Transition metal fullerene complex

Source: Wikipedia, the free encyclopedia.
Fullerenes are typically spheroidal carbon compounds, the most prevalent being buckminsterfullerene, C60.[2]

One year after it was prepared in milligram quantities in 1990,[3] C60 was shown to function as a ligand in the complex [Ph3P]2Pt(η2-C60).[4]

Since this report, a variety of

transition metals and binding modes were demonstrated. Most transition metal fullerene complex are derived from C60, although other fullerenes also coordinate to metals as seen with C70Rh(H)(CO)(PPh3)2.[5]

Binding modes

As ligands, fullerenes behave similarly to

metal-alkene complexes. They almost always coordinate in a dihapto fashion and prefer electron-rich metal centers.[6] This binding occurs on the junction of two 6-membered rings. Hexahapto and pentahapto bonding is rarely observed.[7]

In Ru3(CO)9(C60), the fullerene binds to the triangular face of the cluster.[8]

  • Illustrative Fullerene Complexes
  • [[Ph3P]2Pt]6(η2-C60)
    [[Ph3P]2Pt]6(η2-C60)
  • Ru3(CO)9(C60)
    Ru3(CO)9(C60)
  • Platinum complex of isoxazoline-modified fullerene.
    Platinum complex of isoxazoline-modified fullerene.

Examples

C60 forms stable complexes of the type M(C60)(diphosphine)(CO)3 for M = Mo, W. A dirhenium complexes is known with the formula Re2(PMe3)4H8(η2:η2C60) where two of the hydrogen act as bridging ligands.[5]

Many fullerene complexes are derived from platinum metals. An unusual cationic complex features three 16e Ru centers:

3 Cp*Ru(MeCN)3+ + C60 → {[(Cp*Ru(MeCN)2]3C60}3+ + 3 MeCN

Vaska's complex forms a 1:1 adduct, and the analogous IrCl(CO)(PEt3)2 binds 200x more strongly.[2] Complexes with more than one fullerene ligand are illustrated by Ir4(CO)3(μ4-CH)(PMe3)2(μ-PMe)2(CNCH2Ph)(μ-η2:η2C60)(μ4-η1:η1:η2:η2C60). In this Ir4 cluster two fullerene ligands with multiple types of mixed binding. Platinum, palladium, and nickel form complexes of the type C60ML2 where L is a monodentate or bidentate phosphorus ligand.[5] They are prepared by displacement of weakly coordinating ligands such as ethylene:[6]

[Ph3P]2Pt(C2H4) + C60 → [Ph3P]2Pt(η2-C60) + C2H4

In [(Et3P)2Pt]6(η2-C60), six Pt centers are bound to the fullerene.[9]

Modified fullerenes as ligands

Osmium tetraoxide adds to C60 to give, in the presence of pyridine (py), the diolate C60O2OsO2(py)2.[2]

The pentaphenyl anion C60Ph5− behaves as a cyclopentadienyl ligand.[5]

Ferrocene-like complex of C60Ph5−.

In this example, the binding of the ligand is similar to

indenyl-like ligand.[10]
Fullerenes can also be substituents on otherwise conventional ligands as seen with an isoxazoline fullerene chelating to platinum, rhenium, and iridium compounds.[11]

Ongoing research

Although no application has been commercialized.

non-linear optical (NLO) materials,[12] and as supramolecular building blocks.[13]

See also

References

  1. doi:10.1021/ic00101a015
    .
  2. ^
    PMID 11848962
    .
  3. doi:10.1016/0009-2614(90)87109-5
    .
  4. S2CID 95654230
    .
  5. ^
    S2CID 56103986
    .
  6. ^ a b Spessard, p. 162
  7. ^ Spessard, p. 165
  8. doi:10.1021/ja962077m
    .
  9. doi:10.1021/ja00024a079
    .
  10. doi:10.1016/S0022-328X(03)00465-0
    .
  11. doi:10.1021/om200238a
    .
  12. doi:10.1016/j.ica.2011.10.018
    .
  13. doi:10.1016/j.tet.2010.10.066
    .

Bibliography
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