Reaction Control of Organopaliadium Complexes by Using Bidentate Porphyrin Ligand

由于卟啉配体的四齿性质，卟啉有机配合物在金属有机化学中是一种非常罕见的化合物。然而，双齿卟啉的有机金属配合物的结构和反应是非常感兴趣的，鉴于其作为功能化合物的实用性。本文研究了N^<21>，N^<22>-桥联卟啉双齿钯配合物的化学性质。双齿卟啉钯配合物的配位化学一般来说，与膦配体相比，氮配体与钯的配位较弱。我们发现双齿卟啉与钯的配位作用比一般的双齿氮配体如联吡啶强得多。此外，NMR中的环电流效应和UV-vis中的Soret带有助于阐明Pd配位球的结构和反应.研究了（π-烯丙基）钯卟啉配体的配位动力学。π-烯丙基配体的这种顺反异构化通过一个Pd-N键的解离而发生。该过程的活化能比相应的联吡啶络合物的活化能大20 Kcal/mol. CO、异氰化物和烯烃在Pd-甲基键（乙酰基）Pd和（甲基亚氨基）Pd配合物中的插入反应产率很高，通过中间体配合物的分离和精确的动力学测量，阐明了插入反应的机理。通过苯乙烯插入Pd-甲基键和Pd-乙酰键合成了（π-苄基）Pd卟啉。通过X射线晶体学和核磁共振谱研究了π-苄基配体的动力学行为.双齿卟啉铑配合物的合成研究了双齿卟啉铑配合物的分子结构。

Organometallic complexes of porphyrins have been rather of unusual in organometallic chemistry because of the tetradentate nature of porphyrin ligand. However, structure and reaction of organometallic complexes with bidentate porphyrin is of great interest in view of its utility as a functional compound. The chemistry of Pd complexes of N^<21>, N^<22>-bridged porphyrin as a bidentate ligand has been studied in this work.1. Coordination chemistry of Pd complexes of bidentate porphyrinGenerally speaking, nitrogen donor ligand weakly coordinates to Pd in comparison with phosphine ligand. We have found that coordination of bidentate porphyrin to Pd is much stronger than that of ordinary bidentate nitrogen ligand such as bipyridine. Furthermore, ring current effect in the NMR and Soret band in UV-vis are helpful in elucidating structure and reaction of Pd coordination sphere.2. Reaction behavior of (π-allyl)Pd porphyrinCoordination dynamics of the π-allyl ligand of Pd porphyrin has been studied. This cis-trans isomerization of the π-allyl ligand occurs by way of dissociation of one Pd-N bonding. Activation energy of this process is by 20 Kcal/mol larger in comparison with that of the corresponding bipyridine complex.3. Insertion reaction of CO, isocyanide, and alkenes into Pd-methyl bond(Acetyl)Pd and (methylimino)Pd complexes have been obtained in good yield and mechanism for the insertion process have been elucidated through the isolation of intermediate complexes and precise kinetic measurements. (π-Benzyl)Pd porphyrins have been prepared by the insertion of styrenes into Pd-methyl and Pd-acetyl bonds. Dynamic behavior of the π-benzyl ligand was elucidated by X-ray crystallography and NMR measurement.4. Synthesis of rhodium complexes of bidentate porphyrinsMolecular structures of Rh complexes of the bidentate porphyrin have been shown.