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Six metal–organic coordination polymers or metallomacrocycles, [Zn2Cl4(L2)2]·3H2O (1), [Zn2Br4(L2)2]·0.5H2O (2), {[Cu(L2)2(H2O)2](NO3)2·4H2O·4CH3OH}n(3), [Zn2Br4(L3)2] (4), (ZnBr2L4)n(5) and (ZnBr2L5)n(6), were prepared from zinc(ii) or copper(ii) salts with flexible bis(pyridylcarbamate) ligands L2to L5[L2= 3-pyridyl-carbamic-acid-oxydi-1,2-ethanediylester, L3= 3-pyridinyl-carbamic-acid-1,2-ethanediyl-bis(oxy-2,1-ethanediyl)ester, L4= 3-pyridinyl-carbamic-acid-1,3-propanediylester and L5= 3-pyridinyl-carbamic-acid-1,4-butanediylester]. Compounds 1, 2and 4are hydrogen-bonded 3D porous nanotubular structures composed of metallomacrocycles. Compound 3has a racemic framework formed by 2D homochiral layers. Compound 5is a 1D meso-helical chain and 6is a 1D linear chain, both of which are further connected by N–HO and C–HO hydrogen bonds and π–π interactions into 3D frameworks. The highly flexible bis(pyridylcarbamate) ligands show dramatically different conformations with various metal ions and counteranions, thus leading to the structural diversity of these complexes. [ABSTRACT FROM AUTHOR]

The reaction of CoCl2·6H2O or Co(NO3)2·6H2O with a semi-rigid ditopic ligand 2,6-bis(1-(2,6-diisopropyl-4-(pyridin-3-yl)phenylimino)ethyl)pyridine (L) in various solvent systems led to four complexes, {[CoCl2L2]·CH2Cl2}n(1a), {[Co(NO3)2L2]·CH2Cl2}n(1b), {[Co4(μ2-Cl)2(μ2-L)2Cl8]·xH2O}n(2), and [Co4(NO3)8L2(CH3CN)2]·xH2O (3). Compounds 1aand 1bare isostructural 1D looped-chain coordination polymers constructed by 44-membered [Co2L2] macrocyclic units. Compound 2shows an unprecedented double μ2-Cl bridged 1D chain structure containing 36-membered [Co4L2] macrocycles. Interestingly, the Co(ii) ions are partially oxidized to form the CoIII2Cl2bridges, and the [CoII2L2] metallocycles are linked by these CoIII2Cl2units to generate the 1D chain. Compound 3is a discrete 0D 36-membered metallomacrocycle comprised of four Co(ii) ions and two bridging ligands. The structural variation of the complexes is related to the conformational changes of the semirigid ligand L induced by different solvent systems. [ABSTRACT FROM AUTHOR]

Self-assembly of two flexible bis-pyridylurea ligands, pentane-1,5-diylbis(3-pyridin-3-ylurea) (L5) and hexane-1,6-diylbis(3-pyridin-3-ylurea) (L6) with ZnSO4or CdSO4(metal-to-ligand molar ratio 1 : 2) results in three metal–organic frameworks with (4,4) net structures, {[ML2(H2O)2]SO4·2H2O}n(1: Zn, L5; 2: Cd, L5; and 3: Zn, L6). Single-crystal X-ray diffraction analyses reveal that all the compounds are characteristic of a 3-fold parallel interpenetrated framework with cavities suitable for encapsulating the sulfate anion despite the different spacer lengths ((CH2)5and (CH2)6) of the two ligands and variation of the metal ions. The ligand adopts an anti–anticonformation and functions as a bridging bidentate linker, while the sulfate ion is selectively bound by four urea functionalities viamultiple hydrogen bonds. [ABSTRACT FROM AUTHOR]

Four unprecedented 1D → 1D interpenetrated (2,4) coordination polymers were obtained from a bis(4-pyridylurea) ligand and octahedral metal ions viacatenation of two parallel and collinear 1D ribbons of rings; the ligand L shows an ideal flexibility and adaptability in the formation of these structures. [ABSTRACT FROM AUTHOR]

Anion complexation of a flexible bis(pyridylcarbamate) receptor, 3-pyridinyl-carbamic-acid-1,2-ethanediylester (L), is reported. Upon addition of a series of inorganic acids (H3PO4, H2SO4, HClO4, HCl and HBr), the ligand L can be doubly protonated and bind the anions through hydrogen bonding interactions, affording the adducts 1–5. The binding modes of the protonated ligand ([LH2]2+) with anions in 1–5in the solid state are established by X-ray single crystal diffraction. Of particular interest is that the three oxoanion complexes (1–3) feature intriguing anionic polymer fashions, such as the novel double-stranded dihydrogen phosphate chain in 1, the infinite [-sulfate-(H2O)2-]nchain in 2, and hydrogen-bridged helical perchlorate chain in 3. For complexes 4and 5, the packing diagram displays a layered structure with the halide anions located between the adjacent cationic arrays. Receptor L can selectively crystallize with the sulfate anion from the acid mixture H3PO4, H2SO4, HClO4, HCl and HBr. [ABSTRACT FROM AUTHOR]