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

The synthesis of new organotin compounds of general formula Tip2SnRR′ (Tip = 2,4,6-triisopropylbenzene; R = R′ = CH3 (1); R = R′ = CHdouble bond; length as m-dashCH2 (2); R = CH2Ph, R′ = Br (3); R = R′ = CH2CHdouble bond; length as m-dashCH2 (4)) is described herein. The compounds have been characterized by 1H, 13C, 119Sn 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 [(CH3CH2)3Si]+[B(C6F5)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 AgSbF6 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 ε-caprolactone.