| π-bonded manganese arene complexes are very interesting in organometallic chemistry and have a great use in organic synthesis. Recently it was found that chemical reducing agents could convert (polyarene)Mn(CO)3 + into a novel syn-facial bimetallic η4-η6 naphthalene complexes. However, the reduction of a benzothiophene complex afforded a high yield of product with a Mn(CO)4 moiety inserting into the C(aryl)-S bond. This compound serves as a good model for catalytic deep hydrodesulfurization (HDS). Chemical reduction of coordinated 2,7-dimethylbenzothiophene easily led to three products, one of which was a novel bimetallic compound with S bonded by two manganeses. The reduction mechanism was also presented.; Besides electrons, weak nucleophiles such as Pt(PPh3) 2 can also induce the C(vinyl)-S bond activation. [2-MeBTMn(CO) 3]+ reacted with Pt but gave an insertion compound with C(aryl)-S bond activation. This is surprising because this regioselectivity has never been observed and the C(aryl)-S bond was supposed to be much stronger than the C(vinyl)-S bond. Extension of this chemistry to other methylated BT and alkyl DBT gave interesting regiochemistry and the insertion mechanism was studied.; Mn mediated C-S bond activation indeed led to desulfurization under hydrogen sources. For example the Pt insertion product could easily be desulfurized. Studies above have shown that bimetallic system is important for the desulfurization of BT. One way to improve the catalysts for deep HDS is to prepare the bimetallic catalyst in the form of nanoparticles. So nanoparticle of PtFe was tried, which seemed promising for next generation of catalysts for HDS. |
