[Co2（H2O）6（bpdc）2]·3.75H2O的原位合成、晶体结构及电化学性质研究

室温下,Co（NO3）2·6H2O与1,10–邻菲罗啉–5,6–二酮（pdon）的水溶液进行原位反应,得到一维链状配合物晶体{Co2（H2O）6（bpdc）2]·3.75H2O}n（bpdc=2,2＇–联吡啶–3,3＇–二羧酸）.单晶X–射线衍射分析表明：该晶体属于单斜晶系,P21/c空间群,晶胞参数为：a=18.001（4）A,b=11.336（2）,c=18.192（4）A,β=118.88（3）°,V=32501（2）A3,Dcalc=1.578 g·cm^-3.每个钴（Ⅱ）离子与周围2个氮原子和4个氧原子配位,形成扭曲的八面体构型,并通过bpdc连接形成沿b轴无限延伸的手性螺旋链.在整个晶体结构中,这些链以准一维堆积方式排列,相互之间存在广泛的氢键作用.同时,电化学分析表明：在磷酸盐缓冲溶液（pH=7.0）中,该配合物在-0.6～0.6V电压范围内具有电化学活性,电极反应为准可逆的Co（Ⅲ）与Co（Ⅱ）的氧化还原过程.

In-situ Synthesis, Structure and Characterization of [Co2(H2O)6(bpdc)2]'3.75H2O [bpdc=2,2'-bipyridyl-3,3'-dicarboxylate]

A new 1D chain coordination polymer Co2（H2O）6（bpdc）2]＇3.75H2O （bpdc=2,2＇bipyridyl-3,3＇-dicerboxylate） is in-situ synthesized resulting from the reaction of cobalt （II） nitrate with an equivalent of 1,10-phenanthroline-5,6-dione in aqueous solution. Single-crystal X-ray reveals that title complex crystallizes in the monoclinic space group P21/c with the unit cell dimensions a=18.001（4）A, b=11.336（2）A, c=18.192（4） A, β= 118.88（3）°, V=32 501（2） A3, Dcalc=l.578 g·cm^-3. Co（II） is hexa-coordinated in a distorted octahedral geometry by two N atoms from one 2,2＇-bipyridyl-3,3＇-dicarboxylate and four O atoms from one carboxylate and three water molecules. The complex assembles into 1D left- and right-handed helical chains. The water molecules reside between the chains. The electrochemical studies show that the Co（Ⅱ） complex exhibits a quasi-reversible one-electron process that the Co （Ⅱ） is oxidized to Co（Ⅲ） in phosphate solution.