Zn Polymers Research Articles

Unusual Polymeric ZnII/CdII Complexes with 2,6-Diaminopurine by Synergistic Coordination of Nucleobases and Polycarboxylate Anions: Binding Behavior, Self-Assembled Pattern of the Nucleobase, and Luminscent Properties

To investigate the coordination behavior of 2,6-diaminopurine (Hdap) and to construct unique high-dimensional nucleobase-based complexes, six Hdap-based ZnII/CdII polymers were obtained by incorporating aliphatic/aromatic polycarboxylate as coligands under hydrothermal conditions and were fully structurally characterized. Significantly resulting from the synergistic coordination of nucleobase and polycarboxylate groups, they are a tetranuclear ZnII-core-based two-dimensional (2D) covalent layer for {[Zn4(μ2-Hdap)2(tp)3(μ3-OH)2]·2H2O}n (1), an eight-connected three-dimensional (3D) self-penetrating metal−organic framework (MOF) for [Zn2(μ2-Hdap)(tp)2]n (2), a 3D pillared-layer structure for {[Zn2(μ2-Hdap)(tm)(μ2-OH)]·H2O}n (3), a one-dimensional (1D) linear double-chain motif for {[Zn(H2dap)(H2O)(btc)]·3H2O}n (4), a trinuclear CdII-cluster-based 2D aggregate for {[Cd3(H2O)2(μ3-dap)2(ap)2]·H2O}n (5), and a 1D Z-shaped chain for {[Cd(H2dap)(H2O)2(tp)]·0.5tp·H2O}n (6), respectively (H2tp = terephthalic acid, ...

Polymeric Zn(II) and Cu(II) complexes with exobidentate bridging l-tyrosine: Synthesis, structural and spectroscopic properties

A novel zinc(II) polymeric complex of the formula {[Zn(tyr) 2(H 2O)]H 2O} n ( 1) containing l-tyrosine (tyr) was prepared in the crystalline form and characterized by X-ray diffraction, NIR–Vis–UV electronic and IR–FIR vibrational spectroscopy methods. Additionally, for the [Cu(tyr) 2] n ( 2) polymer, the vibrational, electronic, EPR spectroscopic and magnetic properties were studied. l-tyrosine in coordination polymers acts as a N,O-bidendate ligand and presents exobidentate bridging with a μ-carboxyl group. The μ-carboxyl exobidentate bridging coordination mode leads to a one-dimensional chain structure. The ZnN 2O 3O′ chromophore has an elongated pseudo-octahedral geometry ( 1), whereas the CuN 2O 2O′ ( 2) chromophore presents a distorted square-pyramidal environment with τ = 0.19 around the Cu 2+ ion.

Polymeric frameworks constructed from Zn with benzenetricarboxylic acid ligands and monodentate 4,4′-bipyridine: hydrothermal synthesis, crystal structures and luminescence

Two metal-organic coordination polymers, [Zn(1,2,4-BTC)(bipy)] n (1) (1,2,4-BTC = 1,2,4-benzenetricarboxylic acid, bipy = 4,4′-bipyridine) and [Zn(1,3,5-BTC)(bipy)(H2O) · 3H2O] n (2) (1,3,5-BTC = 1,3,5-benzenetricarboxylic acid, bipy = 4,4′-bipyridine), have been synthesized using the principle of crystal engineering. Despite similar reactants and reaction conditions, complex 1 is an infinite 2-D square-grid network while complex 2 is a 1-D zigzag chain. 4,4′-bipyridine is a terminal monodentate ligand towards the Zn centers, which is rare in Zn polymers because 4,4′-bipyridine is a linear molecule and bridges central ions using two nitrogen atoms. Both coordination polymers show blue luminescence in the solid state at room temperature.

Hydrothermal synthesis, crystal structures and properties of new Fe II, Co II, Ni II, and Zn II complexes with 6-quinolinecarboxylate: Interplay of coordinative and noncovalent interactions

Reactions of Fe II, Co II, Ni II, and Zn II salts with 6-quinolinecarboxylic acid (H L) under the hydrothermal conditions afford three monomeric complexes [M( L) 2(H 2O) 4] (M = Fe II for 1, Co II for 2, and Ni II for 3) and a 1-D polymeric species {[Zn( L) 2(H 2O)] · H 2O} n ( 4). The crystal structures of the ligand H L and these four complexes have been determined by using the X-ray single-crystal diffraction technique. The results suggest that complexes 1– 3 are isostructural, displaying novel 3-D pillar-layered networks through multiple intermolecular hydrogen bonds, whereas in coordination polymer 4, the 1-D comb-like coordination chains are extended to generate a hydrogen-bonded layer, which is further reinforced via aromatic stacking interactions. Solid-state properties such as thermal stability and fluorescence emission of the polymeric Zn II complex 4 have also been investigated.

Enantioselective phenylacetylene addition to aldehydes and ketones catalyzed by recyclable polymeric Zn(salen) complex

New polymeric Zn(salen) complex was employed in the enantioselective phenylacetylene addition to aldehydes and ketones to produce corresponding chiral secondary propargylic alcohols with yields (up to 96%) and enantioselectivity (up to 72%) and tertiary propargylic alcohols with yields (up to 79%) and enantioselectivity (up to 68%) at room temperature, with added advantage of four times reuse with retention of enantioselectivity.

Recent Advances in Luminescent Monomeric, Multinuclear, and Polymeric Zn(II) and Cd(II) Coordination Complexes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Recent Advances in Luminescent Monomeric, Multinuclear, and Polymeric Zn(II) and Cd(II) Coordination Complexes

‘Luminescence research has a long history full of splendor and surprise, and a bright future, promising variegated applications to probe molecules and crystals, to visualize atomic phenomena, …’ H. J. Queisser, 1981 This article briefly summarizes recent progress on the luminescence studies of monomeric, multinuclear, and polymeric Zn(ii)/Cd(ii) coordination complexes, involving spectroscopic, photophysical, and photochemical studies, as well as molecular and electronic structural investigations, focussing mainly on the interplaying factors that govern the luminescent origin of the lowest-lying emissive states. Current results show that, for Zn(ii)/Cd(ii) coordination complexes in general, the nature of the metal centres and ligands and the rigid metal-oxy (or -hydroxy) clusters are factors governing their luminescent origin of the lowest-lying emissive states; different types of ligands and coordination structures may result in different emission mechanisms.

Synthesis and characterization of the zinc(II) complex of a bleomycin analogue: a unique polymeric 2-[((2-(4-imidazoyl)ethyl)amino)carbony]-6-[((2-amino-2-methylpropyl)amino)methyl]pyridine zinc(II) nitrate complex

The reaction of 2-[((2-(4-imidazoyl)ethyl)amino)carbonyl]-6-[((2-amino-2-methylpropyl)amino)methyl]pyridine (L) with Zn II(NO 3) 2·6H 2O has afforded a novel one-dimensional polymeric Zn II complex, (Zn II(L)(NO 3) 2) n ( 2). Complex 2 crystallizes in the space group P2 1/n with a=8.955(3), b=13.216(3), c=18.941(3) Å, β=103.39(2)°, V=2180.6(10) Å 3, and Z=4. The geometry of each Zn II is approximately a trigonal bipyramid: three nitrogens and one oxygen of the amide group are coordinated to the zinc while the fifth site is occupied by the imidazole nitrogen of a neighboring unit.

Zinc Complexes of S,N Ligands Derived from Thiazolines

Three different thiazoline derivatives or their tautomeric mercaptoethylamine derivatives were used for the preparation of zinc complexes containing S,N ligands. 2-(2-pyridyl)-3-(2-pyridylmethyl)-1,3-thiazolidine (PPMT) could not be opened reductively but acted as a tridentate nitrogen ligand in (PPMT)ZnX2 (1a, b, X = Br, NO3). The thiazolidine tautomer N-(2-mercaptoethyl)salicylideneimine (MESIH2) yielded polymeric (MESI)Zn (2) and, after oxidation, monomeric (MESI)2Zn (3) containing a disulfide unit. The 2-aryl-benzo-1,3-thiazoline tautomers N-(2-mercaptophenyl)-p-fluoroben-zylideneimine (MPFBH) and N-(2-mercaptophenyl)-p-meth-oxybenzylideneimine (MPMBH) underwent reaction with diethyl zinc resulting in the unstable L . Zn-Et complexes 4a and b, which are probably dimeric and the stable 2:1 complex (MPFB)2Zn (5). The structures of 3 and 5 were determined and were found to exhibit distorted tetrahedral ZnN2O2 and ZnN2S2 coordinations, respectively.