Coordination polymers and metallomacrocycles based on bis(pyridylcarbamate) ligands with flexible glycol spacers

Six metal-organic coordination polymers or metallomacrocycles, [Zn2Cl4(L2)(2)]center dot 3H(2)O (1), [Zn2Br4(L-2)(2)]center dot 0.5H(2)O (2), {[Cu(L-2)(2)(H2O)(2)](NO3)(2)center dot 4H(2)O center dot 4CH(3)OH}(n) (3), [Zn2Br4(L-3)(2)] (4), (ZnBr2L4)(n) (5) and (ZnBr2L5)(n) (6), were prepared from zinc(II) or copper(II) salts with flexible bis-(pyridylcarbamate) ligands L-2 to L-5 [L-2 = 3-pyridyl-carbamic-acid-oxydi-1,2-ethanediylester, L-3 = 3-pyridinyl-carbamic-acid-1,2-ethanediyl-bis(oxy-2,1-ethanediyl)ester, L-4 = 3-pyridinyl-carbamic-acid1,3-propanediylester and L-5 = 3-pyridinyl-carbamic-acid-1,4-butanediylester]. Compounds 1, 2 and 4 are hydrogen-bonded 3D porous nanotubular structures composed of metallomacrocycles. Compound 3 has a racemic framework formed by 2D homochiral layers. Compound 5 is a 1D meso-helical chain and 6 is a 1D linear chain, both of which are further connected by N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds and pi-pi 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.