Insertion of phenyl isocyanate into mono- and diaminosilanes

The aminosilanes MenSi(NRR')(4-n) (n=2,3) with NRR'= ethylamino (NHEt), n-propylamino ((NHPr)-Pr-n), sec-butylamino n-octylamino (NI-InOct), n-dodecylamino (NH(n)Dodec), allylamino (NHA11), tert-butylamino (NH(t)Mu), diethylamino (NFt(2)), and anilino (NHPh) were synthesized and their reactions with phenyl isocyanate were studied. In all cases of these silanes Me,SiN RR' and Me2Si(NRR'), formal insertion of the -NCO group into their Si-N bonds was observed, i.e. formation of products with Si-N (rather than Si-O) bonds was found. In some cases, the products could be crystallized and their molecular structures have been elucidated with single-crystal X-ray diffraction analyses.