= Solution
Use an $\eta^5$ <cyclopentadienyl ligand> and four terminal <carbonyl ligands> at each <titanium>, with a Ti–Ti single <metal-metal bond>. The middle panel shows this connectivity. Neutral <electron counting> assigns five <electrons> to each Cp and gives
$$
\boxed{\mathrm{VE(Ti)}=4+5+4(2)+1=18.}
$$
Equivalently, the two Cp anions require an average <oxidation state> Ti(I), hence $d^3$; ionic counting gives $3+6+8+1=18$. \b[The formal Ti–Ti <bond order> is one.] The large coordination envelope can make this bond weak and long; reaching 18 <electrons> is bookkeeping, rather than proof of a short, strong bond. There is no need to invent extra CO bridges or a higher Ti–Ti <bond order>.
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