Wang Feng-Qin, Mu Wei-Hua, Zheng Xiang-Jun, Li Li-Cun, Fang De-Cai, Jin Lin-Pei
Department of Chemistry, Beijing Normal University, Beijing 100875, P.R. China.
Inorg Chem. 2008 Jun 16;47(12):5225-33. doi: 10.1021/ic8001916. Epub 2008 May 20.
Four copper(II) complexes [Cu3(PZHD)2(2,2'-bpy)2(H2O)2].3H2O (1), [Cu3(DHPZA)2(2,2'-bpy)2] (2), [Cu(C2O4)phen(H2O)].H2O (3), and [Cu3(PZTC)2(2,2'-bpy)2].2H2O (4) were synthesized by hydrothermal reactions, in which the complexes 1-3 were obtained by the in situ Cu(II)/H3PZTC reactions (PZHD3- = 2-hydroxypyrazine-3,5-dicarboxylate, 2,2'-bpy = 2,2'-bipyridine, DHPZA3- = 2,3-dihydroxypyrazine-5-carboxylate, C2O42- = oxalate, phen = 1,10-phenanthroline, and H3PZTC = pyrazine-2,3,5-tricarboxylic acid). The Cu(II)/H3PZTC hydrothermal reaction with 2,2'-bpy, without addition of NaOH, results in the formation of complex 4. The complexes 1-4 and transformations from H3PZTC to PZHD3-, DHPZA3-, and C2O4(2-) were characterized by single-crystal X-ray diffraction and theoretical calculations. In the complexes 1, 2, and 4, the ligands PZHD3-, DPHZA3-, and PZTC3- all show pentadentate coordination to Cu(II) ion forming three different trinuclear units. The trinuclear units in 1 are assembled by hydrogen-bonding and pi-pi stacking to form a 3D supramolecular network. The trinuclear units in 2 acting as building blocks are connected by the carboxylate oxygen atoms forming a 2D metal-organic framework (MOF) with (4,4) topology. While the trinuclear units in 4 are linked together by the carboxylate oxygen atoms to form a novel 2D MOF containing right- and left-handed helical chains. The theoretical characterization testifies that electron transfer between OH- and Cu2+ and redox of Cu 2+ and Cu+ are the most important processes involved in the in situ copper Cu(II)/H3PZTC reactions, forming complexes of 1-3.
通过水热反应合成了四种铜（II）配合物[Cu3(PZHD)2(2,2'-bpy)2(H2O)2].3H2O（1）、[Cu3(DHPZA)2(2,2'-bpy)2]（2）、[Cu(C2O4)phen(H2O)].H2O（3）和[Cu3(PZTC)2(2,2'-bpy)2].2H2O（4），其中配合物1 - 3是通过原位Cu（II）/H3PZTC反应得到的（PZHD3- = 2 - 羟基吡嗪 - 3,5 - 二羧酸盐，2,2'-bpy = 2,2'-联吡啶，DHPZA3- = 2,3 - 二羟基吡嗪 - 5 - 羧酸盐，C2O42- = 草酸盐，phen = 1,10 - 菲咯啉，H3PZTC = 吡嗪 - 2,3,5 - 三羧酸）。在不添加NaOH的情况下，Cu（II）/H3PZTC与2,2'-bpy进行水热反应，生成配合物4。通过单晶X射线衍射和理论计算对配合物1 - 4以及H3PZTC向PZHD3-、DHPZA3-和C2O4(2-)的转化进行了表征。在配合物1、2和4中，配体PZHD3-、DPHZA3-和PZTC3-均与Cu（II）离子呈现五齿配位，形成三种不同的三核单元。1中的三核单元通过氢键和π - π堆积组装形成三维超分子网络。2中的三核单元作为结构单元，通过羧酸根氧原子相连，形成具有（4,4）拓扑结构的二维金属有机框架（MOF）。而4中的三核单元通过羧酸根氧原子连接在一起，形成一种包含右手和左手螺旋链的新型二维MOF。理论表征证明，OH-与Cu2+之间的电子转移以及Cu 2+和Cu+的氧化还原是原位铜Cu（II）/H3PZTC反应中形成配合物1 - 3所涉及的最重要过程。
