Tetraanionic Diphosphine Ligands with Borate-End Groups

Rayni P. Noriega, Devon Facchinato, and Marcus W. Drover*

Department of Chemistry, Western University, London, Ontario, N6A 3K7, Canada

Electrostatic forces influence each other according to Coulomb’s Law

Proposed ligand and substrate undergo oxidative addition. Charge can influence rate through attraction forces. Improving reactivity in this step indirectly improves cross-coupling reactions which are important for the production of pharmaceuticals that make use of new aryl-aryl bonds.

Previous synthesis of charged rhodium (I) octaboranyl complex by the Drover Group

Rhodium complex affected hydride transfer. Charged secondary coordination sphere (SCS) involved.

Synthesis of unsaturated diphosphine ligand starting materials

Tetraallylphosphinoethane ligand scaffold forms P2BCy4

Installing charge into diphosphine ligands with borate-end groups

Butylation of P2BCy4 forms {(P2BCy4)(nBu)4}4-

Charged nickel complex with tetraanionic diphosphine ligands

Formation of [Ni{(P2BCy4)(nBu)4}2]8-

Future work: oxidative addition studies

Proposed rate enhancement through ion-pairing interactions between catalyst

and substrate