文摘
The reaction of the low valent metallocene(II) sources Cp鈥?sub>2Ti(畏2-Me3SiC2SiMe3) (Cp鈥?= 畏5-cyclopentadienyl, 1a or 畏5-pentamethylcyclopentadienyl, 1b) with different carbodiimide substrates RN鈺怌鈺怤R鈥?2-R-R鈥?(R = t-Bu; R鈥?= Et; R = R鈥?= i-Pr; t-Bu; SiMe3; 2,4,6-Me-C6H2 and 2,6-i-Pr-C6H3) was investigated to explore the frontiers of ring strained, unusual four-membered heterometallacycles 5-R. The product complexes show dismantlement, isomerization, or C鈥揅 coupling of the applied carbodiimide substrates, respectively, to form unusual mono-, di-, and tetranuclear titanium(III) complexes. A detailed theoretical study revealed that the formation of the unusual complexes can be attributed to the biradicaloid nature of the unusual four-membered heterometallacycles 5-R, which presents an intriguing situation of M鈥揅 bonding. The combined experimental and theoretical study highlights the delicate interplay of electronic and steric effects in the stabilization of strained four-membered heterometallacycles, accounting for the isolation of the obtained complexes.
