Bis(pentalene)di-titanium: a bent double-sandwich complex with a very short Ti-Ti bond

The novel bimetallic bis(pentalene) complex Ti-2(mu g(5), eta(5)- Pn(+))(2) (Pn(+) = C8H4((SiPr3)-Pr-i-1,4)(2)) has been synthesised and structurally characterised. Structural data show a Ti-Ti distance of 2.399(2) angstrom, consistent with a strong metal-metal interaction, which DFTcalculations best describe as a double bond with sigma and pi components.