A cis-IrL(CO) Group Responds to Increasing Steric Bulk of L by M−L Stretching, Not M−C−O Tilting or Bending
摘要:
The crystal structures of [Ir(2-R-bq)(PPh3)(2)(H)(CO)](+) (bq = benzoquinolinato; R = H, i-Pr, t-Bu) show that steric interference caused by contact between the bulky pendant R groups of the bq and the C of the cis-CO is relieved by Ir-N bond stretching in the Irbq system and bending of the trans-Ph3P-Ir-PPh3 groups, rather than by tilting or bending of the CO. Ir-CO is therefore more rigid than the Ir-N and Ir-P bonds. The Ir-N stretching is aided by the presence of a high trans effect H trans to N.
2-取代的苯并喹啉Ir(III)配合物的固态结构和NMR数据表明,尽管在Ir中心附近有可用的配位位点,但侧基G不一定变得无规。因此,对于G = t -Bu,观察到了迷雾结构,但是对于G = i -Pr,潜在的迷幻i -Pr甲基指向远离金属的方向。ONIOM(B3PW91 / UFF)的计算重现了实验观察结果,并表明几种配体-配体相互作用(平行的芳族堆积和CH-··H-Ir相互作用)成功地以能量与竞争性竞争。发现氟苯(PhF)是用于合成t的更好的非配位极性溶剂-Bu配合物比二氯甲烷复杂。