Bis(2,4,6-triisopropylphenyl)tin(IV) compounds: Synthesis, single-crystal X-ray characterization and reactivity toward ionizing species and polar monomers

Abstract The synthesis of new organotin compounds of general formula Tip 2 SnRR′ (Tip = 2,4,6-triisopropylbenzene; R = R′ = CH 3 ( 1 ); R = R′ = CH CH 2 ( 2 ); R = CH 2 Ph, R′ = Br ( 3 ); R = R′ = CH 2 CH CH 2 ( 4 )) is described herein. The compounds have been characterized by 1 H, 13 C, 119 Sn NMR, mass spectroscopy and elemental analysis. Characterization by single-crystal X-ray diffraction analysis has been obtained for compounds 2 , 3 and 4 . The reactivity with ionizing agents has been studied by NMR spectroscopy. Compounds 2 and 4 underwent alkyl abstraction by [(CH 3 CH 2 ) 3 Si] + [B(C 6 F 5 ) 4 ] − affording stable cationic species ( 2a , 4a ). For the cationic specie 4a a π-interaction of the benzyl group to the metal centre was recognized by solution NMR studies. A cationic species ( 3a ) was generated from compound 3 using AgSbF 6 as ionizing agent. The cationic species ( 2a , 3a ) exhibited moderate activity as initiator in the cationic polymerization of 1,4-butadiene and good activity in the ring opening polymerization (ROP) of propylene oxide and e-caprolactone.