Magnesium Promoted Active and Isoselective ROP of <i>rac</i>‐Lactide and ϵ‐Caprolactone Under Mild Conditions
Shweta Sagar, Kulsum Bano, Alok Sarkar, Kuntal Pal, Tarun K. Panda
Abstract
Abstract A novel amidophosphine sulfur‐supported magnesium complex, [Ph 2 P(S)NCH 2 CH 2 N−(CH 2 CH 2 )O]Mg(C 4 H 9 )(THF)] ( 2 ) enabling efficient ring‐opening polymerization of rac ‐lactide (LA) and ϵ‐caprolactone (CL) is disclosed. Achieved incredible selectivity for ROP of rac ‐lactide for the first time using a magnesium catalyst affording isoselective PLA with a P i value of 0.77. The polymerization of rac ‐LA as well as ϵ‐CL proceeded under mild reaction conditions in absence of any external initiator, to yield corresponding polyesters with a great control over the molecular weight. The kinetic studies reveal that both sulfur and magnesium centers simultaneously work together to drive high yield and selectivity.