Synthesis of Eu（Ⅲ） and Tb（Ⅲ） Complexes with Two New Amide Type Podands and Their Luminescence Properties

Two new amide type podands L1 and L2 (L1=1,1,1-tris{[2-benzylaminoformyl)phenoxyl] methyl} propane,L2=1,3,5-timethyl-2,4,6-tris{[2-benzylaminoformyl)phenoxyl]methyl} benzene)and their europium and terbium nitrates complexes were synthesized.The luminescence properties of these complexes were also studied.     

Synthesis, structures, and luminescence properties of lanthanide complexes with structurally related new tetrapodal ligands featuring salicylamide pendant arms

To explore the relationships between the structures of ligands and their complexes, we have synthesized and characterized a series of lanthanide complexes with two structurally related ligands, 1,1,1,1-tetrakis{[(2'-(2-benzylaminoformyl))phenoxyl]methyl}methane (L(I)) and 1,1,1,1-tetrakis{[(2'-(2-picolyaminoformyl))phenoxyl]methyl}methane (L(II)). A series of zero- to three-dimensional lanthanide coordination complexes have been obtained by changing the substituents on the Pentaerythritol. Our results revealed that, complexes of the L(I) ligand, {Ln(4)L(I)(3)(NO(3))(12).nC(4)H(10)O}(infinity) (Ln = Nd, Eu, Tb, Er, n = 3 or 6)] show the binodal 3,4-connected three-dimensional interpenetration coordination polymers with topology of a (8(3))(4)(8(6))(3) notation. Compared to L(I), complexes of L(II) present a cage-like homodinuclear [Ln(2)L(II)(2)(NO(3))(6).2H(2)O].nH(2)O (Ln = Nd, Tb, Dy, n = 0 or 1) or a helical one-dimensional coordination {[ErL(II)(NO(3))(3).H(2)O].H(2)O}(infinity) polymer. The luminescence properties of the resulting complexes formed with ions used in fluoroimmunoassays (Ln = Eu, Tb) are also studied in detail. It is noteworthy that subtle variation of the terminal group from benzene to pyridine not only sensibly affects the overall molecular structures but also the luminescence properties as well.     

Synthesis and luminescence properties of lanthanide complexes with a new aryl amide bifunctional bridging ligand

A new aryl amide type bifunctional bridging ligand 4,4'-bis{[(2'-benzylaminoformyl)phenoxyl]methyl}-1,1'-biphenyl (L) and its complexes with lanthanide ions (Ln=Pr, Eu, Gd, Tb, Ho, Er) were synthesized and characterized by elemental analysis, infrared spectra, conductivity measurements and thermal analysis. At the same time, the luminescence properties of the Eu and Tb complexes in acetone solutions were investigated. Under the excitation of UV light, these two complexes exhibited characteristic emission of europium and terbium ions. And the lowest triplet state energy level T1 of this ligand matches better to the lowest resonance energy level of Tb(III) than to Eu(III) ion.     

Synthesis and infrared and fluorescent properties of rare earth complexes with a new aryl amide podand

Solid complexes of rare earth nitrates and picrates with a new aryl amide podand, 1,4-bis{[(2'-benzylamino-formyl)phenoxyl]methyl}-naphthaline (L) were synthesized. The complexes were characterized by elemental analysis, IR and molar conductivity measurements. At the same time, the fluorescent properties of the Eu(III) and Tb(III) nitrates and picrates complexes in solid state were also investigated. Under the excitation, these complexes exhibited characteristic emissions of europium and terbium ions. The counter anion factor influencing the fluorescent intensity was also discussed.     

Tuning the self-assembly and luminescence properties of lanthanide coordination polymers by ligand design

Two new structure-related tripodal ligands featuring salicylamide pendant arms, 1,3,5-tris{[(2'-furfurylaminoformyl)phenoxyl]methyl}-2,4,6-trimethylbenzene (L(I)) and 1,1,1-tris{[(2'-furfurylaminoformyl)phenoxyl]methyl}ethane (L(II)) have been designed and synthesized with the ultimate aim of self-assembling lanthanide polymers with interesting luminescent properties. Among two series of Ln(III) nitrate complexes (Ln = Pr, Nd, Sm, Eu, Gd, Tb or Dy) which have been characterized by elemental analyses, XRD, TGA and IR spectra, three new coordination polymers have been determined by X-ray diffraction analysis. The coordination polymer type {[Ln(NO(3))(3)(L(I))].nH(2)O}(n) possesses an unusual ladderlike double chain which can be further connected through pi-pi stacking interactions constructing a three-dimensional supramolecular structure. In contrast, the coordination polymer type {[Ln(NO(3))(3)(L(II))].nCH(3)OH}(n) displays a (3,3)-connected puckered two-dimensional net with 4.8(2) topological notation. The photophysical properties of the Sm, Eu, Tb and Dy complexes at room temperature are investigated. The present work substantiates the claim that the supramolecular structure as well as the luminescent properties of the coordination polymer can be tuned by varying either the backbone group or the terminal group of the organic ligand.     

Synthesis and infrared and luminescence spectra of rare earth complexes with a new hexapodal ligand

Solid complexes of rare earth nitrates and picrates with a new hexapodal ligand, 1,2,3,4,5,6-hexa{[(2'-benzylamino-formyl)phenoxyl]methyl}-benzene (L) have been prepared. These complexes were characterized by elemental analysis, IR and molar conductivity. At the same time, the luminescence properties of the Eu(III) and Tb(III) nitrates and picrates complexes in solid state were also investigated. Under the excitation of UV light, these complexes exhibited characteristic emission of europium and terbium ions. The influence of the counter anion on the luminescent intensity was also discussed.     

Low-valent vanadium complexes of a pyrrolide-based ligand. Electronic structure of a dimeric V(I) complex with a short and weak metal-metal bond

Deprotonation of the nitrogen atoms of the two pyrrole rings of 1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene with KH followed by further reaction with either VCl 3(THF) 3 or with VCl 2(TMEDA) 2 respectively gave the paramagnetic complexes [1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene]VCl(DME) ( 1) and [1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene]V(THF) 3 ( 2). Further reduction with the appropriate amount of KH afforded diamagnetic dinuclear [1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene]V} 2] ( 3). In complex 3, the bridging interaction between the two metal centers is realized via the ligand central benzene ring. Density functional theory calculations have elucidated the nature of the electronic interaction between the two metals with the bridging pi-system thus accounting for its visible structural distortion. Calculations also pointed out the presence of only a weak V-V bond in spite of the short V-V distance.     

Synthesis of Ethyl 2,2-Bis{[(benzoylcarbamothioyl)oxy]methyl}propanoate and Its Complexes with Copper(II) and Cobalt(II) Ions

Russian Journal of General Chemistry - The structures of ethyl 2,2-bis{[(benzoylcarbamothioyl)oxy]methyl}propanoate and its 1 : 1 complexes with copper(II) and cobalt(II) ions were determined by...     

Formation and characterization of Co(III)-semiquinonate phenoxyl radical species

Co(III) complexes of N(3)O-donor tripodal ligands, 2,4-di(tert-butyl)-6-{[bis(2-pyridyl)methyl]aminomethyl}phenolate (tbuL), 2,4-di(tert-butyl)-6-{[bis(6-methyl-2-pyridyl)methyl]aminomethyl}phenolate (tbuL(Mepy)(2)), were prepared, and precursor Co(II) complexes, [Co(tbuL)Cl] (1) and [Co(tbuL(Mepy)(2))Cl] (2), and ternary Co(III) complexes, [Co(tbuL)(acac)]ClO(4) (3), [Co(tbuL)(tbu-cat)] (4), and [Co(tbuL(Mepy)(2))(tbu-SQ)]ClO(4) (5), where acac, tbu-cat, and tbu-SQ refer to pentane-2,4-dionate, 3,5-di(tert-butyl)catecholate, and 3,5-di(tert-butyl)semiquinonate, respectively, were structurally characterized by the X-ray diffraction method. Complexes 3 and 5 have a mononuclear structure with a fac-N(3)O(3) donor set, while 4 has a mer-N(3)O(3) structure. The cyclic voltammogram (CV) of complex 3 exhibited one reversible redox wave centered at 0.93 V (vs Ag/AgCl) in CH(3)CN. Complex 5 was converted to a phenoxyl radical species upon oxidation with Ce(IV), showing a characteristic pi-pi* transition band at 412 nm. The ESR spectrum at low temperature and the resonance Raman spectrum of 3 established that the radical species has a Co(III)-phenoxyl radical bond. On the other hand, the CVs showed two oxidation processes at E(1/2) = 0.01 and E(pa) = 0.92 V for 4 and E(1/2a) = 0.05 and E(1/2b) = 0.69 V for 5. The rest potential of 4 (-0.11 V) was lower than the E(1/2) value, whereas that of 5 (0.18 V) was higher, indicating that the first redox wave of 4 and 5 is assigned to the tbu-cat and the tbu-SQ redox process, respectively. One-electron oxidized 4 showed absorption, resonance Raman, and ESR spectra which are similar to those of 5, suggesting formation of a stable Co(III)-semiquinonate species, which has the same oxidation level of 5. The resonance Raman spectrum of two-electron oxidized 4 showed the nu(8a) bands of the semiquinonate and phenoxyl radical, which were absent in the spectrum of one-electron oxidized 5. Since both oxidized species were ESR inactive at 5 K, the former was concluded to be a biradical species containing semiquinonate and phenoxyl radicals coupled antiferromagnetically and the latter to a species with a coordinated quinone.     

Solvent- and temperature-controlled in situ ligand reactions mediated by Cu(II) and 3'-[(E)-{[(1S,2S)-2-aminocyclohexyl]imino}methyl]-4'-hydroxy-4-biphenylcarboxlic acid

Three new compounds, CuL, CuL', and Cu(2)O(2)L'(2) (H(2)L = 3'-[(E)-{[(1S,2S)-2-aminocyclohexyl]imino}methyl]-4'-hydroxy-4-biphenylcarboxlic acid, H(2)L' = 3'-[(E)-{[(1S,2S)-2-aminocyclohexyl]imino}methyl]-4'-hydroxy-5'-nitro-4-biphenylcarboxlic acid, H(2)L' = 3'-(N,N-dimethylamino methyl)-4'-hydroxy-4-biphenylcarboxlic acid), were selectively synthesized through a controlled in situ ligand reaction system mediated by copper(II) nitrate and H(2)L. Selective nitration was achieved by using different solvent mixtures under relatively mild conditions, and an interesting and economical reductive amination system in DMF/EtOH/H(2) O was also found. All crystal structures were determined by single-crystal X-ray diffraction analysis. Both CuL and CuL' display chiral 1D chain structures, whereas Cu(2)O(2)L'(2) possesses a structure with 13×16?? channels and a free volume of 41.4?%. The possible mechanisms involved in this in situ ligand-controlled reaction system are discussed in detail.     

Preparation, characterization and luminescent properties of lanthanide complexes with a new aryl amide bridging ligand

A new aryl amide type bridging ligand 1,4-bis{[(2'-benzylaminoformyl)phenoxyl]ethoxyl}benzene (L) and its complexes with lanthanide ions (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) were synthesized and characterized by elemental analysis, infrared spectra and electronic spectra. At the same time, the luminescent properties of the Sm, Eu, Tb and Dy complexes in solid state and the Tb complex in solvents were also investigated. At room temperature, these four complexes exhibited characteristic luminescence emissions of the central metal ions under UV light excitation and could be significant in the field of supramolecular photonic devices.     

Ancillary ligand functionalization of cyanide-bridged S = 6 Fe(III)4Ni(II)4 complexes for molecule-based electronics

Treatment of 1-chloro-6-iodohexane or 1-chloro-10-iododecane with lithium tris(pyrazolyl)methanide, followed by potassium thioacetate, affords bifunctional 1-S(acetyl)-tris(pyrazolyl)alkanes (L) (pz)3C(CH2)nSAc (n = 6, 1; 10, 2). Magnetic studies of {[(pzTp)Fe(III)(CN)3]4[Ni(II)L]4[OTf]4}.solvent (4, L = 1; 5, L = 2) boxes suggest that -(CH2)6 chains (4) limit intermolecular interactions while -(CH2)10 chains in 5 introduce crystallographic disorder and a distribution of relaxation times; 4 and 5 exhibit slow relaxation of the magnetization.     

Assembly, crystal structure, and luminescent properties of three-dimensional (10,3)-a netted rare earth coordination polymers

Solid complexes [REL(NO3)3]n with novel (10,3)-a type three-dimensional networks structure have been assembled using rare earth nitrates and an amide type semirigid tripodal bridging ligand, 1,3,5-tris {[(2′-benzylaminoformyl)phenoxyl]methyl}benzene (L), as building blocks. The complexes were crys- tallized in the orthorhombic system with chiral space group P212121. The whole structure consists of an infinite array of trigonal RE(III) ions bridged by tridentate ligands, and a novel (10,3)-a net is formed, which is very uncommon in the rare earth complexes. At room temperature, the Sm(III), Eu(III), Tb(III), Dy(III) complexes all exhibited characteristic luminescence emissions of central metal ions under UV light excitation.     

Luminescence tuning of imidazole-based lanthanide(III) complexes [Ln = Sm, Eu, Gd, Tb, Dy

To tune the lanthanide luminescence in related molecular structures, we synthesized and characterized a series of lanthanide complexes with imidazole-based ligands: two tripodal ligands, tris{[2-{(1-methylimidazol-2-yl)methylidene}amino]ethyl}amine (Me(3)L), and tris{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(3)L), and the dipodal ligand bis{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(2)L). The general formulas are [Ln(Me(3)L)(H(2)O)(2)](NO(3))(3)·3H(2)O (Ln = 3+ lanthanide ion: Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)), [Ln(H(3)L)(NO(3))](NO(3))(2)·MeOH (Ln(3+) = Sm (6), Eu (7), Gd (8), Tb (9), and Dy (10)), and [Ln(H(2)L)(NO(3))(2)(MeOH)](NO(3))·MeOH (Ln(3+) = Sm (11), Eu (12), Gd (13), Tb (14), and Dy (15)). Each lanthanide ion is 9-coordinate in the complexes with the Me(3)L and H(3)L ligands and 10-coordinate in the complexes with the H(2)L ligand, in which counter anion and solvent molecules are also coordinated. The complexes show a screw arrangement of ligands around the lanthanide ions, and their enantiomorphs form racemate crystals. Luminescence studies have been carried out on the solid and solution-state samples. The triplet energy levels of Me(3)L, H(3)L, and H(2)L are 21?000, 22?700, and 23?000 cm(-1), respectively, which were determined from the phosphorescence spectra of their Gd(3+) complexes. The Me(3)L ligand is an effective sensitizer for Sm(3+) and Eu(3+) ions. Efficient luminescence of Sm(3+), Eu(3+), Tb(3+), and Dy(3+) ions was observed in complexes with the H(3)L and H(2)L ligands. Ligand modification by changing imidazole groups alters their triplet energy, and results in different sensitizing ability towards lanthanide ions.     

Nitroimidazole and glucosamine conjugated heteroscorpionate ligands and related copper(II) complexes. Syntheses, biological activity and XAS studies

New nitroimidazole and glucosamine conjugated heteroscorpionate ligands, namely 2,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide (L(MN)) and 1,3,4,6-tetra-O-acetyl-2-{[bis(3,5-dimethyl-1H-pyrazol-1-yl)acetyl]amino}-2-deoxy-β-D-glucopyranose (L(DAC)), respectively, were synthesized by direct coupling of preformed side chain acid and amine components. The related copper(II) complexes {[(L(MN))(2)Cu]Cl(2)}, and {[(L(DAC))(2)Cu]Cl(2)} have been prepared from the reaction of CuCl(2)*2H(2)O with L(MN) or L(DAC) ligand in methanol solution. Single crystal structural characterization was undertaken for the L(MN) ligand. In the absence of a coordinated metal core, the overall arrangement of the ligand is determined by some loose intra- and inter-molecular nonbonding contacts. X-Ray Absorption Spectroscopy (XAS) has been used to probe the local structure of the two copper(II) complexes, {[(L(MN))(2)Cu]Cl(2)} and {[(L(DAC))(2)Cu]Cl(2)}. The EXAFS analysis has permitted the identification of the local environment of the copper site. Copper interacts with 2 units of ligand in both complexes, and it is found to be 6-fold coordinated. Its local structure is described by four Cu-N and two Cu-O interactions to form a pseudo-octahedron core, with a 0.14 ? lengthening of the Cu-O bond length in the case of L(DAC) complex with respect to the L(MN) one, likely due to the higher steric hindrance of the glucosamine moiety. The XANES analysis agrees with these results, also confirming the Cu(II) formal copper oxidation state for both complexes. The new copper(II) complexes {[(L(MN))(2)Cu]Cl(2)} and {[(L(DAC))(2)Cu]Cl(2)} as well as the corresponding uncoordinated ligands were evaluated for their cytotoxic activity towards a panel of several human tumour cell lines. The results reported here indicate that both copper(II) complexes show similar spectra of cytotoxicity and very low resistance factors (RF < 2) against C13* ovarian cancer cells which have acquired resistance to cisplatin.     

Synthesis, characterization, and the antioxidative activity of 4-{[(3,4-dimethyl pyrrole-2-carbonyl)hydrazono](phenyl)methyl}-3-methyl-1-phenylpyrazol-5-ol and Its zinc(II), copper(II), nickel(II) complexes

A new ligand H(3)L, 4-{[(3,4-dimethylpyrrole-2-carbonyl)hydrazono](phenyl)methyl}-3-methyl-1-phenylpyrazol-5-ol and its three transition metal complexes, M(H(2)L)OAc.H(2)O (M=Cu, Ni), Zn(H(2)L)(2) have been synthesized and fully characterized on the basis of ESI-MS, elemental analyses, molar conductivities, IR spectra and (1)H-NMR. In addition, their antioxidative activities have been investigated by spectrophotometer measurements. The experimental results show that the complexes have higher activity in the suppression of O(2)(*-) and *OH than the free ligand.     

Potentiometric Membrane Electrode for Cr(III) Ion Based on a New Aryl Amide Bifunctional Bridging Ligand as a Neutral Carrier

A novel Cr(III) ion‐selective electrode is constructed by incorporating a new aryl amide bifunctional bridging ligand, 2,2′‐bis{[(2″‐benzylaminoformyl)phenxoyl]methyl}‐diethylether (BBPMD) as a neutral carrier into the PVC matrix. The proposed electrode, with optimum membrane composition, exhibits an excellent near‐Nernstian response for Cr³⁺ ion ranging from 2.8 × 10^?6 to 1.0 × 10^?1 mol/L with a detection limit of 8.6 × 10^?7 mol/L and a slope of 19.5 ± 0.2 mV/dec in pH 3.0 nitrate buffer solution at 25 °C. It has an appropriate response time, suitable reproducibility, and good selectivity towards Cr³⁺ ion. The operational pH range of the proposed electrode is 2.5–6.5. The response mechanism was discussed in view of UV‐vis spectroscopy and the A. C. impedance technique. The excellent analytical features of the proposed electrode could lead to its successful application as an indicator electrode in potentiometric titration of Cr³⁺ ion and in the direct determination of Cr³⁺ ion in tea leaves and coffee samples.     

Synthesis, characterization, and OFET properties of amphiphilic heteroleptic tris(phthalocyaninato) europium(III) complexes with hydrophilic poly(oxyethylene) substituents

A series of amphiphilic heteroleptic tris(phthalocyaninato) europium complexes with hydrophilic poly(oxyethylene) heads and hydrophobic alkoxy tails {Pc[(OC2H4)2OCH3]8}Eu{Pc[(OC2H4)2OCH3]8}Eu[Pc(OCnH2n + 1)8] (n = 6, 8, 10,12) (1-4) were designed and prepared from the reaction between homoleptic bis(phthalocyaninato) europium compound {Pc[(OC2H4)2OCH3]8}Eu{Pc[(OC2H4)2OCH3]8} and metal-free 2,3,9,10,16,17,23,24-octakis(alkoxy)phthalocyanine H2Pc(OCnH2n + 1)8 (n = 6, 8, 10,12) in the presence of Eu(acac)3.H2O (Hacac = acetylacetone) in boiling 1,2,4-trichlorobenzene (TCB). These novel sandwich triple-decker complexes have been characterized by a wide range of spectroscopic methods and have been electrochemically studied. With the help of the Langmuir-Blodgett (LB) technique, these typical amphiphilic triple-decker complexes have been fabricated into organic field effect transistors (OFET) with an unusual bottom contact configuration. The devices display good OFET performance with the carrier mobility for holes in the direction parallel to the aromatic phthalocyanine rings, which shows dependence on the length of the hydrophobic alkoxy side chains, decreasing from 0.46 for 1 to 0.014 cm2 V(-1) s(-1) for 4 along with the increase in the carbon number in the hydrophobic alkoxy side chains.     

Condensation of Propan-2-one with Formaldehyde and Propane-2-thiol

Three-component condensation of propan-2-one with formaldehyde and propane-2-thiol in the presence of sodium hydroxide afforded 3-{[(propan-2-yl)sulfanyl)]methyl}but-3-en-2-one or 4-[(propan-2-yl)sulfanyl]-3-{[(propan-2-yl)sulfanyl]methyl}butan-2-one, depending on the amount of the base. The formation of 4-[(propan-2-yl)sulfanyl]-3-{[(propan-2-yl)sulfanyl]methyl}butan-2-one from 4-[(propan-2-yl)sulfanyl]butan-2-one involved aldol condensation of the latter with formaldehyde and subsequent nucleophilic addition of propane-2-thiol to the C=C double bond of intermediate 3-{[(propan-2-yl)sulfanyl]methyl}but-3-en-2-one in the presence of sodium hydroxide.     

Solvent‐ and catalyst‐free reaction of (aminomethyl)phosphonates with epoxides: Synthesis of novel {[(2‐hydroxyethyl)amino]methyl}phosphonates

Uncatalyzed reaction of epoxides with (aminomethyl)phosphonates for the synthesis of novel {[(2‐hydroxyethyl)amino]methyl}phosphonates is described. Treatment of (aminomethyl)phosphonates with epoxides without any catalyst and under solvent‐free conditions gives novel {[(2‐hydroxyethyl)amino]methyl}phosphonates. Using this method, a series of {[(2‐hydroxyethyl)amino]methyl}phosphonates was synthesized in good yields. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:284–289, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20615