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Polyhedron
Pergamon Press
Polyhedron

Pergamon Press

0277-5387

Polyhedron/Journal PolyhedronSCICCREI
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    Luminescence Cd(II) coordination compounds based on a semi-rigid tricarboxylic acid ligand for identifying metal cations, inorganic anions and organic solvents

    Hasi, Qi-MeigeMu, Xiao-TongSu, Xiao-HongWei, Yu-Mei...
    8页
    查看更多>>摘要：Highly effective recognition and detection of metal ions, anions and organic small molecules from water have attracted remarkable attention for environmental safety. Herein, a novel Cd-based coordination polymer [Cd(HL) (4,4'-bipy)(H2O)](n) (1) and a metal-organic framework {[Cd-3(L)2(bip)(2)(H2O)(3)].5H(2)O}(n) (2) have been synthesized by employing a semi-rigid tricarboxylic acid ligand (H3L) and different N-containing ligands under hydrothermal conditions, where H3L = 3-[(1-carboxynaphthalen-2-yl)oxy] phthalic acid, 4,4'-bipy = 4,4'- bipyridine, bip = 1,4-di(pyridine-4-yl) benzene. Single crystal X-ray analysis reveals that 1 presents a 4 -connected 2D network structure with a Schlali symbol of (44.62),whilst 2 possesses a (3,4,4)-connected 3D framework with a Schlafli symbol of (4.82)2(42.82.102)(8.104.12). Furthermore, 1 and 2 have been characterized by elemental analyses, FT-IR, powder X-ray diffraction, thermogravimetric analyses, fluorescence and UV spectra, exhibiting good stability and excellent photoluminescence properties. 1 and 2 have been chosen as fluorescent probes to sense different target analytes, showing an obvious selective recognition response to Co2+, Ag+, Cr(2)O7(2)(-), CrO42-, nitrobenzene and nitromethane through luminescence quenching effects in aqueous solutions. The possible fluorescence quenching mechanisms are studied in detail, revealing that fluorescence quenching is mainly related to weak interactions, competitive energy absorption and electron transfer.
      原文链接:
    • NSTL
    • Elsevier

    Combining a weak-field rigid chelating bidentate dicarbene ligand with a strong-field carbonyl ligand in binuclear cyclopentadienyliron carbonyl derivatives

    Balaiu, CosminLupan, AlexandruKing, R. Bruce
    7页
    查看更多>>摘要：Binuclear cyclopentadienyliron carbonyl derivatives of the weak-field rigid chelating bidentate dicarbene vegi(Me) ligand with a tricyclic backbone are shown by theoretical studies on the Cp2Fe2(vegi(Me))(CO)(n) (n = 3, 2, 1) systems to have higher spin triplet and quintet structures of comparable energies to isomeric singlet structures satisfying the 18-electron rule. Thus triplet structures of the tricarbonyl Cp2Fe2(vegi(Me))(CO)(3) with the vegiMe ligand as a bidentate chelate to a single iron atom are of comparable energies to singlet isomers with no iron-iron bond and the vegi(Me) ligand bridging the two iron atoms. Similarly, triplet and quintet structures for the dicarbonyl Cp2Fe2(vegi(Me))(CO)(2) are of comparable energies to singlet structures with Fe-Fe single bonds that are substitution products of the well-known Cp2Fe2(CO)(2)(mu-CO)(2). The only low-energy singlet structure for the monocarbonyl Cp2Fe2(vegi(Me))(CO) has an unusual six-electron donor bridging vegiMe ligand forming not only the usual two C(carbene)-> Fe dative bonds but also a N -> Fe dative bond. The other low-energy Cp2Fe2(vegi(Me)) (CO) structures are various types of triplet and quintet spin state structures.
      原文链接:
    • NSTL
    • Elsevier

    An approach towards modification of UiO-type MOFs with phosphonate-substituted porphyrins

    Birin, Kirill P.Shlykov, Ivan, VSenchikhin, Ivan N.Demina, Liudmila, I...
    7页
    查看更多>>摘要：The post-modification of UiO-type materials with a porphyrin bearing phosphonic acid moieties is reported for the first time. The prolonged interaction of UiO-66 and tetrakis(4-phosphonatophenyl)porphyrinato nickel(II) Ni (H8-TPPP) resulted in the formation of a hybrid material with the preservation of the crystallinity of the material. The measured specific surface area of Ni(H8-TPPP@UiO-66) showed considerable decrease of the corresponding value in comparison with the starting UiO-66 (from 1181 to 619 m2/g), providing indirect proof of the localization of the porphyrin at the surface of the material crystallites. The prepared hybrid material was excessively characterized with a set of physical-chemical methods. The preservation of the thermal stability up to 400 degrees C is revealed, moreover the thermogravimetric data allowed to evaluate the ratio of the grafted porphyrin as ca. 18% by weight. UV-vis reflectance data of the hybrid material were found to be in consistency with the spectra of the starting porphyrin allowing to assume the absence of its intermolecular interactions at the surface of UiO. The analysis of the FT-IR spectra of the obtained material and its precursors allowed assuming the binding motifs of the phosphonic acid residues.
      原文链接:
    • NSTL
    • Elsevier

    Synthesis, characterization, crystal structures and thermochemical properties of five lanthanide complexes with mononuclear and binuclear structures

    Geng, ShuoRen, NingZhang, Jian-Jun
    9页
    查看更多>>摘要：Five new lanthanide complexes were synthesized by two different experimental methods: two mononuclear complexes and three binuclear complexes. Their chemical formula is: [Gd(2-Cl-4-FBA)(3)(terpy)H2O]1.5H(2)O(1); [Dy(2-Cl-4-FBA)(3)(terpy)H2O].0.5H(2)O(2)) (2-Cl-4-FBA = 2-chloro-4-fluorobenzoate,terpy = 2,2':6',2 ''-terpyridine); [Ln(3,4-DFBA)(3)(5,5'-DM-2,2'-bipy)(H2O)](2)(Ln = Pr(3),Er(4);[Ln(3,4-DFBA)(3)(5,5'-DM-2,2'-bipy)](2)(Ln = Ho(5)) (3,4-DFBA = 3, 4-difluorobenzoate,5,5'-DM-2,2'-bipy = 5,5'-dimethyl-2,2'-bipyridine). A series of characterization and properties of the complexes were studied, such as elemental analysis, single crystal X-ray diffraction, thermogravimetric analysis, fluorescence properties and so on. The coordination number of complexes 1-2 is 9, showing a muffin geometry. The results show that complex 1-5 crystallized in the triclinic system and space group P(i)over bar . Complexes 1 and 2 are isostructural except for the number of free water molecules. Complexes 3-5 are binuclear molecules with different structures. Although the structures of the five complexes are different, they all form one and two-dimensional supramolecular structures along a chain and a plane. The thermal decomposition mechanism of complexes 1-5 was studied by synchronous thermal analyzer infrared spectroscopy (TG/DSC-FTIR). The results show that the coordination water, neutral ligand and acidic ligand are lost in turn when the complex undergoes thermal decomposition. And the three-dimensional infrared images of gas escaping during the thermogravimetric process were analyzed. In addition, the solid state fluorescence spectra of complex 2 was measured and the results showed that the characteristic fluorescence of Dy(III) ion was emitted.
      原文链接:
    • NSTL
    • Elsevier

    Gold(III) heteroleptic complexes with SNS-thiosemicarbazonate ligands as cytotoxic agents: Experimental and computational insights into the mechanism of action

    da Silva, Amandha KaiserSantos, Mal MateusCandido, Pamela Aparecidade Oliveira Lopes, Erica...
    11页
    查看更多>>摘要：New gold(III) heteroleptic complexes of general formula [AuX(dmtsc)], with (dmtsc)(2-) = (dieth-ylaminothiocarbonyl)benzimidoyl-morpholinyl-thiosemicarbazonate and X = xant(-) (ethyl xanthate) or damp- (dimethyl-1-phenylmethanamine), were synthesized and compared to the chlorido precursor [AuCl(dmtsc)]. The characterization of the new complexes included FTIR, elemental analysis, molar conductivity, UV-Vis, H-1 and C-13 NMR spectroscopies and ESI(+)-MS. In addition, the xanthate derivative was analyzed by single-crystal X-ray diffraction. In vitro assays against three tumor cell lines (B16-F10, HCT-8 and MDA-MB-231) showed that the gold(III) complexes display remarkable antiproliferative effects on human breast adenocarcinoma cell line with influence of the co-ligands. The cytotoxicity on VERO cells was also investigated revealing that the organome-tallic complex [Au(damp)(dmtsc)] was the most selective compound for MDA-MB-231, although not the most active. Attempting to comprehend their behavior in biological medium, studies involving the interactions with possible biological targets were performed by experimental methods and theoretical docking simulations. Their results indicated that HSA might be a probable carrier of the compounds in the biological medium, whereas DNA is not supposed to be their main target. On the other hand, all compounds totally inhibited thioredoxin reductase enzyme (TrxR) at the concentration of 50 mu M and formed significant molecular interactions, suggesting that it might be one of the molecular targets of these gold(III) complexes.
      原文链接:
    • NSTL
    • Elsevier

    Synthesis and characterization of Merrifield resin-supported vanadium complexes for the catalytic oxidation of straight-chain aliphatic alcohols

    Kesharwani, NehaHaldar, Chanchal
    12页
    查看更多>>摘要：Two Schiff-base ligands [hynd-ap] (I) and [hynd-ae] (II) were prepared by reacting 2-hydroxynapthaldehyde with 2-aminophenol and aminoethylethanolamine, respectively. By systematically using the prepared Schiff base ligands (I) and (II), a number of vanadium(IV) and (V) complexes were prepared and thoroughly characterized. Single crystal X-ray analysis, UV-Vis, FT-IR spectra and mass studies indicate that both the dioxidovanadium(V) complexes [VO2(hynd-ap)] (4) and [VO2(hynd-ae)] (5) exist in the monomeric form in the solid-state as well as in solution. The dioxidovanadium(V) complexes 4 and 5 were grafted on imidazole modified chloromethylated polystyrene, giving PS-im-[VO2(hynd-ap)] (6) and PS-im-[VO2(hynd-ae)] (7), for application in the catalytic oxidation of a series of primary aliphatic alcohols. Both the supported catalysts showed excellent catalytic performance towards this range of alcohols. A maximum of 98% substrate conversion to 1-proponal was observed in the presence of 6. Irrespective of the substrate, catalyst 6 shows better substrate conversion than 7 under the optimized reaction conditions. It has been observed that the catalytic performance of both the supported catalysts reduces slightly on increasing the number of carbon atoms in the alcohols, except for EtOH.
      原文链接:
    • NSTL
    • Elsevier

    Biologically active Cu(II), Ni(II) & Co(II) complexes of a tridentate N, O, O-donor Schiff base from citral and L-alanine: Synthesis, characterization and antimicrobial activity

    Bencela, M.Kumari, S. Sudha
    11页
    查看更多>>摘要：The intramolecular hydrogen-bonded N, O, O-donor Schiff base ligand (L1), which is derived from citral (3,7-dimethyl-2,6-octadienal, C10H16O) and L-alanine, has been used to synthesize a series of Cu(II), Ni(II), and Co(II) complexes (1, 2 & 3). Elemental analysis, spectroscopic techniques, magnetic susceptibility tests, and thermal analysis were used to characterize these complexes. Complexes 1 and 3 have a distorted square pyramidal ge-ometry with the N, O, O donor (azomethine nitrogen and mu 2-carboxylato oxygen atoms) Schiff base, L1, in which the adjacent M(II) ions are coupled in an equatorial-axial pattern by the carboxylate unit of L1 and display ferromagnetic interaction. However, complex 2 displays distorted octahedral geometry with significant anti-ferromagnetic interactions between neighboring Ni(II) ions via a bridged carboxylate unit in an equatorial-axial manner. The octahedral geometry of complex 2 is further supported by analyses of ligand field parameters and theoretical magnetic susceptibility studies. The antimicrobial activities of L1 and its complexes were screened against bacteria (AR) and fungus. The findings suggest that M(II) complexes of L1 have the potential to be employed in the development of antibacterial and antifungal drugs.
      原文链接:
    • NSTL
    • Elsevier

    Zn(II) coordination polymer with p-stacked 4,4 '-bipyridine dimers: Synthesis, structure and luminescent properties

    Demakov, Pavel A.Ryadun, Alexey A.Fedin, Vladimir P.
    5页
    查看更多>>摘要：A new metal-organic coordination polymer [Zn-2(bpy)(2)(NO3)(2)(chdc)] (1; bpy = 4,4'-bipyridine, chdc(2-) = trans-1,4-cyclohexanedicarboxylate) was synthesized and characterized. This compound is based on the nitrate-capped binuclear {Zn-2(N-bpy)(4)(NO3)(2)(OOCR)(2)} fragments interconnected by dicarboxylate moieties and pi-stacked bpy dimers with ca. 3.53 angstrom interplanar distance to form a two-dimensional (2D) sql network. Thermal and luminescent properties of 1 were investigated. Under excitation from 320 nm to 480 nm, the named compound demonstrates wide-banded yellow emission with the red shift of the maximum from 562 nm to 596 nm, and quantum yields up to 6.7%.
      原文链接:
    • NSTL
    • Elsevier

    Synthesis, structure and hydrolysis studies of pseudostannatranes: Kinetic studies of a hexanuclear tin(IV) hydroxo-cluster formed via reverse Kocheshkov reaction and partial hydrolysis of pseudostannatrane

    Kumar, KeshavSingh, RaghubirKaur, Varinder
    9页
    查看更多>>摘要：The structural and synthetic aspects of novel mononuclear pseudostannatranes and a hexanuclear tin(IV) hydroxo-cluster have been reported. The reaction of the bis-phenolate aminoethanol tripodal ligand N (CH2CH2OH){CH2(2,4-di-t-Bu-C6H(2)OH)}(2) (H3L) with BuSnCl3, PhSnCl3 and SnCl4 yielded the mononuclear pseudostannatranes [N(CH2CH2O){CH2(2,4-di-t-Bu-C6H(2)O)}2Sn(n-Bu)H2O] (1), [N(CH2CH2O) {CH2(2,4-di-t-Bu-C6H(2)O)}(2)Sn(Ph)EtOH] (2) and [N(CH2CH2OH){CH2(2,4-di-t-Bu-C6H(2)O)}(2)Sn(Cl)(2)] (3), respectively. The reaction of the ligand with PhSnCl3 using triethylamine as a base produced the reverse Kocheshkov product [N (CH2CH2OH){CH2(2,4-di-t-Bu-C6H2O)}2Sn(Cl)2].1/3NEt3 (3.1/3NEt3), which on partial hydrolysis yielded the hexanuclear tin(IV) hydroxo-cluster [N(CH2CH2O){CH2(2,4-di-t-BuC6H(2)O)}2SnCl](2){(OH)(3)SnPh(OH)(2)SnPh (OH)3}[SnN(CH2 CH2O){CH2(2,4-di-t-Bu-C6H(2)O)}(2)]2 (4). The synthesized compounds were characterized by elemental analysis, infrared spectroscopy, multi-nuclear NMR spectroscopy, electrospray ionization mass spectrometry and single-crystal X-ray diffraction. In addition, vital facts regarding the kinetics of the partial hy-drolysis of the reverse Kocheshkov product to form the hydroxo cluster were explained by Sn-119 NMR spectroscopy.
      原文链接:
    • NSTL
    • Elsevier

    A muconate bridged bipyridyl appended binuclear Cu(II) complex reveals dissimilar affinities to DNA and BSA protein

    Alam, Seikh MafizIslam, Md MaidulMir, Mohammad HedayetullahAhmed, Faruk...
    6页
    查看更多>>摘要：A new muconate based Cu(II) metal complex, [Cu-2(muco)(5,5'-Me(2)bpy)4].2ClO(4) butadiene-1,4-dicarboxylic acid or trans , trans-muconic acid and 5,5'-Me2bpy = 5,5'-dimethyl-2,2'-bipyridine), has been synthesized and structurally characterized. X-ray structure analysis reveals that 1 forms a binuclear complex with a five coordinated square pyramidal geometry of the central Cu(II) ion attached to a muco and two bipyridine ligands. Docking studies have been carried out which reveal the successful binding of the metal complex to the major groove of DNA and the planar aromatic bipyridyl ligand partially intercalates into the base pairs. The synthesized complex fits into the pocket of bovine serum albumin (BSA), while the maximum fraction submerges into the BSA binding pocket. An extra coordinate bond has been found, forming through the oxygen atom of 158 asparagines amino acid, which subsequently forms a new six coordinated octahedral complex. Experimental studies have been performed to validate all the data obtained from the docking studies. This study reveals highly diverse affinities and binding modes of the synthesized complex towards DNA and protein. Therefore, the synthesized complex may pave the way to be used as a specific protein binder (low affinity to DNA or RNA) bioactive compound.
      原文链接:
    • NSTL
    • Elsevier