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Two novel CuII coordination polymers, [Cu4O(L¹)4(N3)2]n(ClO4)4n·3nH2O (1) and [Cu7(L²)2(N3)14]n (2), have been synthesized from two zwitterionic carboxylate ligands, 1-carboxylatomethyl-4,4'-bipyridinium (L1) and 1-carboxylatomethyl-4,4'-dimethylenedipyridinium (L2). Compound 1 exhibits interpenetrated 3D diamond networks in which the unusual µ4-O-centred tetrahedral Cu4 clusters with peripheral 1,1-N3 and COO bridges are cross-linked by 4,4'-dipyridinium-1-methylene spacers. In compound 2, pentanuclear and dinuclear units with double azide bridges are linked into a unique 2D layer by μ3-1,1,3-N3, (1,1-N3)- (COO) and the organic backbone of the zwitterionic ligand. Magnetic studies reveal that compound 1 exhibits ferromagnetic coupling through (µ4-O)(1,1-N3) and antiferromagnetic coupling through the µ4-O-only and (µ4-O)(COO)2 pathways. Compound 2 exhibits ferromagnetic coupling within the (1,1-N3)2 bridged polynuclear units and weak antiferromagnetic coupling through μ3-1,1,3-N3, and (1,1-N3)(COO) between the units. [ABSTRACT FROM AUTHOR]

Three new Zn(ii) metal–organic coordination polymers, [Zn3(STDC)3(py)2] (1), [Zn3(STDC)3(4,4′-bpy)] (2), [Zn3(STDC)3(bpea)] · 3H2O (3), where H2STDC = trans-stilbene-4,4′-dicarboxylic acid, py = pyridine, 4,4′-bipy = 4,4′-bipyridine, bpea = 1,2-bis(4-pyridyl)ethane, were prepared by solvothermal reactions of Zn(ii) acetate with H2STDC in the presence of py or linear bis(pyridyl) molecules. Compound 1is a 2D triangle-tessellated layered network based on a pinwheel trinuclear zinc-carboxylate clusters as secondary building unit with py as the terminal ligand. Compounds 2and 3contain similar layers, which are linked into layer-pillared 3D frameworks by the ditopic bipy or bpea ligand in place of py. Comparing the structures of 2and 3, the increase in pillar length does not lead to increased multiplicity in interpenetration, due to the limitation of the intralayer space dimensions, but it induces expanded and unequal interlayer separations. [ABSTRACT FROM AUTHOR]

Solvothermal reactions of Zn(II), Cd(II), Mn(II), Co(II), or Ni(II) salts and 2-pyrimidinecarbonitrile (pymCN) in the presence of NaN3in DMF yielded seven metal−organic coordination polymers formulated as [Zn(pymtz)2]n(1), [NaMII(pymtz)3]n·G (M = Zn 2, Cd 3, Mn 4, Co for 5, and Ni for 6; G = DMF and/or H2O) and [Cd(pymtz)2]n(7) [pymtz = 5-(2′-pyrimidyl)tetrazolato]. Compounds 2−6are isomorphous and all contain neutral honeycomb layers in which pymtz serves as a bis(chelating) bridge between M(II) (M = Zn for 2, Cd for 3, Mn for 4, Co for 5, and Ni for 6) and Na, and the ellipse stacking of the layers generates one-dimensional hexagonal channels. Compounds 1and 7exhibit different (4,4) square grid networks. In 1, the Zn ions are octahedrally coordinated and linked by pymtz ligands in the μ2tridentate bridging mode, while in 7, the Cd(II) ions are eight-coordinated with a square prismatic geometry and bridged by bis(chelating) pymtz ligands. Compounds 2and 3can transform into 1and 7, respectively, by immersing the sample in appropriate solvents. Interestingly, photoluminescence measurements on Zn(II) and Cd(II) compounds show that the emission bands can be correlated to the coordination modes of the pymtz ligands. [ABSTRACT FROM AUTHOR]

Using trans-stilbene-4,4′-dicarboxylic acid (H2STDC) as bridging ligand, we have prepared four new coordination polymers with different transition metal ions, [Cu(STDC)(H2O)(py)2]·2py (1), [Cd(STDC)(py)2]·0.5py (2), [Co(STDC)(py)2]·0.5py (3), and [Ni2(STDC)2(py)4(H2O)]·py·0.5H2O (4), by hydrothermal reactions in the presence of pyridine (py). In compound 1, single metal ions are linked into quasi-linear coordination chains by the organic ligand, and the chains are further assembled into 3D supermolecular architectures through strong O−H (coordinate water)···O (carboxylate) and weak C−H (py)···π (benzene) hydrogen bonds. In compounds 2and 3, which are isomorphous, binuclear motifs with double carboxylate bridges are linked into two-dimensional (4,4) coordination layers exhibiting 2-fold inclined interpenetration. The last compound exhibits an abnormal 5-fold interpenetration of diamond networks, in which the tetrahedral building unit is defined by a binuclear motif with triple (two carboxylates and a water) bridges. Although it is impossible to rationalize the formation of these distinct structures, the differences can be related to the different disposition of the coordinated py (and water in 1)molecules around metal ions. All these coordination polymers contain voids occupied by guest molecules. The stability and guest inclusion properties of 2, 3, and 4have been investigated. While 3and 4undergo permanent framework collapse upon evacuation by heating, 2exhibits reversible framework transformation upon evacuation/absorption of the guest molecules. [ABSTRACT FROM AUTHOR]

A series of transition metal coordination polymers with azide and flexible zwitterionic dicarboxylate ligands was synthesized and structurally and magnetically characterized. These compounds are formulated as [M2(L¹)(N3)4] (L¹ = 4,4'-trimethylenedipyridinio-N,N'-diacetate and M = Mn, 1; Co, 2; and Ni, 3) and [ML²(N3)6(H2O)2] (L² = 4,4'-dipyridinio-N,N'-diacetate and M = Mn, 4; Co, 5). The isomorphous compounds 1-3 consist of two-dimensional coordination layers in which the anionic chains with mixed triple bridges (two end-on (EO) azides and a syn-syn carboxylate) are cross-linked by the flexible cationin 4,4'-trimethylenedipyridinium spacers, while the isomorphous compounds 4 and 5 consist of alternating chains with triple (two EO azides plus a carboxylate) and double (two end-to-end azides) bridges, the 4,4'-dipyridinium spacers serving as side bridges along the chain. Magnetic studies demonstrated that the triple bridge transmits antiferromagnetic coupling in the Mn(II) compounds (1 and 4) but ferromagnetic coupling in the Co(II) and Ni(II) species (2, 3, and 5). The differences have been discussed in terms of the collaboration or competition between the carboxylate and azide pathways. Compound 4 exhibits alternating antiferromagnetic interactions, while alternating ferromagnetic-ferromagnetic-antiferromagnetic interactions with spin canting are suggested for 5. [ABSTRACT FROM AUTHOR]

Manganese-based layered coordination polymer ([Mn-(tfbdc)(4,4'-bpy)(H20)2], Mn--LCP) with microporous structure was synthesized by reaction of 2,3,5,6-tetrafluoroterephthalatic acid(H2tfbdc) and 4,4'-bipyridine(4,4'-bpy) with manganese(ll) acetate tetrahydrate in water solution. Mn--LCP was characterized by elemental analysis, IR spectra, thermogravimetric analysis, X-ray single-crystal structure analysis, and powder X-ray diffraction. Magnetic susceptibility data from 300 to 1.8K show that there is a weak antiferromagnetic exchange between Mn(n) ions in Mn--LCP. As anode material, the Mn--LCP electrode exhibits an irreversible high capacity in the first discharge process and a reversible lithium storage capacity of up to about 390 mA h/g from the fourth cycle. It might provide a new method for finding new electrode materials in lithium-ion batteries [ABSTRACT FROM AUTHOR]