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1.
The imidazolium salts 1,1′-dibenzyl-3,3′-propylenediimidazolium dichloride and 1,1′-bis(1-naphthalenemethyl)-3,3′-propylenediimidazolium dichloride have been synthesized and transformed into the corresponding bis(NHC) ligands 1,1′-dibenzyl-3,3′-propylenediimidazol-2-ylidene (L1) and 1,1′-bis(1-naphthalenemethyl)-3,3′-propylenediimidazol-2-ylidene (L2) that have been employed to stabilize the PdII complexes PdCl22-C,C-L1) (2a) and PdCl22-C,C-L2) (2b). Both latter complexes together with their known homologous counterparts PdCl22-C,C-L3) (1a) (L3 = 1,1′-dibenzyl-3,3′-ethylenediimidazol-2-ylidene) and PdCl22-C,C-L4) (1b) (L4 = 1,1′-bis(1-naphthalenemethyl)-3,3′-ethylenediimidazol-2-ylidene) have been straightforwardly converted into the corresponding palladium acetate compounds Pd(κ1-O-OAc)22-C,C-L3) (3a) (OAc = acetate), Pd(κ1-O-OAc)22-C,C-L4) (3b), Pd(κ1-O-OAc)22-C,C-L1) (4a), and Pd(κ1-O-OAc)22-C,C-L2) (4b). In addition, the phosphanyl-NHC-modified palladium acetate complex Pd(κ1-O-OAc)22-P,C-L5) (6) (L5 = 1-((2-diphenylphosphanyl)methylphenyl)-3-methyl-imidazol-2-ylidene) has been synthesized from corresponding palladium iodide complex PdI22-P,C-L5) (5). The reaction of the former complex with p-toluenesulfonic acid (p-TsOH) gave the corresponding bis-tosylate complex Pd(OTs)22-P,C-L5) (7). All new complexes have been characterized by multinuclear NMR spectroscopy and elemental analyses. In addition the solid-state structures of 1b·DMF, 2b·2DMF, 3a, 3b·DMF, 4a, 4b, and 6·CHCl3·2H2O have been determined by single crystal X-ray structure analyses. The palladium acetate complexes 3a/b, 4a/b, and 6 have been employed to catalyze the oxidative homocoupling reaction of terminal alkynes in acetonitrile chemoselectively yielding the corresponding 1,4-di-substituted 1,3-diyne in the presence of p-benzoquinone (BQ). The highest catalytic activity in the presence of BQ has been obtained with 6, while within the series of palladium-bis(NHC) complexes, 4b, featured with a n-propylene-bridge and the bulky N-1-naphthalenemethyl substituents, revealed as the most active compound. Hence, this latter precursor has been employed for analogous coupling reaction carried out in the presence of air pressure instead of BQ, yielding lower substrate conversion when compared to reaction performed in the presence of BQ. The important role of the ancillary ligand acetate in the course of the catalytic coupling reaction has been proved by variable-temperature NMR studies carried out with 6 and 7′ under catalytic reaction conditions.  相似文献   

2.
A series of 2-(1-aryliminoethylidene)quinolines (L) were synthesized and used as bidentate N^N ligands in coordinating with metal (cobalt and iron) chlorides to form complexes of the type LMCl2, cobalt(II) (Co1-Co5) and iron(II) (Fe1-Fe5). All organic compounds and metal complexes were fully characterized, and the molecular structures of the representative complexes Co3·DMF and Fe4·DMF were confirmed as distorted bipyramidal geometry at the metal by single-crystal X-ray diffraction. Upon activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO) under 10 atm ethylene, all complexes showed high activities in ethylene dimerization with activities of up to 1.82 × 106 g mol−1 (Co) h−1 and 5.89 × 105 g mol−1 (Fe) h−1, respectively.  相似文献   

3.
Two novel amino acids imine ligands (H2L1 and H2L2) have been synthesized using green condensation reaction from 2‐[3‐Amino‐5‐(2‐hydroxy‐phenyl)‐5‐methyl‐1,5‐dihydro‐[1, 2, 4]triazol‐4‐yl]‐3‐(1H‐indol‐3‐yl)‐propionic acid with benzaldehyde/p‐flouro benzaldehyde (1:1 molar ratio) in the presence of lemon juice as a natural acidic catalyst in aqueous medium. Their transition metal complexes have been prepared in a molar ratio (1:1). Characterization of the ligands and complexes using elemental analysis, spectroscopic studies, 1HNMR, 13CNMR, and thermal analysis has been reported. E*, ΔH*, ΔS* and ΔG* thermodynamic parameters, were calculated to throw more light on the nature of changes accompanying the thermal decomposition process of these complexes. The molar conductance measurement of metal complexes showed nonelectrolyte behavior. The metal complexes of the two ligands have tetrahedral geometry with a general molecular structure [M(H2L)Xn], where [(M = Mn (II), Co (II), Cu (II) and Zn (II), X = Cl, n = 2]; M = VO (II), X = SO4, n = 1] for H2L1. [M = Co (II), Cu (II), Zn (II)] for H2L2. Antibacterial activity of the complexes against (Bacillis subtilis, Micrococcus luteus, Escherichia coli), also antifungal activity against (Aspergillus niger, Candida Glabarta, Saccharomyces cerevisiae) have been screened. The results showed that all complexes have antimicrobial activity higher than free ligands. Molecular docking studies results showed that, all the synthesized compounds having minimum binding energy and have good affinity toward the active pocket, thus, they may be considered as good inhibitor of targeting PDB code: 1SC7 (Human DNA Topo‐isomerase I).  相似文献   

4.
Two novel tripodal imine-phenol ligands, cis,cis-1,3,5-tris{(2-hydroxybenzilidene)aminomethyl}cyclohexane (TMACHSAL, L1) and of cis,cis-1,3,5-tris{[(2-hydroxyphenyl)ethylidene]aminomethyl}cyclohexane (Me3-TMACHSAL, L2) have been synthesized and characterized by elemental analyses and various spectral (UV–vis, IR and 1H and 13C NMR) data. The complexation reactions of the ligands with H+ and Fe(III) were investigated by potentiometric and spectrophotometric methods at an ionic strength of 0.1 M KCl and 25 ± 1 °C in aqueous medium. Three protonation constants each for ligands L1 and L2 were determined and were used as input data to evaluate the formation constants of the metal complexes. Formations of metal complexes of the types FeLH3, FeLH2, FeLH, FeL and FeLH−1 were depicted in solution. Experimental evidences suggested for a formation of tris(iminophenolate) type metal complex by the ligands. The ligand L1 showed higher affinity towards iron(III) than L2. The pFe value related to L1 (pFe = 20.14) is approximately four units higher than L2 (pFe = 16.41) at pH = 7.4. The structures of the metal complexes were proposed through the molecular mechanics calculation using MM3 force field followed by semi-empirical PM3 method.  相似文献   

5.
The Ni(II) and Cu(II) complexes of four azo compounds (H2L1–4), namely, 2-(p-X-phenylazo)-4-acetamidophenol (X = OCH3, NO2, Br, and H for H2L1, H2L2, H2L3, and H2L4, respectively) were prepared and characterized on the basis of their analytical, spectroscopic, magnetic, and conductance data. The isolated complexes are found to have the general formulae [M(HL1–4)Cl(H2O)3] (M = Ni(II) and Cu(II)). The chelates are found to have octahedral structure. The infrared spectra show that H2L1–4 ligands are coordinated to the metal ions in a uninegative bidentate manner, with NO donor sites of the azo N and the deprotonated phenolic O. The ligands and their chelates are subjected to thermal analysis. The biological activity of the synthesized ligands and their metal complexes also are screened against the adult Tribolium confusum mortality. They showed remarkable biological activity.  相似文献   

6.
The reaction of binucleating thioamide ligands (L1-L3) with [PdCl2(PPh3)2] in 1:2 molar ratio in methanol medium afforded a series of binuclear palladium(II) complexes. The synthesized complexes were characterized by elemental analysis and 1H NMR. The molecular structure of one of the complexes was established by X-ray diffraction method. The binuclear palladium(II) thioamide complex has been shown to be an active catalyst for the Heck reaction of aryl bromides with alkenes.  相似文献   

7.
The aqueous coordination behavior of two novel tripodal imine-phenol ligands, cis,cis-1,3,5-tris{(2-hydroxybenzilidene)aminomethyl}cyclohexane (TMACHSAL, L1) and cis,cis-1,3,5-tris{[(2-hydroxyphenyl)ethylidene]aminomethyl}cyclohexane (Me3- TMACHSAL, L2) with Al3+ and Ga3+ has been investigated at an ionic strength of 0.1 mol⋅dm−3 KCl and 25±1 °C by potentiometric and spectrophotometric methods. Both ligands formed various monomeric metal complex species MLH3, MLH2, MLH, ML and MLH−1 with Ga(III); and MLH3, ML and MLH−1 with Al(III). The Ga(III) complexes showed higher thermodynamic stability than the Al(III) complexes. Semi-empirical PM6 calculations along with TDDFT/B3LYP/3-21G calculations have been performed to complement the experimental measurements. The calculated structure of the metal complexes predicted a distorted octahedral geometry where favorable ring-flipping from the equatorial conformation in uncomplexed ligands to the axial conformation was observed upon chelation.  相似文献   

8.
A series of ruthenium (II) complexes, [Ru(bpy)2L]X2 (L = L1, L2; X = Cl, PF6, SCN), were synthesized based on bipyridine and two novel diimine ligands L1 and L2 (L1 = 1-(4-5′-phenyl-1,3,4-oxadiazolylphenyl)-2-pyridinyl-benzoimidazole, L2 = 1-(4-carbazolylphenyl)-2-pyridinylbenzimidazole); and the crystal structure of [Ru(bpy)2L1]Cl2 was also described. [Ru(bpy)2(Pybm)]X2 (Pybm = 2-(2-pyridine)benzimidazole) complexes were also prepared as reference samples. In the UV-vis absorption spectra there are one strong π → π* transition and two dπ (Ru) → π* transitions. By comparisons of photoluminescence properties between [Ru(bpy)2L]X (L = L1, L2) and the reference complexes we find that the complexes with carrier-transporting groups of carbazole and oxadizole have the higher emission intensity and quantum efficiency. One reversible oxidation process in the range 0.80-1.00 V exists in each of the complexes which is assigned to the metal oxidation, [Ru(III)(bpy)2L]2+ + e?[Ru(II)(bpy)2L]+.  相似文献   

9.
Three new coordination complexes, 2{[Co(L1)2]ClO4} · 0.5CH3OH (1), [Mn(L2)2] (2), and [Cu(HL2)(L2)]ClO4 · 2H2O (3) have been synthesized from two tridentate N,N,O-donor hydrazone ligands HL1, 2-acetylpyridine-salicyloylhydrazone, and HL2, 2-benzoylpyridine-salicyloylhydrazone, respectively and thoroughly characterized by elemental analysis, FT-IR, UV–Vis, electrochemical, and room temperature magnetic susceptibility measurements. Structures of the complexes have been unequivocally established by single crystal X-ray diffraction technique. Structural analysis reveals that 1 consists of two chemically similar but crystallographically independent cationic [Co(L1)2]+ units and 2 consists of a neutral [Mn(L2)2] molecule while 3 consists of a cationic [Cu(HL2)(L2)]+ unit. Metal ions display distorted octahedral geometry in 1 and 2 while in 3 it shows a distorted square pyramidal geometry. Ligand conformations around the metal ions are stabilized by the presence of intra-ligand hydrogen bonding in all the complexes. Structure of 3 reveals that a perchlorate ion linked to the complex by hydrogen bonding via a water molecule.  相似文献   

10.
A series of palladium complexes of general formula [(Acac)PdL1L2]+A, where L1, L2 = phosphines and A = BF4, CF3SO3, were synthesized. Preliminary studies show that the complexes are active in selective dimerization of styrene and addition polymerization of norbornene.  相似文献   

11.
The complexes (μ3-L1/L2)[Ru(acac)2]3, acac = 2,4-pentanedionato, L1 = 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2′,3′-c]phenazine and L2 = 2,3,8,9,14,15- hexamethyldiquinoxalino[2,3-a:2′,3′-c]phenazine, undergo stepwise one-electron oxidation involving a total of three electrons and stepwise one-electron reduction with three (L2) or four electrons (L1). All reversibly accessible states were characterized by UV–Vis–NIR spectroelectrochemistry. Oxidation leads to mixed-valent intermediates {(μ3-L)[Ru(acac)2]3}+ and {(μ3-L)[Ru(acac)2]3}2+ of which the RuIIIRuIIRuII combinations exhibit higher comproportionation constants Kc than the RuIIIRuIIIRuII states – in contrast to a previous report for the unsubstituted parent systems {(μ3-L3)[Ru(acac)2]3}+/2+, L3 = diquinoxalino[2,3-a:2′,3′-c]phenazine. No conspicuous inter-valence charge transfer absorptions were observed for the mixed-valent intermediates in the visible to near-infrared regions. The monocations and monoanions were characterized by EPR spectroscopy, revealing rhombic ruthenium(III) type signals for the former. Electron addition produces ruthenium(II) complexes of the reduced forms of the ligands L, a high resolution EPR spectrum with 14N and 35,37Cl hyperfine coupling and negligible g anisotropy was found for {(μ3-L1)[Ru(acac)2]3}. DFT calculations of (μ3-L1)[Ru(acac)2]3 confirm several ligand-centered low-lying unoccupied MOs for reduction and several metal-based high-lying occupied MOs for electron withdrawal, resulting in low-energy metal-to-ligand charge transfer (MLCT) transitions.  相似文献   

12.
The dimanganese hydride complexes [Mn2(μ-H)2(CO)6(μ-L2)] [L2 = (EtO)2POP(OEt)2 (tedip), Ph2PCH2PPh2 (dppm)] react with primary and secondary silanes H2SiPhR (R = Ph, Me, H) to give the corresponding derivatives [Mn2(μ-H2SiPhR)(CO)6(μ-L2)] having a silane molecule displaying a relatively unusual μ-κ22 coordination mode (averaged values are ca. Mn-H = 1.59 Å, H-Si = 1.69 Å and Mn-Si = 2.381 Å, when R = Ph and L2 = tedip). These complexes display in solution cis and/or trans arrangement of the bridging silane relative to the diphosphorus ligands (and facial and/or meridional arrangements of the corresponding carbonyl ligands), depending on the bridging groups. The novel unsaturated dihydride [Mn2(μ-H)2(CO)6(μ-dmpm)] (dmpm = Me2PCH2PMe2) has been prepared through the reaction of [Mn2(μ-Cl)2(μ-dmpm)(CO)6] and 5 equiv of Li[BH2Me2] in tetrahydrofuran followed by addition of water. The dihydride complexes [Mn2(μ-H)2(CO)6(μ-L2)] (L2 = tedip, dppm, dmpm) react with HSnPh3 to give different mixtures of products strongly dependent on the particular reaction conditions. We have thus been able to isolate and characterize five new types of dimanganese-tin derivatives: [Mn2(μ-SnPh2)2(CO)6(μ-L2)], [Mn2(μ-H)(μ-Ph2SnO(H)SnPh2)(CO)6(μ-L2)] (average values are Mn-Sn = 2.54 Å, Sn-O = 2.11 Å, when L2 = tedip), [Mn2(μ-H)(μ-κ12-HSnPh2)(CO)6(μ-L2)], [Mn2(μ-H)(μ-κ11-O(H)SnPh2)(CO)6(μ-L2)], and [Mn2(μ-H)(SnPh3)(CO)7(μ-L2)] (Mn-Mn = 3.237(1) Å, Mn-Sn = 2.642(1) Å, when L2 = dppm).  相似文献   

13.
The reaction of a series of tripodal ligands, H3L1,2 and L3-6, with [M(PPh3)2Cl2] (M = Ru, Os) affords a family of coordination cage compounds of the type [MIIIL1,2] (1-4) or [MIIL3-6](BPh4)2 (5-12). The Schiff base ligands (H3L1, L3, L5) have been synthesized by condensation of tris(2-aminoethyl)amine with salicylaldehyde, pyridine-2-aldehyde and 1-methyl-2-imidazolecarboxaldehyde. These ligands were further reduced and subsequently methylated to form the new ligands (H3L2, L4, L6). Single crystal X-ray diffraction studies of 1 and 2 show that the tripodal ligand wraps around the metal center as a hexadentate ligand to form a cage. All the synthesized compounds have been thoroughly characterized by ESI-MS, FT-IR, UV-Vis and NMR spectroscopic methods. To the best of our knowledge, this is the first ever report of osmium complexes with tris(2-aminoethyl)amine based tripodal ligands. DFT calculations were performed to obtain geometry optimized structures of all the other complexes (3-12).  相似文献   

14.
The reaction of [Pd(CH3CN)2Cl2] with N ‐functional group‐substituted 2‐iminomethylpyrrole‐based ligands, namely N 1‐((1H‐pyrrol‐2‐yl)methylene)‐N 3,N 3‐dimethylpropane‐1,3‐diamine (LA), N 1‐((1H‐pyrrol‐2‐yl)methylene)‐N 3‐methyl‐N 3‐phenylpropane‐1,3‐diamine (LB), N ‐((1H‐pyrrol‐2‐yl)methylene)‐3‐(methylthio)propan‐1‐amine (LC) and N ‐((1H‐pyrrol‐2‐yl)methylene)‐3‐methoxypropan‐1‐amine (LD), resulted in [Ln PdCl] (Ln  = LA–LD) complexes in high yield via N─H bond activation of pyrrole moiety without use of base. [Ln PdCl] existed as monomeric four‐coordinated complexes with slightly distorted square planar geometries around the palladium metal center. The ligands show N ,N ′,X ‐tridentate binding mode to the palladium metal center to give two fused ring metallacycles. [LBPdCl] gave the highest activity (3.29 × 105 g PMMA (mol Pd)−1 h−1) for a methyl methacrylate (MMA) polymerization in the presence of modified methylaluminoxane at 60 °C compared to the other Pd(II) analogues, and resulted in PMMA with higher molecular weight (M w = 7.16 × 105 g mol−1) and narrower polydispersity index. Syndiotactic‐enriched PMMA resulted in all cases.  相似文献   

15.
A series of mononuclear indenyl and pentamethylcyclopentadienyl ruthenium(II) complexes of formulation [(η5-L3)Ru(PPh3)(L2)]X, (where L3 = indenyl, pentamethylcyclopentadienyl; X = PF6 or BF4 and L2 = azine ligands) have been prepared by the reaction of [(η5-L3)Ru(PPh3)2(CH3CN)]X with the appropriate azine ligands in methanol or dichloromethane/benzene mixture. The reaction of nitro substituted azine ligands with the complexes [(η5-L3)Ru(PPh3)2(CH3CN)]X are solvent dependent. All these complexes were isolated as their PF6 or BF4 salts. The complexes were fully characterized with the help of microanalyses, FT-IR and NMR spectroscopy. The molecular structure of representative complexes 5c and 6a were established by single X-ray crystallography.  相似文献   

16.
The synthesis and antimicrobial activity of palladium(II) and platinum(II) complexes derived from heterocyclic bidentate ligands, namely 2‐(2′‐aminophenyl)benzoxazole [L1H2], 2‐(2′‐hydroxyphenyl)benzoxazole [L2H], and 2‐(2′‐mercaptophenyl)benzoxazole [L3H], are reported here. These complexes have been characterized by elemental analyses, molecular weight determinations, conductance measurements, infrared, 1H NMR, and electronic spectral studies. The resulting colored complexes are monomeric in nature. On the basis of above‐described studies, square‐planar geometry has been suggested for the resulting complexes. The ligands and their metal complexes were tested against certain microorganisms to assess their antimicrobial properties. The results indicate that the metal complexes are found more active than the parent ligands. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:44–50, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20578  相似文献   

17.
Three heterotopic ligands L1, L2, and L3 based on 1,10-phenanthroline and 2,2′-bipyridine moieties have been synthesized and characterized. The Ru(II) complexes [{Ru(bpy)2}33-L1)](PF6)6, [{Ru(bpy)2}33-L2)](PF6)6, and [{Ru(bpy)2}22-L3)](PF6)4 (bpy = 2,2′-bipyridine) have been prepared by refluxing Ru(bpy)2Cl2·2H2O with each ligand in ethanol. All three complexes display MLCT absorptions at around 455 nm and emissions at around 618 nm. Electrochemical studies of the complexes reveal one Ru(II)-centered quasi-reversible oxidation at around 1.32 V and three ligand-centered reductions in each case.  相似文献   

18.
A small difference in diamine bis(phenolato) ligands, namely an additional single methylene unit, directs formation of dinuclear Ti(IV) complexes rather than mononuclear ones as characterized by X-ray crystallography. Varying steric bulk of the ligand affects the coordination number in the dinuclear complexes and the ligand to metal ratio. A ligand with reduced steric bulk leads to a L2Ti2(OiPr)4 type complex featuring two octahedral metal centers bridged only by the two phenolato ligands, whereas a bulky ligand leads to a Ti2(μ-L1)(μ-OiPr)2(OiPr)4 type complex with a single chelating ligand, two bridging isopropoxo ligands, and two terminal isopropoxo groups on each of the two metal centers, which are of trigonal bi-pyramidal geometry.  相似文献   

19.
Chiral and achiral p-tert-butyl-calix[4]arene bisphosphites (L1L3) have been synthesized by the reaction of p-tert-butyl-calix[4]arene and the phosphorodichloridites, ROPCl2 [R = (1S,2R,5R)-(+)-iso-menthyl (L1), (1R,2S,5R)-(−)-menthyl (L2) or C6H4But-4 (L3)]. These bisphosphites function as chelating ligands in palladium(II) and platinum(II) complexes which are formed in good yields by the reaction of PdCl2(PhCN)2, MCl2(COD) (M = Pd or Pt) or PdMeCl(COD) with the respective calix[4]arene bisphosphite. Single crystal X-ray diffraction studies performed on the complexes [PdCl2(L1)], [PdCl2(L2)], [PdCl2(L3)] and [PtCl2(L3)] reveal a near square planar geometry around the metal with the two chloride ligands in a cis disposition. The crystal packing in the complexes [PdCl2(L1)] and [PdCl2(L2)], which crystallize in the chiral (P6122) space group, shows different hydrophobic channels with intermolecular C–H?Cl hydrogen bonding. The complexes [PdCl2(L3)] and [PtCl2(L3)] are isostructural and the molecules in the crystal lattice are linked by intermolecular C–H?Cl and C–H?O hydrogen bonds.  相似文献   

20.
Four different types of new ligands Ar[COC(NOH)R] n (Ar=biphenyl, n = 1 H2L1; Ar=biphenyl, n = 2 H4L2; Ar=diphenylmethane, n = 1 H2L3; Ar=diphenylmethane, n = 2 H4L4; R=2-amino-4-chlorophenol in all ligands) have been obtained from 1 equivalent of chloroketooximes Ar[COC(NOH)Cl] n (HL1-H2L4) and 1 equivalent of 2-amino-4-chlorophenol (for H2L1 and H2L3) or 2 equivalent of 2-amino-4-chlorophenol (for H4L2 and H4L4). (Mononuclear or binuclear cobalt(II), nickel(II), copper(II) and zinc(II) complexes were synthesized with these ligands.) These compounds have been characterized by elemental analyses, AAS, infra-red spectra and magnetic susceptibility measurements. The ligands have been further characterized by 1H NMR. The results suggest that the dinuclear complexes of H2L1 and H2L3 have a metal:ligand ratio of 1:2; the mononuclear complexes of H4L2 and H4L4 have a metal:ligand ratio of 1:1 and dinuclear complexes H4L2 and H4L4 have a metal:ligand ratio of 2:1. The binding properties of the ligands towards selected transition metal ions (MnII, CoII, NiII, CuII, ZnII, PbII, CdII, HgII) have been established by extraction experiments. The ligands show strong binding ability towards mercury(II) ion. In addition, the thermal decomposition of some complexes is studied in nitrogen atmosphere.  相似文献   

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