Troticene
Other names: (Cycloheptatrienyl)(cyclopentadienyl)titanium
C12H12Ti
24/50 
common
Troticene is a mixed-ring metallocene featuring a titanium atom sandwiched between a cyclopentadienyl and a cycloheptatrienyl (tropylium) ring. Synthesized in the early 1960s as part of the expanding field of organometallic chemistry, it's structurally similar to trovacene but contains titanium instead of vanadium. Troticene appears as an air-sensitive dark crystalline solid. Its unusual structure, with rings of different sizes, creates distinctive electronic properties that differ from symmetric metallocenes like ferrocene. This compound represents an important entry in the family of mixed-sandwich complexes that helped expand understanding of metal-ligand bonding in organometallic chemistry.