A new type of monoanionic “scorpionate” ligand. Synthesis, spectroscopic characterisation and dynamic behaviour of some niobium(III) complexes
作者:Antonío Otero、Juan Fernández-Baeza、Juan Tejeda、Antonío Antiñolo、Fernando Carrillo-Hermosilla、Enrique Díez-Barra、Agustin Lara-Sánchez、María Fernández-López
DOI:10.1039/b002742l
日期:——
The syntheses of novel scorpionate ligands in the form of the lithium derivative [Li(H2O)(bdmpza)}4] 1 [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] or as the alcohol derivative 2,2-bis(3,5-dimethylpyrazol-1-yl)ethanol 2 (Hbdmpze) have been studied. These compounds are excellent precursors for the introduction of these scorpionate ligands into transition metal complexes. The complex [NbCl3(dme)}n] (dme = 1,2-dimethoxyethane) reacted with 1 and 2, the latter with prior addition of BunLi, to give the binuclear complexes [NbCl2(bdmpzx)}2] (x = a, 3; x = e, 4) [bdmpze = 2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide]. Complex 3 reacted with 1 to give the complex [NbCl(bdmpza)2}2] 5. In the same way the reaction of the mononuclear species [NbCl3(dme)(RCCRâ²)] with 1 and 2, the latter with prior addition of BunLi, gave the appropriate [NbCl2(bdmpzx)(RCCRâ²)] complexes [x = a, R = Râ²Â = Me, 6; Et, 7; Ph, 8; or SiMe3, 9; R = Ph, Râ²Â = Me, 10; R = Ph, Râ²Â = Et, 11; R = Ph, Râ²Â = SiMe3, 12; x = e, R = Râ²Â = Me, 13; Et, 14; or Ph, 15; R = Ph, Râ²Â = Me, 16; R = Ph, Râ²Â = Et, 17; R = Ph, Râ²Â = SiMe3, 18]. The structures of these complexes have been determined by spectroscopic methods. Variable-temperature NMR studies were carried out in order to study their dynamic behaviour in solution. The barriers to alkyne rotation have also been calculated. Reaction of 10 with LiCpâ² (Cpâ²Â = C5H4SiMe3) gave the mixed Cpâbdmpza complex [NbCpâ²Cl(bdmpza)] 19.
研究人员合成了锂衍生物 [Li(H2O)(bdmpza)}4] 1 [bdmpza =双(3,5-二甲基吡唑-1-基)乙酸酯] 或醇衍生物 2,2-双(3,5-二甲基吡唑-1-基)乙醇 2 (Hbdmpze) 形式的新型蝎酸盐配体。这些化合物是将这些蝎酸配体引入过渡金属配合物的极佳前体。络合物 [NbCl3(dme)}n] (dme = 1,2-二甲氧基乙烷)与 1 和 2(后者事先加入了 BunLi)反应,得到双核络合物 [NbCl2(bdmpzx)}2] (x = a, 3; x = e, 4)[bdmpze = 2,2-双(3,5-二甲基吡唑-1-基)乙醇]。络合物 3 与 1 反应生成络合物 [NbCl(bdmpza)2}2] 5。同样,单核物质[NbCl3(dme)(RCCRâ²)]与 1 和 2(后者事先加入了 BunLi)反应,得到了相应的[NbCl2(bdmpzx)(RCCRâ²)]络合物[x = a,R = Râ²Â = Me,6;Et,7;Ph,8;或 SiMe3,9;R = Ph,Râ²Â = Me,10;R = Ph,Râ²Â = Et,11;R = Ph,Râ²Â = SiMe3,12;x = e,R = Râ²Â = Me,13;Et,14;或 Ph,15;R = Ph,Râ²Â = Me,16;R = Ph,Râ²Â = Et,17;R = Ph,Râ²Â = SiMe3,18]。这些复合物的结构已通过光谱方法确定。为了研究它们在溶液中的动态行为,还进行了变温核磁共振研究。还计算了炔旋转的障碍。10 与 LiCpâ²(Cpâ² = C5H4SiMe3)反应生成了混合 Cpâbdmpza 复合物 [NbCpâ²Cl(bdmpza)] 19。