The titanocene dinitrogen complex [(η5-C5H 2-1,2,4-Me3)2Ti]2(μ2, η2,η2-N2) (1-N2) has been prepared both by dihydrogen reductive elimination from the in situ generated monohydride derivative and by alkali metal reduction of the corresponding monoiodide. In the solid state, 1-N2 contains a side-on bound N 2 ligand with an N-N bond length of 1.216(3) Å, consistent with a significant contribution from a two-electron-reduced diazenido ([N 2]2-) fragment. Attempts to maintain side-on coordination of the N2 ligand but increase the wedge dihedral by introducing isopropyl or tert-butyl substituents induced a change in hapticity to end-on and a less activated bridging dinitrogen ligand. The ansa-titanocene dinitrogen complexes rac-[Me2Si(η5-C5H 2-2-SiMe3-4-tBu)2Ti] 2(μ2,η1,η1-N 2)(4-N2) and [Me2Si(η5-C 5Me4)(η5-C5H33- tBu)Ti]2(μ2,η1, η1-N2) (5-N2) have also been prepared and crystallographically characterized and shown to have weakly activated, end-on dinitrogen ligands. The latter example coordinates two additional equivalents of N2 upon cooling under a dinitrogen atmosphere in pentane solution.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry