Beaini Samar, Deacon Glen B, Erven Anja P, Junk Peter C, Turner David R
School of Chemistry, Monash University, P.O. Box 23, Clayton, Vic 3800, Australia.
Chem Asian J. 2007 Apr 2;2(4):539-50. doi: 10.1002/asia.200700005.
The dimeric complex [Li(Ph2pz)(OEt2)]2 (1) and tetrameric cluster [Na(Ph2pz)(thf)]4 (2) were prepared by treatment of alkali-metal reagents (nBuLi and Na{N(SiMe3)2}, respectively) with 3,5-diphenylpyrazole (Ph2pzH) in Et2O (1) or THF (2). The polymer [Na(tBu2pz)]n (3) was obtained from reaction at elevated temperature in a sealed tube between Na metal and 3,5-di-tert-butylpyrazole (tBu2pzH). The complex [Na4(tBu2pz)2(thf)3(obds)]2 (4; obds = (OSiMe2)2O) was obtained as a minor product from prolonged treatment of tBu2pzH with elemental sodium in a silicone-greased flask. All four alkali-metal pyrazolato complexes were characterized by IR and 1H NMR spectroscopy and X-ray crystallography.The Li dimer 1 displays mu-eta(2):eta(1) lithium-pyrazolato binding, in which both lithium atoms are four-coordinate. Room- and variable-temperature NMR studies (1H, 13C, and 7Li) of 1 suggest similar behavior in solution, with peaks coalescing at low temperatures. Complexes 2 and 4 display distorted cubane structures. In 2, all the sodium atoms are five-coordinate, whereas 4 contains two sodium/pyrazolate/thf clusters (4:2:3 ratio) bridged by two obds(2-) units, as well as two four-coordinate and two five-coordinate sodium atoms. Compound 3 is composed of two independent chains with the unusual coordination modes mu3-eta(5):eta(2):eta(2), mu3-eta(5):eta(2):eta(1), and mu3-eta(4):eta(2):eta(1), with five-, six-, and seven-coordinate sodium atoms. Two oxo-centered M8 cage complexes [(tBu2pz)6Li8O] (5) and [(tBu2pz)6Na8O] (6) were obtained as by-products from attempted preparation of [Li(tBu2pz)] and [Na(tBu2pz)], respectively, and their structures were determined.
通过分别用碱金属试剂（正丁基锂和Na{N(SiMe₃)₂}）与3,5 - 二苯基吡唑（Ph₂pzH）在乙醚（用于制备二聚体配合物[Li(Ph₂pz)(OEt₂)]₂ (1)）或四氢呋喃（用于制备四聚体簇合物[Na(Ph₂pz)(thf)]₄ (2)）中反应，制备了二聚体配合物[Li(Ph₂pz)(OEt₂)]₂ (1)和四聚体簇合物[Na(Ph₂pz)(thf)]₄ (2)。聚合物[Na(tBu₂pz)]ₙ (3)是通过金属钠与3,5 - 二叔丁基吡唑（tBu₂pzH）在密封管中于高温下反应得到的。配合物[Na₄(tBu₂pz)₂(thf)₃(obds)]₂ (4; obds = (OSiMe₂)₂O)是在涂有硅脂的烧瓶中用元素钠长时间处理tBu₂pzH时作为次要产物得到的。所有四种碱金属吡唑基配合物均通过红外光谱、¹H核磁共振光谱和X射线晶体学进行了表征。锂二聚体1显示出μ - η(2):η(1)锂 - 吡唑基配位，其中两个锂原子均为四配位。对1进行的室温及变温核磁共振研究（¹H、¹³C和⁷Li）表明其在溶液中的行为相似，峰在低温下合并。配合物2和4显示出扭曲的立方烷结构。在2中，所有钠原子均为五配位，而4包含两个由两个obds²⁻单元桥连的钠/吡唑酸盐/四氢呋喃簇（比例为4:2:3），以及两个四配位和两个五配位的钠原子。化合物3由两条独立的链组成，具有不寻常的配位模式μ₃ - η(5):η(2):η(2)、μ₃ - η(5):η(2):η(1)和μ₃ - η(4):η(2):η(1)，钠原子的配位数分别为五、六和七。两种以氧为中心的M₈笼状配合物[(tBu₂pz)₆Li₈O] (5)和[(tBu₂pz)₆Na₈O] (6)分别作为试图制备[Li(tBu₂pz)]和[Na(tBu₂pz)]的副产物得到，并确定了它们各自的结构。
