...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >4-Methoxy- and 4-cyano-substituted lithium aryloxides: electronic effects of substituents on aggregation
【24h】

4-Methoxy- and 4-cyano-substituted lithium aryloxides: electronic effects of substituents on aggregation

机译：4-甲氧基和4-氰基取代的芳基锂氧化物：取代基对聚集的电子效应

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The para-substituted lithium aryloxides [{4-NC-C6H4OLi center dot(Pyr)(2)}(2)center dot Pyr] 1a, [{4-NC-C6H4OLi center dot(THF)(2)}(2)] 1b, [{4-MeO-C6H4OLi center dot Pyr}4] 2a, [4-MeO-C6H4OLi center dot(THF)(n)] 2b, [{4-NC-2,6-(t-Bu)(2)-C6H2OLi center dot( Pyr)(2)}(infinity)] 3a, [{4-NC-2,6-(t-Bu)(2)-C6H2OLi center dot(THF)(2)}(infinity)] 3b, [{4-MeO-2,6-(t-Bu)(2)-C6H2OLi center dot Pyr}(2)center dot(Pyr)(2)] 4a, and [4-MeO-2,6-(t-Bu)(2)-C6H2OLi center dot(THF)(n)] 4b were prepared by the direct deprotonation of the corresponding phenol with an alkyllithium base ( BuLi or MeLi) in the appropriate solvent, either pyridine or THF. All compounds were characterized by H-1 and C-13 NMR spectroscopy, and the crystal structures of 1a, 1b, 2a, 3a, 3b and 4a were elucidated. The cyano derivatives 1a and 1b adopt discrete tetrasolvated Li2O2 ring dimers whereas the methoxy analogue 2a crystallizes as a tetrasolvated molecular tetramer with a pseudo cubic Li4O4 core. The sterically encumbered cyano derivatives 3a and 3b form isostructural 1D polymeric chains of monomers via bridging of the phenolate ligands through Li center dot center dot center dot NC and Li - O contacts. In comparison, the crystal structure of the methoxy counterpart 4a is a disolvated molecular Li2O2 ring dimer. Solution NMR spectroscopic studies of 1 - 4 in d(5)-pyridine and d(8)-THF indicate that the methoxy complexes are more highly aggregated than the cyano derivatives, consistent with the solid-state studies. Ab initio molecular orbital calculations at the HF/6-31G* level of theory indicate that the origin of the aggregation state variations between the cyano and methoxy complexes is due to electronic effects.
机译：对位取代的芳基锂氧化物[{4-NC-C6H4OLi中心点（Pyr）（2）}（2）中心点Pyr] 1a，[{4-NC-C6H4OLi中心点（THF）（2）}（2） ] 1b，[{4-MeO-C6H4OLi中心点Pyr} 4] 2a，[4-MeO-C6H4OLi中心点（THF）（n）] 2b，[{4-NC-2,6-（t-Bu） （2）-C6H2OLi中心点（Pyr）（2）}（无穷大）] 3a，[{4-NC-2,6-（t-Bu）（2）-C6H2OLi中心点（THF）（2）}（无限）] 3b，[{4-MeO-2,6-（t-Bu）（2）-C6H2OLi中心点Pyr}（2）中心点（Pyr）（2）] 4a和[4-MeO-2通过在适当的溶剂（吡啶或吡啶）中将相应的苯酚与烷基锂碱（BuLi或MeLi）直接脱质子化反应，制得[6-（t-Bu）（2）-C6H2OLi中心点（THF）（n）] 4b。四氢呋喃。所有化合物均通过H-1和C-13 NMR光谱表征，并阐明了1a，1b，2a，3a，3b和4a的晶体结构。氰基衍生物1a和1b采用离散的四溶剂化Li2O2环二聚体，而甲氧基类似物2a结晶为具有伪立方Li4O4核的四溶剂化分子四聚体。位阻氰基衍生物3a和3b通过酚盐配体通过Li中心点中心点中心点NC和Li-O触点桥接，形成单体的同构一维聚合物链。相比之下，甲氧基对应物4a的晶体结构是脱溶剂的分子Li 2 O 2环二聚体。在d（5）-吡啶和d（8）-THF中1-4的溶液NMR光谱研究表明，与氰基衍生物相比，甲氧基络合物的聚集度更高，这与固态研究一致。从理论上讲，HF / 6-31G *水平的从头算分子轨道计算表明，氰基和甲氧基配合物之间的聚集态变化的起因是由于电子效应。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号