Synthesis and characterization of 5-(arylazo)thiobarbituric acids and their complexes

Summary S-(Arylazo)thiobarbituric acids and their complexes, derived from cobalt(II), nicke(II) and copper(II) were characterized by elemental analyses and spectral measurements. The¹H n.m.r. and i.r. spectra show the ligands to be in the keto-thione form. The strength of the intramolecular hydrogen-bonding is influenced by the electronic requirements of the aryl ring substituents.     

Synthesis, characterization of the luminescent lanthanide complexes with (Z)-4-(4-methoxyphenoxy)-4-oxobut-2-enoic acid

(Z)-4-(4-Methoxyphenoxy)-4-oxobut-2-enoic acid and its solid rare earth complexes LnL3.2H2O (Ln=La, Eu, Tb) were synthesized and characterized by means of MS, elemental analysis, FTIR, 13C NMR and TG-DTA. The IR and 13C NMR results show that the carboxylic groups in the complexes coordinated to the rare earth ions in the form of a bidentate ligand, but the ester carboxylic groups have not taken part in the coordination. The luminescence spectra of Eu(III) and Tb(III) complexes in solid state were also studied. The strong luminescence emitting peaks at 616nm for Eu(III) and 547nm for Tb(III) can be observed, which could be attributed to the ligand has an enhanced effect to the luminescence intensity of the Eu and Tb.     

Synthesis and characterization of diorganohydrazido(2-) tungsten complexes

Diorganohydrazido(2-) complexes of tungsten (L)Cl4W(NNR2) [R2=Me2, Ph2, -(CH2)5-; L=CH3CN, pyridine] were synthesized by reacting the corresponding 1,1-diorganohydrazine with WCl6, followed by reaction with acetonitrile or pyridine. Crystallographic structure determination of (CH3CN)Cl4W(NNMe2) and (CH3CN)Cl4W(NNPh2) allows a comparison of the structural features of the diorganohydrazido(2-) functionality with varying substituents. Mass spectrometry, thermogravimetric analysis, and preliminary chemical vapor deposition experiments were performed to determine the viability of these complexes as single-source precursors for deposition of WNx and WNxCy films.     

Synthesis and characterization of cerium,thorium, and uranyl complexes with ( E )-4-(4-methoxyphenoxy)-4- oxobut-2-enoic acid

(E)-4-(4-Methoxyphenoxy)-4-oxobut-2-enoic acid and its Ce(IV), Th(IV), and UO₂(II) complexes were synthesized and characterized by MS, elemental analysis, IR, UV, TG-DTA, and NMR. The complexes have composition [CeL₂(OH)₂ · 2H₂O] · H₂O, [ThL₂(OH)₂ · 2H₂O] · H₂O, and [UO₂L₂ · 2H₂O] · H₂O. Molar conductance data confirm that the three complexes are nonelectrolytes. The IR and NMR results show that the carboxylates coordinate to the metal ions bidentate, and the ester carboxylic groups do not take part in coordination. Luminescence spectra of the ligand and complexes in DMSO at room temperature were also studied showing strong luminescence of the metal ions.     

Synthesis and characterization of polymeric Ni(II) complexes of 4-(4-aminobenzyl)benzenamine (abba) and 4-(4-aminophenylthio)benzenamine (aptba) with thiocyanate

Two one-dimensional complexes, [Ni(SCN)₂(abba)₂] _n (abba?=?4-(4-aminobenzyl)benzenamine) (1) and [Ni(SCN)₂(aptba)₂] _n (aptba?=?4-(4-aminophenylthio)benzenamine) (2), were synthesized and characterized by EA, IR, X-ray crystallography and thermal analysis. The single crystal X-ray structural analyses of 1 and 2 show the complexes to be 1D chain polymers as a result of dibenzenamine (dba) bridging. Each Ni is six-coordinate and adopts a slightly distorted octahedral geometry with four N atoms from four dba ligands and two N atoms from two NCS-groups. Adjacent Ni atoms and two dba ligands form a 24-membered macrocycle. Thermogravimetric analysis and differential thermogravimetric analysis of 2 show that the thermal decomposition of 2 includes four transitions.     

Synthesis and characterization of thiosemicarbazone derivatives of 2-chloro-4-hydroxy-benzaldehyde and their rhenium(I) complexes

N-Thioamide thiosemicarbazone derived of 2-chloro-4-hydroxy-benzaldehyde (R = H, HL¹; R = Me, HL² and R = Ph, HL³) have been prepared and their reaction with fac-[ReX(CO)₃(CH₃CN)₂] (X = Br, Cl) in chloroform gave the adducts [ReX(CO)₃(HL)] (1a X = Cl, R = H; 1a′ X = Br, R = H; 1b X = Cl, R = CH₃; 1b′ X = Br, R = CH₃; 1c X = Cl, R = Ph; 1c′ X = Br, R = Ph) in good yield. Complexes 1a′ and 1b’ were also obtained by the reaction of HL¹ and HL³ with [ReBr(CO)₅] in toluene.All the compounds have been characterized by elemental analysis, mass spectrometry (FAB), IR and ¹H NMR spectroscopic methods. Moreover, the structures of HL², HL³ and 1a·H₂O were also established by X-ray diffraction. In 1a, the rhenium atom is coordinated by the sulphur and the azomethine nitrogen atoms, forming a five-membered chelate ring, as well as three carbonyl carbon and chloride atoms. The resulting coordination polyhedron can be described as a distorted octahedron.The study of the crystals obtained by slow evaporation of methanol and DMSO solutions of the adducts 1a′ and 1b, respectively, showed the formation of dimer structures based on rhenium(I) thiosemicarbazonates [Re₂(L¹)₂(CO)₆]·3H₂O (2a)·3H₂O and [Re₂(L²)₂(CO)₆]·(CH₃)₂SO (2b)·2(CH₃)₂SO. Amounts of these thiosemicarbazonate complexes [Re₂(L)₂(CO)₆] (2) were obtained by reaction of the corresponding free ligands with [ReCl(CO)₅] in dry toluene.In 2a·3H₂O and 2b·2(CH₃)₂SO the dimer structures are established by Re–S–Re bridges, where S is the thiolate sulphur from a N,S-bidentate thiosemicarbazonate ligand. In both structures the rhenium coordination sphere is similar; the dimers are in the same diamond Re₂S₂ face.     

反-4-(反-4'-正丙基环已基)环已醇的合成与表征

环己烷类液晶因具有高度的稳定性,较宽的相列相温区而受到人们的青睐。反-4-(反-4’-正丙基环己基)环己醇(trans-3HHE)是一种合成环己烷类液晶的重要中间体,它可通过酶选择性催化和顺式构型异构化二种方法合成。文献报道顺式构型异构化法是：4-(反-4’-正丙基环己基)苯酚以铑／碳或铑／氧化铝为催化剂,在酸性介质条件下进行加氢反应,     

Synthesis and characterization of binucleating bis(amidinate) ligands and their dialuminum complexes

Two general routes to binucleating bis(amidinate) ligands based on dibenzofuran and 9,9-dimethylxanthene backbones are reported. The free-base form of one of the ligands, (Ph,Mes)L(DBF)H(2), forms a 1:1 adduct with acetone. Single-crystal X-ray diffraction of this adduct reveals bidentate H-bonding of the bis(amidine) to the ketone oxygen. Bond lengths suggest that the individual H-bonds are relatively weak, yet IR spectroscopy shows a significant -26 cm(-1) shift for the carbonyl stretch relative to free acetone. Additionally, the new dialuminum complexes (i)(Pr)L(DBF)Al(2)Me(4) (3), (i)(Pr)L(Xan)Al(2)Me(4) (4), (t)(Bu,Et)L(DBF)Al(2)Me(4) (5), and (t)(Bu,Et)L(Xan)Al(2)Me(4) (6) are prepared by reaction of Al(2)Me(6) with the bis(amidines) in toluene solution. (1)H NMR spectroscopic studies indicate that 3 and 4 interact weakly with certain Lewis bases (DMSO, DMF, pyridine) to effect the exchange of the Al-bound Me groups. Other bases, such as THF and TMEDA, fail to interact. Solid-state structures for 3 and 4 are reported.     

Synthesis and characterization of some new mononuclear ruthenium complexes containing 4-(un)substituted dipyridylpyrazole ligands

A mononuclear ruthenium complex [Ru(bpy)₂(bpp)](PF₆) (1) and its halogenated and nitro derivatives [Ru(bpy)₂(Xbpp)](PF₆) (bpy = 2,2′-bipyridine; bpp = 3,5-bis(2-pyridyl)pyrazole; X = Cl, 2; X = Br, 3; X = I, 4; X = NO₂, 5) have been synthesized and characterized by ¹H NMR, ¹³C NMR, HRMS, elemental analysis. Complexes 2–5 have been further confirmed by X-ray diffraction. Their UV–Vis and emission spectroscopies, electrochemical measurements and acid–base properties are described. The results presented here reveal that the introduction of Cl, Br, I and NO₂ groups to the coordinated bpp⁻ ligand makes the absorption and emission maxima of the parent complex 1 blue-shifted, the oxidation potential of the Ru^II/Ru^III couple increased and the pK_a value decreased obviously. In addition, significant quenching of the emission by these groups is also observed.     

Synthesis of (E)-4-ethoxyphenyliminomethylaryls and their hydrochlorides

Condensation of p-phenetidine with the substituted aromatic benzaldehydes in methanol results in (E)-4-methylethoxyphenyliminoaryl derivatives. The latter react with gaseous hydrogen chloride in diethyl ether to form 4-ethoxymethylphenyliminoaryl hydrochlorides.     

Synthesis and characterization of N -(alky(aryl)carbamothioyl)cyclohexanecarboxamide derivatives and their Ni(II) and Cu(II) complexes

N-(R-carbamothioyl)cyclohexanecarboxamides (R: diethyl, di-n-propyl, di-n-butyl, diphenyl and morpholine-4) and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and NMR methods. N-(diethylcarbamothioyl)cyclohexanecarboxamide, HL¹, C₁₂H₂₂N₂OS, crystallizes in the orthorhombic space group P2₁2₁2₁, with Z = 4, and unit cell parameters, a = 6.6925(13) Å, b = 9.0457(18) Å, c = 22.728(5) Å. The conformation of the HL¹ molecule with respect to the thiocarbonyl and carbonyl moieties is twisted, as reflected by the torsion angles O1–C6–N2–C5, C6–N2–C5–N1 and S1–C5–N2–C6 of 1.68°, ?67.47° and 115.50°, respectively. The structure of HL¹ also shows a delocalization of the π electrons of the thiocarbonyl group over the C–N bonds. The ring puckering analysis shows that the cyclohexane ring has a chair conformation. The bis(N-(morpholine-4-carbonothioyl)cyclohexane carboxamido)nickel(II) complex, Ni(L⁵)₂, C₂₄H₃₈N₄NiO₄S₂, crystallizes in the monoclinic space group P2₁/c, with Z = 4, and unit cell parameters, a = 16.919(3) Å, b = 8.3659(17) Å, c = 19.654(4) Å, β = 107.43(3)°. Ni(L⁵)₂ is a cis-complex with a slightly distorted square-planar coordination of the central nickel by two oxygen and two sulfur atoms.     

Synthesis and photophysical characterization of 1- and 4-(purinyl)triazoles

Fluorescent adenine mimetics are useful tools for studying DNA, RNA and enzyme functions. Herein we describe the synthesis of eight 1-(purinyl)triazoles and two 4-(purinyl)triazoles utilizing the 1,4-regioselective copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction as the key step. The fluorescence properties of five of the synthesized 1-(purinyl)triazoles are also presented. The five measured compounds displayed low quantum yields. The results, when compared to previously published data, suggest a high influence of the substitution pattern of the triazole on the fluorescence properties.     

Synthesis and characterization of novel oxime-imine ligands and their heteronuclear ruthenium(III) complexes

Vicinal carbonyl oxime (HL¹) and oxime-imine (H₂L²) ligands and their mononuclear Ru(III) and Cu(II), heterodinuclear Ru(III)-Mn(II), Ru(III)-Ni(II), Ru(III)-Cu(II), and heterotrinuclear Ru(III)-Cu(II)-Ru(III) chelates were synthesized and characterized by elemental analysis, molar conductivity, IR, ESR, ICP-OES, magnetic moment measurements, and thermal analyses studies. The free ligands were also characterized by ¹H NMR spectra. The carbonyl-oxime ligand coordinates through the oxygen of =N-OH to form a six-membered chelate ring. The quadridentate tetraaza ligand (H₂L²) obtained by condensing of the bidentate ligand 1-p-diphenylmethane-2-hydroxyimino-2-(1-naphthylamino)-1-ethanone (HL¹) with 1,2-phenylenediamine coordinates with Ru(III) through its nitrogen donors in the equatorial position with the loss of one of the oxime protons and concomitant formation of an intramolecular hydrogen bond. Stoichiometric and spectral results of the metal complexes indicated that the metal: ligand ratios in the mononuclear complexes of the ligand (HL¹) were found to be 1: 2, while these ratios were 1: 1 in the mononuclear complexes of the ligand (H₂L²). The metal: ligand ratios of the dinuclear complexes were found to be 2: 1, and this ratio was 3: 2 in the trinuclear complex. The article is published in the original.     

2-(7-methyl-1H-benzoimidazol-2-yl)-6-(1-aryliminoethyl)pyridinylnickel complexes: Synthesis, characterization and their ethylene oligomerization

A series of 2-(methyl-substituted-1H-benzoimidazol-2-yl)-6-(1-aryliminoethyl)pyridines (L1–L6) were synthesized and used as N^N^N tridentate ligands for their nickel complexes (C1–C12). All ligands were fully characterized by elemental, NMR and IR spectroscopic analyses, while their nickel complexes were characterized by elemental and IR spectroscopic analyses. The single-crystal X-ray diffraction reveals that the complexes C1, C3 and C9 have distorted octahedral geometry around the Ni center. All nickel complexes, activated with Et₂AlCl, exhibit good catalytic activities toward ethylene oligomerization with major dimerization.     

Synthesis,characterization and antitumour activity of copper(II) 6-(4-chlorobenzylamino)purine complexes. X-ray structure of 6-(4-chloro-benzylamino)purinium perchlorate

Copper(II) complexes with 6-(4-chlorobenzylamino)purine (HL) have been prepared and characterized by elemental analysis, electronic, i.r., ES + mass and ¹³C-n.m.r. spectra, and by magnetic and conductivity data. Based on these physical methods, mainly the temperature dependence of magnetic susceptibility data, we conclude that the complexes are: [Cu₂(-Cl)₂(-HL)₂Cl₂] (1) and [CuCl₃(H⁺L)₂]Cl (2). They have been studied for their possible antitumour activity against human malignant melanoma G-361, human osteogenic sarcoma HOS, human chronic myelogenous leukaemia K-562 and human breast adenocarcinoma MCF7 cells in vitro. The IC₅₀ values were determined by calcein AM assay. The molecular structure of 6-(4-chlorobenzylamino)purinium perchlorate, i.e. a protonated form of the free HL ligand, has been determined by a single crystal X-ray analysis.     

Spectroscopic characterization of chloride and pseudohalide ruthenium(II) complexes with 4-(4-nitrobenzyl)pyridine

Chloride, isocyanate and isothiocyanate hydride carbonyl ruthenium(II) complexes of 4-(4-nitrobenzyl)pyridine were synthesized from the precursor complex [RuHCl(CO)(PPh₃)₃] and characterized by IR, NMR, UV–Vis spectroscopy and X-ray crystallography. The electronic structures of the complexes were investigated by means of DFT calculations, based on their crystal structures. The spin-allowed singlet–singlet electronic transitions of the complexes were calculated by time-dependent DFT, and the UV–Vis spectra are discussed on this basis. The emission properties of the complexes were studied at ambient temperature, and the quantum yields of fluorescence, the lifetimes and nature of the excited states are discussed. The chloride and isothiocyanate complexes are practically nonemissive, with quantum yields under 0.01 %. Interpretation of spectra, supported by TD-DFT calculations, indicates that in this energy region, the transitions have MLCT character with admixture of LLCT (chloride and isothiocyanate complexes). The dominant LLCT character was visible in the case of the most emissive (isocyanate) complex. The low values of the lifetimes and quantum yields for these complexes indicate the influence of the metal center in the emission process.     

Synthesis of polyfluoroalkyl-containing 1-(4-acetoxybutyl)- and 1-(4-hydroxybutyl)pyrazoles and their tuberculostatic activity

Alkylation of polyfluoroalkyl-containing pyrazoles with 4-bromobutyl acetate in acetone in the presence of potassium carbonate leads to a mixture of isomeric 1-(4-acetoxybutyl)-3-fluoroalkyl- and 1-(4-acetoxybutyl)-5-fluoroalkylpyrazoles, which in a number of cases were successfully separated by HPLC. Deacylation in acidic medium with gaseous hydrogen chloride and in basic medium with gaseous ammonia leads to 1-(4-hydroxybutyl)pyrazoles, which manifest moderate tuberculostatic activity.     

Synthesis and characterization of multimeric salicylaldimine thiosemicarbazones and their Pd(II) and Pt(II) complexes

A series of di- and trithiosemicarbazone ligands as well as their Pd(II) and Pt(II) 1,3,5-triaza-7-phosphaadamantane (PTA) complexes have been synthesised using templated reactions between various substituted salicylaldimine thiosemicarbazone ligands and metal precursors of the general formula cis-[M(PTA)₂Cl₂], where M = Pd or Pt. Characterization of these complexes was achieved using various analytical and spectroscopic techniques: elemental analysis, ESI-MS, FT-IR, and NMR (¹H, ¹³C{¹H} and ³¹P{¹H}) spectroscopy. The data revealed tridentate (O-N-S) coordination of the thiosemicarbazone moieties via the imine nitrogen, thiolato sulfur and phenolic oxygen to each metal center. In vitro biological evaluation of selected compounds was conducted against WHCO1 oesophageal cancer cells. Some of the multimeric compounds display some promising biological activity.     

Synthesis, structural characterization, and initial electroluminescent properties of bis-cycloiridiated complexes of 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine

A series of bis-cyclometalated Ir(III) complexes (8-10, 12, 15, 17, 19, 21, 23, 25, 28, 29 and 33) bearing two chromophoric N^∧C cyclometalated ligands derived from 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine (1) and a third nonchromophoric ligand has been synthesized. A palladium-catalyzed cross-coupling reaction between 2-chloro-4-methylpyridine (2) and 3,5-bis(trifluoromethyl)phenylboronic acid (3) was used to prepare 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine (1). Cyclometalation of (1) by IrCl₃ was carried out in (MeO)₃PO, with the formation of chloro-bridged dimer [N^∧C]₂Ir(μ-Cl)₂Ir[C^∧N]₂ (8). Reaction of (8) with lithium 2,4-pentanedionate, lithium 2,2,6,6-tetramethyl-heptane-3,5-dionate (13), dipivaloyltrimethylsilylphosphine (14), 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octadione (16), 1,1,1,3,3,3-hexafluoro-2-pyridin-2-yl-propan-2-ol (18), 1,1,1,3,3,3-hexafluoro-2-pyrazol-1-ylmethyl-propan-2-ol (20), 2-diphenylphosphanylethanol (22), and 1-diphenylphosphanylpropan-2-ol (24), afforded octahedral iridium complexes 9, 12, 15, 17, 19, 21, 23 and 25, respectively. Complex 10, which contains three different ligands (L₁ = N^∧C of 1; L₂ = N^∧C of 4,4′-dimethyl-[2,2′]bipyridinyl 4; L₃ = O^∧O of 2,4-pentanedione), and complex 11, which contains no cyclometalated ligands (L₁ = 4; L₂ = L₃ = Cl; L₄ = O^∧O of 2,4-pentanedione) were also isolated as minor products in a one-pot reaction between a 94:5 mixture of 1 and 4, IrCl₃ and lithium 2,4-pentanedionate. Reaction of 8 with diphenylphosphanylmethanol (27) in 1,2-dichloroethane unexpectedly led to complexes 28 and 29. The reactions of 8 with benzoylformic acid resulted in the formation of hydroxyl-bridged dimer [N^∧C]₂Ir(μ-OH)₂Ir[C^∧N]₂ (33). According to X-ray analyses, Ir-to-Ir distances in the crystal cell increase from 6.86 Å for 10 to 13.31 Å for 33. The angle theta, which represents the twisting of two cyclometalated C-Ir-N planes relative to each other, varies from 97.5° for 21 to 90.76 for complex 28. OLED devices were fabricated from several Ir complexes and preliminary results are discussed.