| Abstract: | The reactivity of LiSc(COT′′)2] ( 1 ; COT′′=1,4‐bis(trimethylsilyl)cyclooctatetraenyl) towards CoCl2 is considerably different from that of related lanthanide triple‐decker sandwich complexes. In addition to the expected triple‐decker complex Sc2(COT′′)3 ( 2 ), the complex Sc2{μ‐BTHP}(COT′′)2 ( 3 ) is formed, which comprises the novel BTHP2− ligand (BTHP2−=bis(3,5‐bis(trimethylsilyl)‐1,3a,6,6a‐tetrahydropentalene‐1‐yl)diide or bis(2,7‐bis(trimethylsilyl)bicyclo3.3.0]octa‐2,7‐dien‐4‐yl)diide, C16H10(SiMe3)42−). The formation of 3 is likely facilitated by the fact that scandium prefers η8,η3 coordination rather than highly symmetric η8,η8 coordination, and the η3‐coordinated COT′′ ligand in 1 is activated owing to a loss of aromaticity. Acid hydrolysis of 3 leads to air‐stable H2BTHP ( 4 ). |
