一个新的Co(Ⅱ)、Co(Ⅲ)二维超分子配合物的合成及结构研究

Abstract

以过渡金属CO(Ⅱ)盐为原料,采用二(2-吡啶甲酰)胺、4-羟基-2,6-吡啶二甲酸和单臂氮氧自由基IM2Py(IM2Py=2-(2-吡啶基)-4,4,5,5-四甲基咪唑啉-1-氧基自由基)为配体合成配合物,由于自由基和CO(Ⅱ)之间的氧化还原反应,最终得到了CO(Ⅱ)、CO(Ⅲ)同时存在的金属配合物[CO(Ⅱ)(IMH2Py)2(H2O)2][CO(Ⅲ)(CdA)(bPCA)]2□21H2O,(IMH2Py=2-(2′-吡啶基)-4,4,5,5-四甲基-1-氧化-咪唑啉配体,CdA3-=4-羟基-2,6-吡啶二甲酸根,HbPCA=二(2-吡啶甲酰)胺),其中自由基被还原成IMH2Py。单晶X-射线衍射结果表明,配合物属三斜晶系,Pī空间群;晶胞参数A=0.839 6(9)nM,b=1.360 0(16)nM,C=1.846(2)nM,α=82.364(19)°,β=77.14(2)°,γ=77.00(2)°。分子结构单元由3个单核CO单元构成,包括2种配位方式的CO离子,中心位置的CO1处于六配位八面体构型COn2O4中是CO(Ⅱ)离子,与2个自由基还原产物IMH2Py和2个水分子配位;而处于两端相的CO2/CO2A相对于CO1中心对称是CO(Ⅲ)离子,处于六配位八面体构型COn4O2中,分别与一个4-羟基-2,6-吡啶二甲酸和二(2-吡啶甲酰)胺配位。分子结构单元最终通过氢键以及配体间的π…π相互作用,连接成为一个二维超分子结构。

In this study a new 2Dsupramolecular complex [Co(Ⅱ)(IMH2Py)2(H2O)2][Co(Ⅲ)(cda)(bpca)]2□21H2O(1)(cda =4-hydroxo-2,6-dicarboxylatopyridine,bpca= bis(2-pyridylcarbonyl) amine,IMH2Py=l-hydroxy-2(2'-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-lH-imidazole) containing both Co(Ⅱ) and Co(Ⅲ) has been synthesized and structurally characterized by Xray diffraction method.It crystallizes in the triclinic space group Pī,a =0.839 6(9) nm,b=1.360 0(16) nm,c=1.846(2) nm,α=82.364(19) °,β =77.14(2) °,γ=77.00(2) °.The molecule consists of three mononuclear cobalt units with two kinds of coordination environment.The center Co1is Co(Ⅱ) located in a distorted octahedral environment CoN2O4formed by two IMH2Py and two water molecules,while the terminals Co2/Co2Aare Co(Ⅲ) located in a distorted octahedral environment CoN4O2formed by a cda and bpca ligands.The three cobalt units are connected by hydrogen bonding andπ … πinteractions to form a 2Dsupramolecular structure.