用户名: 密码: 验证码:
Rhodium and Iridium Complexes with a New Scorpionate Phosphane Ligand
详细信息    查看全文
文摘
A straightforward synthesis of a new hybrid scorpionate ligand [(allyl)2B(CH2PPh2)(Pz)]鈭?/sup> ([A2BPN]鈭?/sup>) is reported. Coordination to rhodium resulted in square-planar complexes [Rh(魏2-A2BPN)(L)(L鈥?] [L = L鈥?= 1/2cod (1,5-cyclooctadiene), CNtBu, CO (6); L = CO, L鈥?= NH3, pyridine, PPh3, PMe3] for which spectroscopic data and the molecular structure of [Rh(魏2-A2BPN)(CO)PPh3] (11) indicate the ligand to be 魏N,魏P-bound to rhodium with two dangling free allyl groups. Studies in solution point out that the six-membered Rh鈥揘鈥揘鈥揃鈥揅鈥?img src="/templates/jsp/_style2/_achs/images/tiebar-above-end.gif" class="tbAbove" alt="tiebar above end"/>P metallacycle undergoes a fast inversion in all of them. The bis(carbonyl) complex 6 easily loses a CO group to give [{Rh(A2BPN)(CO)}2], a dinuclear compound in which two mononuclear subunits are brought together by two bridging allyl groups. Coordination to iridium is dominated by a tripodal 魏N,魏P,畏2-C鈺怌 binding mode in the TBPY-5 complexes [Ir(魏3-A2BPN)(L)(L鈥?] [L = L鈥?= 1/2cod (3), CNtBu (5), CO (7); L = CO, L鈥?= PPh3 (13), PMe3 (14), H2C鈺怌H2, (17), MeO2CC鈮CO2Me (dmad, 18)], as confirmed by the single-crystal structure determination of complexes 3 and 18. A fast exchange between the two allyl arms is observed for complexes having L = L鈥?(3, 5, and 7), while those having CO and L ligands (14, 17, and 18) were found to be nonfluxional species. An exception is complex 13, which establishes an equilibrium with the SP-4 configuration. Protonation reactions on complexes 13 and 14 with HCl yielded the hydride complex [Ir(魏2-A2BPN)(CO)(Cl)(H)PPh3] (15) and the C-alkyl compound [Ir{魏3-(allyl)B(CH2CHCH3)(CH2PPh2)(Pz)}(Cl)(CO)PMe3] (16), respectively. The bis(isocyanide) complex 5 reacts with dmad to form [Ir(魏2-A2BPN)(CNtBu)2(dmad)]. On the whole, the electronic density provided to the metal by the [A2BPN]鈭?/sup> ligand is very sensitive to the coordination mode. The basicity of the new ligand is similar to that of the TpMe2 ligand in the 魏N,魏P mode but comparable to Tp if coordinated in the 魏N,魏P,畏2-C鈺怌 mode.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700