The synthesis and reactivity of the end-on bound dinitrogen complex [(η 5-C 5H 3-1,3-(SiMe 3)2)2Ti] 2(μ 2,η 1,η 1-N 2) is described. The solid state structure of the dinitrogen compound reveals a weakly activated end-on bound N 2 ligand with an N-N bond length of 1.164(5) Å. Displacement of the N 2 ligand by organic azides has been used to prepare monomeric, base-free titanocene imido complexes, (η 5-C 5H 3-1,3-(SiMe 3)2)2Ti=NR (R = SiMe 3, 2,4,6-Me 3-C 6H 2). While unreactive toward C-H bonds, the Ti-N linkage is readily hydrogenated and participates in group transfer reactions with unsaturated organic molecules such as carbon monoxide and benzophenone. Reaction of the N 2 complex with Ph 2CN 2 allowed isolation of (η5-C 5H 3-1,3-(SiMe 3)2)2Ti(N 2CPh 2), which exists as a mixture of interconverting η 2 and n 1 isomers in solution. The diazoalkane complex also participates in "imido-like" reactivity, producing (η 5-C 5H 3-1,3-(SiMe 3)2)2Ti(NHN=CPh 2)H upon addition of H 2. Changing the diazoalkane to Me 3SiCHN 2 resulted in isolation of the double cyclometalated titanocene (η 5-C 5H 3-η 1-SiM 2CH 2-3-SiMe 3)2Ti, arising from facile intramolecular C-H activation of the cyclopentadienyl substituent by a transient titanocene alkylidene.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry