Tetrarhena-heterocycle from the Palladium-Catalyzed Dimerization of Re2(CO)8(μ-SbPh2)(μ-H) Exhibits an Unusual Host–Guest Behavior

The six-membered heavy atom heterocycles [Re2(CO)8(μ-SbPh2)(μ-H)]2, 5, and Pd[Re2(CO)8(μ-SbPh2)(μ-H)]2, 7, have been prepared by the palladium-catalyzed ring-opening cyclo-dimerization of the three-membered heterocycle Re2(CO)8(μ-SbPh2)(μ-H), 3. The palladium atom that lies in the center of the heterocycle 7 was removed to yield 5. The palladium removal was found to be partially reversible leading to an unusual example of host–guest behavior. A related dipalladium complex Pd2Re4(CO)16(μ4-SbPh)(μ3-SbPh2)(μ-Ph)(μ-H)2, 6, was also formed in these reactions of palladium with 3.本研究通过三元杂环化合物Re₂(CO)₈(μ-二苯基锑基)(μ-氢)（编号为3）的钯催化开环环二聚反应，成功制备得到六元重原子杂环类二聚体[Re₂(CO)₈(μ-二苯基锑基)(μ-氢)]₂（编号为5）与Pd[Re₂(CO)₈(μ-二苯基锑基)(μ-氢)]₂（编号为7）。将位于杂环7中心的钯原子移除后即可得到化合物5；实验发现该脱钯过程具有部分可逆性，由此得到一例罕见的主客体行为实例。此外，在钯与化合物3的反应体系中，还同步生成了相关二钯配合物Pd₂Re₄(CO)₁₆(μ₄-苯基锑)(μ₃-二苯基锑基)(μ-苯基)(μ-H)₂（编号为6）。