The Stability of Diphosphino-Boryl PBP Pincer Backbone: PBP to POP Ligand Hydrolysis

Since moisture may frequently be present in many solvents, it is important to know the reactivity of a catalyst against water for catalytic reactions. In order to explore the stability and understand the transformation process of diphosphino-boryl-based PBP pincer platform, [PdCl{B((NCH2PBu2)-Bu-t)(2)-o-C6H4}] (1) was treated with PdCl2, HB(NCH2PPh2)(2)-o-C6H4 was reacted with [PdCl2(cod)] (cod=cyclo-octa-1,5-diene) and [Pd-2(dba)(3)] (dba=dibenzylideneacetone), respectively, in the presence of water. Some novel palladium POP complexes, [Pd2Cl2(mu-Cl){mu-kappa(3)-P,O,P-OB((NCH2PBu2)-Bu-t)(2)-o-C6H4}] (2 a), [Pd-4(mu-Cl)(2)(mu-O)(2){mu-kappa(3)-P,O,P-OB(NCH2PPh2)(2)-o-C6H4}(2)] (2 b), [Pd-2{mu-kappa(4)-P,P,P,P-O(B(NCH2PPh2)(2)-o-C6H4)(2)}{mu-kappa(2)-P,P-(NHCH2PPh2)(2)-o-C6H4}] (3), were obtained. It was found that the PBP pincer backbone can easily be converted into a POP backbone in the presence of water. From the crystal structures of the resultant palladium complexes, possible pincer backbone transformation pathways were discussed.

Automated summary

This study investigated the stability and transformation process of the diphosphino-boryl-based PBP pincer platform in the presence of water, revealing that the PBP pincer backbone can easily be converted into a POP backbone. By analyzing the crystal structures of the resulting palladium complexes, possible pathways for pincer backbone transformation were discussed.