Build And Structure Characterization Pyrazinecarboxylate Metal Coordination Polymers

Twenty-four coordination polymers based on pyrazine carboxylic acid have been synthesized, which employ a variety of coordination modes with the metal atoms.[1] Six novel coordination polymers based on Pyrazine2,3-dicarboxylic acid (H2Pzdc),[Cd(pzdc)(H2O)]nΛ(H2O)n (1),[Pb3(pzdc)3(H2O)]n (2),[Cuo.5(Hpzdc)]n (3),[Ba(pzdc)(H2O)]n (4),[Ba(pzdc)]n (5),[Co(pzdc)2-2H2O]n (6) have been synthesized and characterized by single crystal X-ray diffraction analysis. One OD compound,[Cu(mpca)Br·H2O]n (7), have been prepared using5-methylpyrazine-2-carboxylic acid (Hmpca). Interestingly, compounds1and3generate2D (4,4) coordination layer; Compound2shows an extended3D framework with a previously unknown3D (3,4,5)-connected topology; In the compounds4and5, the ligand employs two unusual coordination modes, μ6-(η-N.O),(η2-O,O),(η2-O,O),(η2-O,O),O’,O" and μ6-(η2-N,O),(η2-O,O),O’,O", O" O"" respectively.[2] We employed the H2pzdc as ligand to construct15heterometallic framework,{[Ce2Co(pzdc)4(H2O)6]-2H2O}n (8),[Ag(pzdc)Sr(NO3)(H2O)]n (9),[Ag2(pzdc)2Ca(H2O)]n (10),[Mg(H2O)6][Cu(pzdc)2]-4H2O (13),[Ca2Cu(pzdc)2(NO3)2(H2O)8]n-2nH2O (14),[Sr2Cu(pzdc)2(Cl)2(H2O)10]n (15),[Sr2Cu(pzdc)2(NO3)2(H2O)8]n·2nH2O (16),[Ba2Cu(Cl)2(pzdc)2(H2O)]nH2O (17),[Mg(H2O)6]2n[Co(Hpzdc)3]2n (18),[Ca2Co(pzdc)2(Cl)2(H2O)10]n (19),[Sr2Co(pzdc)2(Cl)2(H2O)10]n (20),[Ba2Co(pzdc)2(Cl)2(H2O)10]n (21),[Ca2Ni(pzdc)2(Cl)2(H2O)10]n (22),[Sr2Ni(pzdc)2(Cl)2(H2O)10]n (23),[Ba2Ni(pzdc)2(Cl)2(H2O)i0]n (24). Compound8shows a three-dimensional herringbone structure? The3D topology of compound10is much like many overlays of coppers; From14to17and from19to24,[M2(pzdc)2](M=Cu, Mn, Co) acts as the secondary building units connected by the other secondary building units of [MnOm](M=Ca, Sr, Ba; n=2,3; m=2,3,4) to form a series of network structures from1D to3D;[Mg(H2O)6][Cu(pzdc)2]-4H2O(13) and [Mg (H2O)6]2n[Co(pzdc)3]2n(18) show the formation of the typical unit of [M(H2O)6] and the direction of the hydrogen bonds along with the hydrogen atoms of the coordinated water molecules.[3] Two Cu-K heterometallic compounds,[KCu(I3)(mpca)2(H2O)2]n (11) and [KCu(I3)(mpca)2(H2O)]n (12), have been prepared using Hmpca according to the different proportion of ligand. Single crystal X-ray diffraction reveals that both compounds exhibit (4,4)-connected networks, which are doubly interpenetrated by5-connected notes to generate the final3D framework with rectangular channels occupied by triiodide ions. I3-ion employs two kinds of coordination mode:μ1η1,μ2-η1,η1-Remarkably, reversible structural transformations occurred via dissolution/reorganization processes in water in two compounds.