...
  • 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 >Conformational analysis of PEt_3 and P(OMe)_3 in metal complexes
【24h】

Conformational analysis of PEt_3 and P(OMe)_3 in metal complexes

机译：金属络合物中PEt_3和P（OMe）_3的构象分析

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 conformations of the archetypal acyclic phosphorus ligands PEt_ 3 and P(OMe)_3 are classified on the basis of the observation that torsions about the P-C (or P-O) bonds show favoured conformations lying close to gauche (±60°) or anti values (180°). Analysis of the symmetry of the conformation space defined by the three M-P-X-C (X = CH_2 or O) torsion angles (t_(1-3)) implies the existence of seven unique conformer types (A (aaa), B (g~+g~ +g~+), C (ag~+g~+), D (aag~ +), E (g~-ag~+), F (ag~-g~+), G (g~-g~+g~+) and their symmetry equivalents) arising from the combinations of g~-, g~+ and a torsions. These conformers are observed in 1972 M-PEt_3 and 735 M-P(OMe)_ 3 fragments from crystal structures of metal complexes in the CSD following the popularity sequence: F > C?D > B > G > E?A for M-PEt_3; and: C > D > F?E?A, B, G. for M-P(OMe)_ 3. Pathways for low-energy interconversion of these conformers, dominated by single chain flip routes, are readily inferred for M-P(OMe)_ 3. The conformers of M-PEt_3 are apparently less readily interconverted. The popularity of conformations is only loosely related to the energies of these conformations as calculated by DFT or MM methods for two-, four- (square planar) and six-coordinate metal complexes of these ligands (and free PEt_3 and P(OMe)_3). It would appear that the conformational preferences observed are determined by a balance between intra-ligand effects (repulsion between chains and avoidance of syn-pentane-like); inter-ligand effects (repulsions between gauche substituents at P and cis co-ligands notably when the coordination number at the metal is high); and residual anomeric effects (weakly favouring anti conformations in P(OMe)_3 species).
机译：原型无环磷配体PEt_3和P（OMe）_3的构象是根据以下观察结果进行分类的：关于PC（或PO）键的扭转显示出接近gauche（±60°）或反值的有利构象（ 180°）。分析三个MPXC（X = CH_2或O）扭转角（t_（1-3））定义的构象空间的对称性意味着存在七个独特的构象异构体类型（A（aaa），B（g〜+ g 〜+ g〜+），C（ag〜+ g〜+），D（aag〜+），E（g〜-ag〜+），F（ag〜-g〜+），G（g〜-g由g〜-，g〜+和扭转的组合产生的（〜+ g〜+）及其对称等价物。这些构象在CSD中金属配合物的晶体结构的1972 M-PEt_3和735 M-P（OMe）_ 3片段中，按照以下流行度顺序观察：对于M-PEt_3，F> C？D> B> G> E？A;对于MP（OMe）_，C> D> F？E？A，B，G。3.容易推断出MP（OMe）_的低构象构象的低能互变途径，主要由单链翻转途径决定。 3. M-PEt_3的构象异构体显然不易相互转化。通过DFT或MM方法计算的这些配体的二，四（正方形平面）和六配位金属络合物（以及游离PEt_3和P（OMe）_3）的构象能量仅与这些构象的能量松散相关）。似乎观察到的构象偏好是由配体内效应（链间排斥和避免类似正戊烷）之间的平衡决定的。配体间效应（当金属上的配位数高时，P和顺式共配体上的gauche取代基之间的排斥力尤其明显）;和残留的异头作用（在P（OMe）_3种中弱支持反构象）。

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