“…2e-j), leading to a more ionic bonding character of Fe-Cp and more covalent bonding characters of Fe-graphene. Different from the FeBz@G isomer, 28 the D Fe-Cp of FeCp@G 33 -S is a bit larger, $1.76Å, whereas a different case is veried for that of D Fe-G , $1.64Å. Compared with that of FeCp@G 33 -S, the D Fe-G of (FeCp) 2 @G 33 -D 1 is much larger, $1.69Å, whereas for the (FeCp) 2 @G 33 -D 2 and (FeCp) 2 @G 33 -D 3 isomers, the D Fe-G s are reduced sharply to 1.60Å (see Table 1).…”