylethylamine)]palladium(II) dichloride has been determined from single-crystal X-ray diffraction data. The compound crystallizes in monoclinic crystal system with P2 1/ n space group. The square-planar coordination sphere of palladium consists of two N atoms from two aminoalkyldimethylphosphine ligands and two Cl atoms in trans-arrangement. The AOPO ligand has monodentate coordination through the NH 2 group. The Pd–N and Pd–Cl distances are 2.0610(14) and 2.3225(4) Å, respectively. The preparation of complexes with a composition PdCl 2(AOPO) 2 in chloroform solution are also reported.

Time-Resolved Study of the Oxidation of Ethanol by Cerium(IV) Using Combined Quick-XANES, UV−Vis, and Raman Spectroscopies

Time-resolved X-ray absorption spectroscopy (Quick-XANES) has been combined with UV-vis and Raman spectroscopies to study the in situ reduction of Ce4+ to Ce3+ in ethanolic solution with a time resolution of ca. 4-5 s. For this purpose, a cam-driven oscillating double-crystal monochromator with a channel-cut crystal was combined with two spectrometers for UV-vis and Raman spectroscopies in a specialized cell which allows one to fit the optical pathways for all three spectroscopies individually. The results show that high-quality results can be obtained simultaneously, thus giving a detailed insight into the mechanisms of the investigated chemical reaction. The continuous release of nitrate and ethanol ligands from the initial Ce4+ into the solution finally leads to a trivalent cerium species which is only coordinated with water molecules after about 1800 s of reaction time.

Synthesis and characterisation of [[μ-(1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane)][(μ-(aquo)]bis[(acac)(ethanol)nickel(II)]] [BPh 4] 2

The pale blue title compound, 4, was obtained from the reaction between 1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane, Ni(acac) 2 and NaBPh 4 in aqueous acetone. X-ray structure determination at 120 K revealed that the dication of the ionic complex, 4, contains two independent octahedral Ni II centres with trans-Ni 2N 2O 4 chromophores. The macrocyclic ligand and an aqua ligand act as bridges to the two nickel centres: the Ni–O(aquo)–N bond angle is 137.65(17)°. Each Ni centre is bonded to two nitrogens of the macrocycle, to a chelating acac unit, to an ethanol molecule as well as the bridging oxygen of the aqua group. The two nickel atoms sit outside the macrocycle cavity, such that the macrocyclic ligand acts as a canopy for the remainder of the dication. While none of the macrocycle oxygens are involved in the coordination to Ni, they are involved in internal hydrogen bonding with the aqua and ethanol ligands. Magnetic measurements show a paramagnetic behaviour down to 2 K, with an effective moment of 2.8 Bohr magnetons at room temperature.

Synthesis, structure, and catalytic properties of V(IV), Mn(III), Mo(VI), and U(VI) complexes containing bidentate (N, O) oxazine and oxazoline ligands.

Synthesis of seven complexes containing oxazoline ([(L(1))(2)V=O] (4), [(L(1))(2)MoO(2)] (5), [(L(1))(2)UO(2)] (6); HL(1) (1) [HL(1) = 2-(4',4'-dimethyl-3'-4'-dihydroxazol-2'-yl)phenol]), chiral oxazoline ([(L(2))(2)UO(2)] (7); HL(2) (2) [HL(2) = (4'R)-2-(4'-ethyl-3'4'-dihyroxazol-2'-yl)phenol]), and oxazine ([(L(3))(2)V=O] (8), [(L(3))(2)Mn(CH(3)COO(-))] (9), [(L(3))(2)Co] (10); HL(3) (3) [HL(3) = 2-(5,6-dihydro-4H-1,3-oxazolinyl)phenol]) and their characterization by various techniques such as UV-vis, IR, and EPR spectroscopy, mass spectrometry, cyclic voltammetry, and elemental analysis are reported. The novel oxazine (3) and complexes 4, 5, 8 and 9 were also characterized by X-ray crystallography. Oxazine 3 crystallizes in the monoclinic system with the P2(1)/n space group, complexes 4 and 9 crystallize in the monoclinic system with the P2(1)/c space group, and complexes 5 and 8 crystallize in the orthorhombic system with the C222(1) space group and the P2(1)2(1)2(1) chiral space group, respectively. The representative synthetic procedure involves the reaction of metal acetate or acetylacetonate derivatives with corresponding ligand in ethanol. Addition of Mn(OAc)(2).4H(2)O to an ethanol solution of 3 gave the unexpected complex Mn(L(3))(2).(CH(3)COO(-)) (9) where the acetate group is coordinated with the metal center in a bidentate fashion. The catalytic activity of complexes 4-9 for oxidation of styrene with tert-butyl hydroperoxide was tested. In all cases, benzaldehyde formed exclusively as the oxidation product.

Organometallic aluminum compounds derived from 2-(1,3,5-dithiazinan-5-yl)ethanol ligands.

The reactions of AlMe(2)Y (Y = Me or Cl) with new ligands 2-(1,3,5-dithiazinan-5-yl)ethanol (1), 2-(1,3,5-dithiazinan-5-yl)-1-methylethanol (2), and 2-(1,3,5-dithiazinan-5-yl)-1-phenylethanol (3) are described. The ligands are coordinated to aluminum atoms by nitrogen and oxygen atoms, with a nitrogen based spiranic structure. Equimolar reactions gave dimeric structures bearing pentacoordinated aluminum atoms O-(AlMeY)-2-(1,3,5-dithiazinan-5-yl)ethanolates (4-7) as well as monometallic compounds with tetracoordinated aluminum atoms O-(AlMeY)-2-(1,3,5-dithiazinan-5-yl)ethanolates (8-9). Reactions with 2 equiv of the aluminum reagents afforded tetracoordinated dialuminum complexes O-(AlMeY)-O-(AlMe(2)Y)-2-(1,3,5-dithiazinan-5-yl)ethanolate (10-18). The structures of the new compounds were determined by NMR ((1)H,(13)C, and (27)Al) and complemented by X-ray diffraction of compounds 4, 10, and 16-18. Relevant intermolecular interactions C-H...S, C-H...Cl, and C-H...pi found in the crystalline network are reported.

Synthesis and Crystal Structure of Blue Luminescent Cadmium(II) Coordination Networks with 4,4′-Bis(imidazol-1-ylmethyl)biphenyl from Different Solvent Systems

Two supramolecular complexes, [Cd(bimb)2Cl2] (1) and [Cd(bimb)(DMF)Cl2]·DMF (2) [bimb=4,4′-bis(imidazol-1-ylmethyl)biphenyl], were synthesized by reactions of CdCl2·2.5H2O with bimb ligand in ethanol and N,N′-dimethylformamide (DMF), respectively, and their structures were determined by X-ray crystallography. Complex 1 is an infinite 2D grid network bridged by bimb ligands, and the 2D sheets were further linked by C–H ⃛Cl hydrogen bonds to form a polycatenated 3D framework. Complex 2 has dicadmium(II) di-μ-chloride units which are connected by bimb bridging ligands to form an infinite non-interpenetrating 2D network. The results provide a nice example of the solvent system exerting a great effect on the construction of supramolecular frameworks.

The Reactivity of an Iron(II)/Iron(III) System with Polyamine Ligands in Ethanol: An Electrochemical Study

AbstractThe pentadentate ligand picdien [LA; 1,9‐bis(2′‐pyridyl)‐2,5,8‐triazanonane)] and [Fe(DMSO)6](NO3)3 produce the hexacoordinate coordination compound [FeL′B]2+ after reaction in ethanol. This compound shows a change in the oxidation state of FeIII to FeII as well as an increase in the denticity of the starting ligand LA. The new ligand L′B {1,9‐bis(2′‐pyridyl)‐5‐[(ethoxy‐2′‐pyridyl)methyl]‐2,5,8‐triazanon‐1‐ene} has an imine carbon−nitrogen double bond. This study provides evidence for the nature of the intermediate species during the formation of [FeL′B](BPh4)2. A systematic study was performed based on the evolution of the voltammograms observed after the addition of ligand (LA, LB) or base (LiOEt) to FeIII, FeII solutions or stoichiometric metal‐ligand mixtures (LB is L′B without the imine group). The stability of FeLA3+ and FeLA2+ species in acidic media and under nitrogen atmosphere was confirmed. The reactivity of FeLB3+ and FeLA3+ systems was found to be very similar, and the reduction products were found to be FeII species with simultaneous ligand oxidation, which, in both cases, produces an imine double bond, giving rise to an intramolecular redox reaction. The following disproportionation equation describes the general form of this process: 2 FeL3+ ⇄ FeL2+ + FeL′2+ + 2 H+. The oxidation was verified by the double bond formation in LA and LB giving rise to L′A and L′B as can be seen in the general equation: R1−CH2−NH−R2 ⇄ R1−CH=N−R2 + 2 H+ + 2e−. The disproportionation reaction for FeLA3+ and FeLB3+ species depends on the acidity level of the media: this reaction cannot be verified in acidic media, while neutral and slightly basic media favour formation of the FeII species with L′A and L′B. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthesis and crystal structure of silver(I) carboxylate complexes, Ag(P nBu 3)[C(CH 3) 3COO] and Ag(Phen) 2[CF 3COO]·H 2O

Ag(P n Bu 3)[C(CH 3) 3COO] ( I) and Ag(Phen) 2[CF 3COO]·H 2O ( II) were synthesized by the reaction of silver (I) carboxylate with the neutral ligand in absolute ether and ethanol, respectively. Crystal structures of I and II were determined by single crystal X-ray diffraction. The crystal structure of I is built up from dimeric units in which two Ag(P n Bu 3)[C(CH 3) 3COO] molecules are linked by two AgO bonds (2.626 Å). The closest coordination environment of the silver atom consists of two oxygen atoms with average AgO distances of 2.38 Å and one phosphorous atom with a AgP distance of 2.326 Å. The crystal structure of II is formed by infinite rows of [Ag(Phen) 2] + cations between which [CF 3COO] − anions are arranged. Relations between volatility and crystal structures of I and II are discussed.

N-Heterocyclic Carbene Stabilized trans-Dihydrido Aqua and Ethanol Complexes of Ruthenium: Precursors to Complexes with Ru−Heteroatom Bonds

Attempts to isolate the bis-N-heterocyclic carbene complex Ru(AsPh3)(IMes)2(CO)H2 (IMes = bis(1,3-(2,4,6-trimethylphenyl)imidazol-2-ylidene)) by crystallization with either ethanol or hexane yields instead the ethanol and water complexes Ru(IMes)2(CO)(EtOH)H2 (1) and Ru(IMes)2(CO)(H2O)H2 (2), respectively. Both multinuclear NMR spectroscopy and X-ray crystallography demonstrate that these two compounds are isostructural with a trans arrangement of the hydride ligands. Thermolysis of 1 results in decarbonylation of the bound ethanol ligand to yield Ru(IMes)2(CO)2H2 (3). Substitution of the coordinated solvent ligands in 1 or 2 occurs readily with p-ethoxyphenol to give Ru(IMes)2(CO)(HOC6H4-p-OEt)H2 (4), while treatment of 2 with 1-propanethiol affords the thiol complex Ru(IMes)2(CO)(HSCH2CH2CH3)H2 (8). Reaction of 8 with CO gives the thiolate hydride species Ru(IMes)2(CO)2(SCH2CH2CH3)H (9), whereas addition of CO to either 1 or 2 affords Ru(IMes)2(CO)3 (5). The hydroxy hydride complex Ru(IMes)2(CO)2(OH)H (...

(Ethanol-O)nitro(α,β,γ,δ-tetraphenylporphyrinato)cobalt(III)

In the crystal structure of the title compound, [Co(NO2)(C44H28N4)(C2H6O)], a distorted octahedral CoIII complex shows orientational disorder such that the positions of the nitro and ethanol ligands are exchanged. As a result, the averaged structure has an inversion center at the Co atom.

Synthesis, structure, and reactivity of bis( N, N′-bis(2-hydroxybenzylidene)-2-hydroxyphenylmethanediaminato)zirconium(IV), a Schiff base complex with 6,4,6-membered chelate rings

The title complex Zr(dshpm) 2 has been successfully prepared by heating a 1:2 mole ratio of Zr(OBu n ) 4 and the free ligand in absolute ethanol. It is mononuclear and eight-coordinate in the solid state with a dodecahedral coordination sphere. The two O,N,N,O donor atom quadridentate Schiff base ligands each form 6,4,6-membered chelate rings. As expected, the change in a chelate ring sizes from 6,5,6- to 6,4,6- resulted in significantly more labile complex, as indicated by TLC and NMR of heated solutions and its subsequent chemical reactions. The 0.010 Å shorter average ZrN bond distance was not anticipated, and appears to result from the zirconium atom's preference that the oxygen atoms occupy certain locations. Preparations of two heteroleptic complexes from the title complex were undertaken to evaluate potential of the title compound as a synthon. A new fluorine-substituted homoleptic Schiff base Zr complex was also prepared, for comparison purposes. Despite the reasonable stability of Zr(dshpm) 2 in air, the decomposition of labilized Hdshpm(2-) ligand on silica gel and in heated solution interfered with the purifications of the desired heteroleptic products.