Syntheses and Crystal Structures of Two New Ag(Ⅰ) Complexes with Betaine Derivative: Structure Changes via Metal-to-ligand Ratio

Two new Ag（I） complexes {Ag2（L）（NO3）（H2O）}n（1） and {Ag（L）}n·nH2O（2） have been synthesized via the reaction of silver nitrate and betaine derivative 1-carboxymethylpyridinium-3-carboxylate（L） by only changing the metal-to-ligand ratio. The results of X-ray crystallographic analysis indicate that complexes 1 and 2 both crystallize in the monoclinic space group P21/c with a = 5.0809（14）, b = 17.390（5）, c = 13.399（4）, β = 91.677（5）o, V = 1183.4（6）3, Z = 4, Mr = 475.90, Dc = 2.671 g/cm3, F（000） = 912, μ = 3.352 mm-1, S = 1.259, the final R = 0.0320 and wR = 0.0831 for 2036 observed reflections with I 〉 2σ（I） for 1 and a = 12.180（2）, b = 5.0283（10）, c = 14.396（3）, β = 94.87（3）o, V = 878.5（3）3, Z = 4, Mr = 306.02, Dc = 2.314 g/cm3, F（000） = 600, μ = 2.294 mm-1, S = 1.053, the final R = 0.0283 and wR = 0.0684 for 2011 observed reflections with I 〉 2σ（I） for 2. Complexes 1 and 2 both feature a unique 2D structure. For 1, the 2D undulated network consists of 1D infinite helical chains running parallel to the b axis, while for 2, the 2D network is made up of 1D tubes along the b axis. Moreover, the Ag…Ag interactions in complexes 1 and 2 are also discussed.

Synthesis and Structural Characterization of a New Hydrogen-bonded Polyrotaxane of [Co(H_2O)_6]_(2+) with 1,1′-(Propane-1,3-diyl)dipyridinium-4-carboxylate

A new double betaine 1,1′-（propane-1,3-diyl）dipyridinium-4-carboxylate L has been synthesized. Reaction of 1, 1′-（propane-1,3-diyl）dipyridinium-4-carboxylate tetrahydrate 1 with Co（ClO4）2-6H2O leads to the formation of a new Co（Ⅱ） coordination compound, namely [Co（H2O）6]-2H2O-2L-2ClO4 2. The crystal structures of 1 and 2 have been determined by single-crystal X-ray diffraction method. Crystal data for 1. monoclinic, space group C2/c, a = 18.945（4）, b = 7.700（2）, c = l 1.888（2）A,β = 101.67（3）°, V = 1698.3（6） A^3, Z = 4, F（000） = 760.0, Dc = 1.402 g/cm^3, the final R = 0.0607 and wR = 0.1607 for 950 observed reflections （1 〉 2σ（I））; and those for 2： monoclinic, space group P21/c, a = 17.982（1）, b = 15.879 （1）, c = 7.0716（5）/A,β= 100.675（1）°, V= 1984.3（3） ,A^3 Z= 4, F（000） = 1010.0, Dc = 1.631 g/cm^3, the final R = 0.0316 and wR = 0.0896 for 3784 observed reflections （1 〉20（I））. Crystal structure analysis indicates that in 1, molecules of L in a ＂V-shaped＂ conformation are linked to chains sustained by O-H…O hydrogen bonds between carboxylate groups and solvent water molecules. The chains are joined by O-H…O and C-H…O hydrogen bonds to further expand into a three-dimensional structure. For 2, molecules of L in a ＂Z-shaped＂ conformation are linked by hydrogen bonds between carboxylate groups and aqua ligands to form a chain of loops running down the b axis. The （2D→2D） polythreading in compound 2 represents the mode of parallel interpenetration of 2D sheets, having polyrotaxane character.