Polymeric Chain Structure Research Articles

Carboxylic-supported copper complexes as catalyst for the green oxidative coupling of 2,6-dimethylphenol: Synthesis, characterization and structure

Abstract Three new Cu(II) complexes with carboxylic ligand, namely {[Cu(qc)2(py)]·4H2O}∞ (1), [Cu(qc)2(4,4′-bpy)]∞ (2) and [Cu(pc)(2,2′-bpy)(H2O)]2·H2O (3) (Hqc = 3-hydroxy-2-quinoxalinecarboxylic acid, H2pc = 4-hydroxyphthalic acid, py = pyrazine) have been synthesized and characterized. In both 1 and 2, each Cu(II) ion is coordinated by two quinoxalinecarboxylate moieties in the equatorial plane and two 4,4′-bpy or pyrazine units provide coordination in the axial positions, thus, resulting in a 1-D polymeric chain structure. Complex 3 has a dimeric structure in which two Cu(II) cations are bridged by two deprotonated pc2− ligands and two 2,2′-bpy molecules. As heterogeneous catalysts, the title complexes showed high catalytic efficiency in the green oxidative polymerization of 2,6-dimethylphenol (DMP) to poly(1,4-phenylene ether) (PPE) in the presence of H2O2 as oxidant in water under mild conditions. Moreover, they allow reuse without significant loss of activity through four runs, which suggests that these catalysts are efficient, mild, and easily recyclable for the oxidative coupling of DMP. The preliminary study of the catalytic–structural correlations suggests that the coordination environment of the metal center plays an important role in the improvement of their catalytic efficiencies.

The X-Ray Structure of 5-Chlorosalicylaldehyde

5-Chlorosalicylaldehyde [monoclinic, a = 3.800(2), b = 5.595(4), c = 15.174(11) A, β = 93.221(17)°, space group P21] exhibits an unusual crystal structure with both intramolecular and intermolecular OH to CH=O hydrogen bonding, the latter leading to chains of molecules aligned along the b axis. A survey of previous substituted salicylaldehyde structures shows three main hydrogen bonding patterns: intramolecular only (14), intramolecular and intermolecular dimeric (5), and intramolecular and intermolecular polymeric (3). 5-Chlorosalicylaldehyde adopts the rather uncommon polymeric chain structure with both intra- and intermolecular hydrogen bonding.

Syntheses and characterizations of di- and tri-organotin carboxylates of 4-oxo-4-phenyl butanoic and 4-(4-biphenyl)-4-oxobutyric acid

A family of organotin carboxylates, [(C6H5)3Sn(L1)2] (1) and [(C6H11)2Sn(L2)] (2), was synthesized from reaction of R3SnOH and (where R = phenyl, R′ = cyclohexyl) with 4-oxo-4-phenyl butanoic (L1H) and 4-(4-biphenyl)-4-oxobutyric acid (L2H) in suitable mole ratios. They have been characterized by elemental analysis, FT-IR, 1H NMR spectroscopy, and single-crystal X-ray diffraction analysis. In 1, the geometry of tin is trigonal bipyramidal. Supramolecular architecture of 1 shows a polymeric chain structure with Ph3Sn centers linked by PhCOC2H4CO2 ligands via O → Sn interactions. Sn···Sn non-bonded distances in the repeating 1-D polymeric structure equal 5.835 Å. Complex 2 contains an angular sector and adopts a distorted tetrahedral geometry.

Di- and tri-organotin(IV) complexes with 2-hydroxy-1-naphthaldehyde 5-chloro-2-hydroxybenzoylhydrazone: Synthesis, characterization and in vitro antitumor activities

Series of new organotin(IV) complexes of the types R2SnL, R is Me (1), Ph (2), o-Cl–C6H4CH2 (3); and [R3SnL]∞, R = n-Bu (4) (H2L = 2-hydroxy-1-naphthaldehyde 5-chloro-2-hydroxybenzoylhydrazone) have been synthesized and structurally characterized by means of elemental analysis, FT-IR, UV–vis spectroscopy, NMR (1H, 13C and 119Sn) spectra and X-ray single crystal diffraction analyses. Structural analyses reveal that complexes 1–3 show similar monomeric structure, in which the tin center is coordinated with the enolic tridentate ligand (L) in the ONO chelate mode and exhibits five-coordinated trigonal bipyramidal geometry. Unexpectedly, complex 4 presents as a rare one-dimensional chain polymeric structure, in which the coordination of Sn is also five-coordinated trigonal bipyramidal geometry and the segment of tri-n-butyltin is bridged by the de-protonated phenolate O atom and the carbonyl O atom from the non-enolic Schiff base ligand. All compounds exhibit good in vitro antitumor activity toward human colon cancer cells (HCT-8), lung cancer cells (A549) and human promyelocyticfina leukemic cells (HL-60). The results indicate that both alkyl groups bound with tin centers and the structural of organotin compounds have significant effect on their in vitro antitumor activities. Among them, the polymeric tri-n-butyltin Schiff base complex 4 is the most active one, and the complex 3 shows high selectivity on the tumor cells HCT-8 and HL-60. For all of the title compounds, there was a good dose–effect relationship.

Catena-Poly[(μ-anilido)(μ-1,2-dimethoxyethane-κ3-O,O′:O)sodium

In the title compound, [Na(C6H5NH)(C4H10O2)], the Na+ cation is coordinated by the N atoms of two anilide anions, two O atoms of a chelating 1,2-dimeth­oxy­ethane (dme) ligand and one O atom of an adjacent dme ligand. The coordination polyhedron around Na+ corresponds to a distorted square pyramid with the N atoms of the anilide groups and the O atoms of the chelating dme unit at the base and a third O atom at the apical position. The anilide anions act as μ-bridging ligands and the 1,2-dimeth­oxy­ethane mol­ecules display a μ2-κ3-O,O′ coordination mode. As a result of this connectivity, a polymeric chain structure parallel to [100] is formed, consisting of Na2O2 and Na2N2 four-membered rings. It should be noted that the remaining H atom of the anilide NH group is not involved in hydrogen bonding.

Catena-Poly[[[(1,10-phenanthroline-κ2N,N′)praseodymium(III)]-di-μ-4-hydroxybenzoato-κ4O1:O1′-μ-nitrato-κ3O,O′:O] bis(1,10-phenanthroline)

The title complex, [Pr(C7H5O3)2(NO3)(C12H8N2)]·2C12H8N2, has a polymeric chain structure, with two uncoordinated 1,10-phenanthroline mol­ecules in the lattice. The PrIII centre has a monocapped square-anti­prismatic coordination geometry, comprised of two N atoms from one chelating 1,10-phenanthroline ligand, four carboxyl­ate O atoms from four 4-hy­droxy­benzoate anions and three O atoms from two nitrate anions. The 4-hy­droxy­benzoate and nitrate anions function as μ2-bridging ligands and link the PrIII ions into a one-dimensional chain structure along the c axis. Inter­molecular O—H⋯N hydrogen bonds are observed between the 4-hy­droxy­benzoate anions and the uncoordinated 1,10-phenanthroline mol­ecules.

Crystal structures and thermodynamic properties of lanthanide complexes with 2-chloro-4,5-difluorobenzoate and 1,10-phenanthroline

A series of lanthanide complexes with the 2-chloro-4,5-difluorobenzoate (2-cl-4,5-dfba) and 1,10-phenanthroline (phen), have been synthesized with the formulae of [La(2-cl-4,5-dfba)3phen]n·nH2O (1), [Nd(2-cl-4,5-dfba)3phenH2O]2 (2), [Ln(2-cl-4,5-dfba)3phen]2 (Ln=Eu (3), Ho (4)). The complexes are characterized by elemental analysis, infrared and fluorescent spectra and X-ray single-crystal diffraction. The structures of the four complexes are very different. Complex 1 is an infinite 1D chain polymeric structure formed by the asymmetric units with the mirror growth pattern. Each La3+ ion is coordinated to four bridging carboxylic groups, two tridentate chelating–bridging carboxylic groups, simultaneous with one phen molecule, giving the coordination number of nine. In the molecular structures of complexes 2 and 3, two Ln3+ ions are linked by four carboxyl groups, forming two binuclear molecules. In addition, each Nd3+ ion in complex 2 is bonded to one H2O molecule and one carboxyl group by monodentate mode, one phen molecule by bidentate chelating, and each Eu3+ ion is also chelated to one phen molecule and one carboxyl group in complex 3. And in complex 4, the Ho3+ ion yields a eight-coordinated distorted square anti-prism coordination geometry. The three-dimensional IR accumulation spectra of gaseous products for complexes 1 to 4 are analyzed and further authenticated the thermal decomposition processes with TG-DTG curves. The heat capacities of complexes 2 to 4 are measured and fitted to a polynomial equation by the least squares method on the basis of the reduced temperature x (x=[T−(Tmax+Tmin)/2]/[(Tmax−Tmin)/2]). Then the smoothed molar heat capacities and thermodynamic functions of complexes 2 to 4 are calculated. The fluorescence intensity of complex 3 is markedly improved as well.

Synthesis and Crystal Structure of a New Copper(II) Coordination Polymer [CuC<sub>16</sub> H<sub>18</sub> N<sub>4</sub>O<sub>4</sub>S]<sub>n</sub>*

A new one-dimensional [CuC16H18N4O4S]n(1) was synthesized by the self-assembly of a ligand 2,5-thiophenediformates, 3,5-dimethylpyrazole and copper(II), and characterized by elemental analysis, IR and single-crystal X-ray diffraction. 1 crystallizes in monoclinic, space group C2/c with unit cell parameters, a=18.6156(4), b=5.96110(10), c= 18.1598(4)Å, =115.467(2)°, Z=4, V=1819.37(7)Å3, Mr = 425.94, Dc = 1.555g/cm3, μ=1.345mm-1, and F(000)= 876. The final R and wR are 0.0328 and 0.0816 for 7611 observed reflections with I>2σ(I). 1 shows an infinite 1-D polymeric chain structure based on the repeated basic units Cu(II)(3,5-dimethylpyrazole)2(2,5-thiophene diformate). The Cu(II)center acts as the joint of the unit, and is coordinated in a slightly distorted octahedral geometry comprised of four O atoms from two different 2,5-thiophenediformate ligands and two N atoms of two trans 3,5-dimethylpyrazole ligands.

Charge-Assisted Complexation of Anions of Different Dimensionality by Benzimidazole-Based Receptors Bearing -OH Functionality

Two benzimidazole-based receptors (L1 and L2) bearing -OH functionality form crystalline salts with different organic and inorganic acids viz. [L1H+][Cl–] (1), [L1H+][NO3–] (2), [L1H+][OAc–] (3), [L1H+][DNB–]·DMF (4), [L1H+][H2PO4–] (5), [L2H+][OAc–]·AcOH (6), [L2H+][DNB–] (7), and [L2H+][HSO4–]·H2O (8) where the shape of the counteranion drives the solid structure from a one-dimensional polymeric chain to a three-dimensional structure. Structural analyses show that the anion binding in all eight complexes is attributable entirely to NH+···anion, NH···anion, OH···anion, and multiple CH···anion hydrogen bonding interactions. In the solid structure the planar nitrate anion forms a cyclic structure with receptor L1, whereas the acetate anion with the same receptor leads to a molecular barrel type structure. Again the tetrahedral dihydrogen phosphate anion forms a polymeric interanionic chain structure with L1, and the other tetrahedral hydrogen sulfate anion forms hydrogen sulfate–(water)2–hydrogen sulfate adducts with charged L2.

Design and construction of six metal–organic frameworks with 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylate

Six novel transition-metal–organic frameworks, [Cu(μ2-HMOPhIDC)(H2O)]n (H3MOPhIDC = 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylic acid) (1), [Zn(μ2-HMOPhIDC)(2,2′-bipy)]n (2,2′-bipy = 2,2′-bipyridine) (2), [Co(μ2-HMOPhIDC)(2,2′-bipy)]n (3), [Co(μ2-HMOPhIDC)(phen)]n (phen = 1,10-phenanthroline) (4), [Cd1.5(μ2-H2MOPhIDC)(μ3-HMOPhIDC)(H2O)]n (5) and {[Co1.5(μ2-H2MOPhIDC)(μ3-HMOPhIDC)(py)]·2H2O}n (py = pyridine) (6) have been successfully synthesized under hydrothermal conditions, and characterized by means of elemental analyses, IR and single-crystal X-ray diffraction. The organic ligand H3MOPhIDC can be singly deprotonated or doubly deprotonated, and coordinate to metal ions in various modes. Polymers 1–4 display an infinite polymeric chain structure connected by μ2-HMOPhIDC2− ligands, but show different crystal packing fashions. Polymers 5 and 6 exhibit two-dimensional sheet structures built from double-stranded chains. The thermal properties of polymers 1–6 and luminescence properties of 2 and 5 have been determined. Also, the magnetic properties of polymers 1, 3, 4 and 6 have been investigated.

Preparation of a Daisy Chain via Threading-Followed-by-Polymerization

A daisy chain, a linear array of self-complementary (plerotopic) molecules linked together by mechanical bonds, was prepared by polyesterification of two complementary host–guest units based on the dibenzo-24-crown-8/1,2-bis(pyridinium)ethane recognition motif conveniently via “threading-followed-by-polymerization”, an approach different from the formerly reported method, in which mechanically interlocked monomers were first prepared and then polymerized, used in the construction of this kind of polymers. It was characterized by various techniques including 1H NMR, COSY, NOESY, GPC, TGA, dynamic laser light scattering (DLS), UV–vis, and viscosity. Its molecular weight Mn was 64 kDa with polydispersity of 1.5 as determined by GPC, indicating that 45 repeating units existed in a single polymer chain. Its hydrodynamic diameter in a dilute acetonitrile solution was about 250 nm as determined by DLS. These studies not only proved the successful fabrication of the desired daisy chain polymeric structure but als...

Bismuth(III) Saccharinate and Thiosaccharinate Complexes and the Effect of Ligand Substitution on Their Activity against Helicobacter pylori

Five bismuth(III) saccharinate and thiosaccharinate complexes, [Ph2Bi(sac)]∞1, [Bi(sac)3]n2, [Ph2Bi(tsac)]∞4, [PhBi(tsac)2]n5, [Bi(tsac)3]n6 (sacH = saccharin, tsacH = thiosaccharin), have been synthesized and fully characterized. The tendency for ligand redistribution in [Ph2Bi(sac)]∞ has been investigated in solution by NMR spectroscopy. The structures of [Ph2Bi(sac)]∞1 and [Ph2Bi(tsac)]∞4 have been confirmed by X-ray crystallography. In Ph2Bi(sac) the sac ligand is bound to a four-coordinate bismuth center via its imino nitrogen atom with an accompanying long-range Bi–O interaction. However, in the structure of [Ph2Bi(tsac)]∞ the ligand is σ-bound through the exocyclic sulfur atom, giving a thiolate complex, confirming the more thiophilic nature of bismuth(III). Both complexes consist of polymeric chain structures with formally four-coordinated bismuth atoms. The complexes were assessed for their activity against H. pylori. The activity is both ligand dependent and sensitive to the degree of ligand substitution. The saccharinate complexes, 1 and 2, show activity comparable with standard tris-carboxylato bismuth(III) compounds, 6.25 μg/mL, while the activity of the thiolato complexes, 4–6, increases dramatically on increasing the number of thiolate groups from one to three (range 50–6.25 μg/mL). Saccharin, thiosaccharin, and BiPh3 were found to be inactive.

Syntheses and characterization of diorganotin(IV) derivatives with areneseleninic acid: X-ray crystal structures of 1D infinite chains containing eight-membered ring

Three new diorganotin(IV) complexes, [Bu 2Sn(O 2SeC 6H 5) 2] n ( 1), [Bu 2Sn(O 2SeC 6H 4Me) 2] n ( 2), [Me 2Sn(O 2SeC 6H 4Bu) 2] n ( 3) have been synthesized by the reaction of benzeneseleninic acid, p-tolueneseleninic acid, and 4- tert-butylbenzeneseleninic acid with Me 2SnCl 2 or Bu 2SnCl 2 in the presence of sodium ethoxide in methanol at 50 °C. All of the complexes were characterized by elemental analysis, FT-IR, NMR ( 1H, 13C and 119Sn) spectroscopy and X-ray crystallography. X-ray diffraction studies of 1, 2, 3 show that the areneseleninate groups behave as double bridges between the tin atoms leading to polymeric chain structure with Sn 2O 4Se 2 eight-membered ring. The organic groups bonded to the tin atoms are in trans-position in the resulting octahedral arrangement.

Two new coordination polymers constructed by angular tripyridyl ligand: syntheses, structures, and properties

U-shaped tripyridyl ligand 2,6-bis(pyridine-4-carboxamido)pyridine (L) was synthesized and used to assemble metal complexes. The resulting new complexes [Mn(L)3(SCN)2] n (1) and [Co(L)3(SCN)2] n (2) are isostructural, crystallizing in the monoclinic C2/c space group. In compounds 1 and 2, each metal is in a slightly distorted octahedron ligated by six nitrogens from four L and two SCN−. Complexes 1 and 2 possess infinite 1-D zigzag polymeric chain structures where L adopts bridge and terminal coordination. These 1-D coordination polymers assemble into 3-D supermolecules of compounds 1 and 2 through hydrogen bonds. Fluorescence measurements and thermal analysis show that 1 emits strong fluorescence with a single broad band centered at 410 nm upon excitation at 357 nm and the polymeric chain structure is stable up to 340°C.

Synthesis and characterization of polymeric triphenyltin and cyclotetrameric tricyclohexyltin 2-(1H-imidazol-1-yl)acetates

The reaction of 2-(1H-imidazol-1-yl)acetic acid with (Ph3Sn)2O or Cy3SnOH (Cy = cyclohexyl) yields triphenyltin 2-(1H-imidazol-1-yl)acetate (1) and tricyclohexyltin 2-(1H-imidazol-1-yl)acetate (2), respectively. 2-(1H-imidazol-1-yl)acetates in these two complexes show remarkably different coordination modes. Complex 1 forms a polymeric chain structure through intermolecular Sn–N interactions, while 2 displays a 28-membered macrocyclic tetranuclear structure by the assembly of Sn–N coordination bonds.

Synthesis, spectroscopy and magnetic properties of transition-metal complexes with aminophosphonate derivatives of pyridine

The compounds of general formula [ML2](ClO4)2 [M = Cu(II), Ni(II), Co(II)]; L = diethyl 3-pyridylmethyl[N-(butyl)amino]phosphonate (3-pmape) or diethyl 4-pyridylmethyl[N-(butyl)amino]phosphonate (4-pmape) were prepared. The new complexes were identified and characterized by elemental analysis, infrared, electronic spectral studies and magnetic measurements. The complexes are sixcoordinate. Metal ions are octahedrally surrounded by two pyridine and two amine nitrogens, and two oxygens of the phosphoryl groups. The results of the magnetic studies suggest polymeric chain structure of the above complexes and indicate weak antiferromagnetic interaction between the magnetic centers. The magnetic behavior of Co(II) complexes is characteristic for cobalt(II) system with an important orbital contribution via spin-orbit coupling.

Syntheses and Structural Characterization of Three New Alkaline Earth Metal Supramolecular Coordination Compounds Based on Atza Ligand (Atza = 5-Aminotetrazole-1-Acetato Anion)

Reactions of alkaline earth metal salts M(NO3)2 (M = Mg, Ca, Sr) and ligands 5-aminotetrazole-1-acetic acid (Hatza) in water/methanol solution, respectively, produced three new complexes [Mg(atza)2(H2O)4] (1), [Ca(atza)2(H2O)4] (2) and [Sr(atza)2(H2O)3].2H2O (3). These compounds were structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Compounds 1 and 2 have a mononuclear structure and the same coordination mode. Compound 3 has a 1D polymeric chain structure. In 1–3, amido group (–NH2) of atza ligand forms hydrogen bond N(5)–H(5)···N(O) with the neighboring carboxylate-O, tetrazolate-N or water molecule which stabilized the supramolecular assemblies.

Poly[bis[μ2-(dimethylazaniumyl)methylenediphosphonato]magnesium

The title compound, [Mg(C3H10NO6P2)2]n, synthesized by a hydro­thermal method, adopts a one-dimensional polymeric chain structure and is isotypic with the previously reported Cd complex based on the ligand N,N-dimethyl­amino­methane-1,1-diphospho­nic acid (H4 L). The asymmetric unit contains one half Mg2+ ion and one H3 L − anion. The unique Mg2+ ion lies on an inversion center and is octa­hedrally coordinated by O atoms from six phospho­nate groups of four different H3 L − anions. Each H3 L − anion, with one protonated N atom and two phospho­nate OH groups, serves as a tridentate ligand. Two of its six phospho­nate O atoms chelate to a Mg2+ cation in a bidentate fashion, while a third O atom bridges to a neighbouring Mg2+ ion. The inter­connection of Mg2+ ions by the H3 L −anions leads to the formation of a polymer chain along the a axis in which the adjacent Mg2+ ions are doubly bridged by two equivalent H3 L − anions. These discrete chains are further assembled into a three-dimensional supra­molecular network via O—H⋯O and N—H⋯O hydrogen bonds involving the non-coordin­ated phospho­nate O atoms and the protonated N atoms.

Two yttrium(III) coordination compounds containing a3-ptz or atza [a3-ptz = 5-[N-acetato(3-pyridyl)]tetrazole; atza = 5-aminotetrazole-1-acetato

Two yttrium(III) coordination compounds, [Y(a3-ptz)2(H2O)5]Cl · 4H2O (1) and [Y(atza)2(H2O)2(CH3OH)]Cl (2) [a3-ptz = 5-[N-acetato(3-pyridyl)]tetrazole; atza = 5-aminotetrazole-1-acetato], have been synthesized. Single-crystal X-ray diffraction analysis reveals that 1 has a distorted monocapped square-antiprism coordination geometry around YIII. Complex 2 is a distorted pentagonal bipyramid with coordination from four atza ligands, two waters, and one methanol; the coordination of atza in 2 leads to its 1-D polymeric chain structure. 1 and 2 are self-assembled to form 3-D supramolecular structures through hydrogen bonds. The luminescence properties of 1 and Ka3-ptz were investigated at room temperature in the solid state.

Synthesis and structural characterization of mixed-metal complexes of CuI with MOS3 cores (M = Mo, W) and of an unusual polymeric AgI/mercaptoimidazole complex with five different AgI coordination environments

Reaction of (NH(4))(2)[MO(2)S(2)] (M = Mo or W) with KI, CuCl and 1,3-diazepane-2-thione (Diap) in acetone affords air- and moisture-stable mixed-metal cluster compounds [MOS(3)(CuDiap)(3)]I (1 and 2). Attempts to produce [WS(4)Ag(2)(Mim(Ph))(4)] (Mim(Ph) = 2-mercapto-1-phenylimidazole) led to the unexpected polymeric compound [Ag(5)I(5)(Mim(Ph))(4)](n) (4), subsequently obtained from a rational direct reaction between AgI and Mim(Ph) in chloroform. The complexes have been characterized by IR, (1)H and (13)C NMR spectroscopy, and single-crystal diffraction. 1 and 2 have crystallographic threefold rotation symmetry, with an incomplete distorted cube MS(3)Cu(3) core bearing terminal oxo and Diap ligands on M and Cu, respectively. The cube vertex opposite M is empty, giving an overall +1 cationic cluster and a separate I(-) anion too distant from the three Cu atoms to be considered as covalently bonded and resulting in discrete ion pairs in the crystal structures. This arrangement is different from previously reported related OMS(3)(CuL)(3)X complexes (L = monodentate ligand, X = halide), in which X, when present, is directly bonded to one, two or three Cu atoms. 4 has a one-dimensional polymeric chain structure in which silver displays five different approximately tetrahedral coordination environments, iodide ions serve as μ(2), μ(3) and μ(4) bridges, and the thione ligands are each either terminal or bridging. This unusually complex structure for a relatively simple chemical formula represents only the fifth example of a complex (AgI)(n)L(m) in which L is a neutral S-donor ligand, and the five structures display a wide range of individual features. In all three of the new structures, N-H···S and/or N-H···I hydrogen bonds are found.