Structure of Three Related Diphosphorus Ligands: Highlighting the Significance of the Backbone
作者:Thashree Marimuthu、Muhammad D. Bala、Holger B. Friedrich
DOI:10.1007/s10870-011-0233-1
日期:2012.3
The three compounds contained in this report—4,6-bis(diphenylphosphino)-10,10-dimethylphenoxasilin (sixantphos), 1; 4,5-bis(diphenylphosphino)-9-isopropylidenexanthene, (isopropxantphos) 2 and bis-(2-diphenylphosphino)-p-tolyl) ether (PTEphos) 3, all contain a common ether-linked diphenylphosphino backbone. These structures are of interest with respect to the intra-molecular P···P distance which is 3.884(2), 4.104(2) and 5.151(2) Å for 1, 2 and 3 respectively. The differences in the P···P distances are as a result of the variations in the backbones. Structure 1 shows a significant roof-like bending of the backbone along the axis of planarity involving the oxygen and Si donor atoms. Compound 2 is also folded with a larger dihedral angle of 35.85(2)° as compared to 24.14(2)° found in 1. The backbone in structure 3 is significantly bent and twisted with a dihedral angle of 67.34(2)°. These data show the effect on the intra-molecular P···P distance of varying the backbone of three xantphos-type ligands, with respect to the nature of the heterocycle donor 1, the substituent on the donor 2 and total loss of xanthene character 3. Differences in the P···P distances of three xantphos-based compounds are related to the variations in the backbones. These intra-molecular P···P distances vary between 3.884(2) Å, 4.104(2) Å and 5.151(2) Å for the reported compounds.
本报告中包含的三种化合物——4,6-双(二苯基膦)-10,10-二甲基苯氧基硅烷(六抗磷)、1;4,5-双(二苯基膦)-9-异丙亚基氧杂蒽(异丙氧杂磷)2和双(2-二苯基膦)-对甲苯基)醚(PTE磷)3,均含有共同的醚键联二苯基膦骨架。这些结构与分子内P···P距离有关,1、2和3的分子内P···P距离分别为3.884(2)、4.104(2)和5.151(2) Å。P···P距离的差异是骨架变化的结果。结构1显示,骨架沿平面轴线发生明显的屋顶状弯曲,涉及氧和硅供体原子。化合物2也发生折叠,二面角为35.85(2)°,而结构1中的二面角为24.14(2)°。结构3中的骨架发生明显的弯曲和扭曲,二面角为67.34(2)°。这些数据表明,改变三种氧杂磷杂环型配体的骨架对分子内P···P距离的影响,涉及杂环供体1的性质、供体