Pentaphenylantimony

Pentaphenylantimony
Names
Preferred IUPAC name
Pentaphenyl-λ5-stibane
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/5C6H5.Sb/c5*1-2-4-6-5-3-1;/h5*1-5H;
    Key: XJQGITRIKZCKRF-UHFFFAOYSA-N
  • C1=CC=C(C=C1)[Sb](C2=CC=CC=C2)(C3=CC=CC=C3)(C4=CC=CC=C4)C5=CC=CC=C5
Properties
C30H25Sb
Molar mass 507.290 g·mol−1
Related compounds
Other cations
 PPh5
AsPh5
BiPh5
Related compounds
 Pentamethylantimony
Pentaethylantimony
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Pentaphenylantimony is an organoantimony compound containing five phenyl groups attached to one antimony atom. It has formula Sb(C6H5)5 (or SbPh5).

Structure

The structure of pentaphenylantimony has been the subject of several studies, and a definite ground state remains uncertain. The molecule adopts a roughly square pyramidal shape in the unsolvated crystal. In crystals of the solvate with cyclohexane or tetrahydrofuran, the compound adopts a trigonal bipyramid shape.[1] When dissolved, molecules are also trigonal bipyramidal.[1] According to solution NMR measurements, the phenyl groups all appear to be equivalent, indicating fluxionality.[2]

Solid pure pentaphenylantimony forms triclinic crystals in the P1 space group. The unit cell has a=10.286 b=10.600 and c=13.594 Å, α=79.20° β=70.43° γ=119.52°. The basal Sb-C bond length is 2.216 Å whereas the apex Sb-C length is 2.115 Å.[3]

Reactions

Pentaphenylantimony reacts with a variety of protic reagents (hydrogen halides, carboxylic acids, methanol, etc). Benzene is one product as well as a tetraphenylantimony(V) compound:[4]

Ph5Sb + HOR → PhH + Ph4SbOR
Ph5Sb + HX → PhH + Ph4SbX

Halogens also cleave one Sb-phenyl bond:

Ph5Sb + X2 → PhX + Ph

When heated, pentaphenylantimony forms triphenylstibine, biphenyl and p-quaterphenyl.[5]

A reaction with carbon tetrachloride yields tetraphenylstibonium chloride, chlorobenzene, and benzene. Some of these reactions may proceed by radical pathways.[5]

Formation

Pentaphenylantimony can be formed by reacting dichlorotriphenylantimony with phenyl lithium.[3]

References

  1. ^ a b Lindquist-Kleissler, Brent; Weng, Monica; Le Magueres, Pierre; George, Graham N.; Johnstone, Timothy C. (2021-06-21). "Geometry of Pentaphenylantimony in Solution: Support for a Trigonal Bipyramidal Assignment from X-ray Absorption Spectroscopy and Vibrational Spectroscopic Data". Inorganic Chemistry. 60 (12): 8566–8574. doi:10.1021/acs.inorgchem.1c00496. ISSN 0020-1669. PMID 34087066. S2CID 235346648.
  2. ^ Beattie, I. R.; Livingston, K. M. S.; Ozin, G. A.; Sabine, R. (1972). "The shape of pentaphenylantimony and pentaphenylarsenic in solution". Journal of the Chemical Society, Dalton Transactions (7): 784. doi:10.1039/DT9720000784.
  3. ^ a b Beauchamp, A. L.; Bennett, Michael J.; Cotton, F. Albert (November 1968). "A reinvestigation of the crystal and molecular structure of pentaphenylantimony". Journal of the American Chemical Society. 90 (24): 6675–6680. doi:10.1021/ja01026a020.
  4. ^ Sharutin, V. V.; Sharutina, O. K.; Gubanova, Yu. O.; El'tsov, O. S. (September 2019). "Specific Features of the Reaction between Pentaphenylantimony and Bifunctional Acids: Structures of Bis(tetraphenylantimony) Glutarate, Benzene Solvate of Bis(tetraphenylantimony) 1,4-Cyclohexanedicarboxylate, Dioxane Solvate of Triphenylantimony Hydroxybenzoate, and Triphenylantimony 3-Hydroxybenzoate Adduct with Tetraphenylantimony Tetraphenylstiboxybenzaote and Toluene". Russian Journal of Inorganic Chemistry. 64 (9): 1138–1145. doi:10.1134/S0036023619090195. S2CID 203852991.
  5. ^ a b Shen, Kei-Wei; McEwen, William E.; Wolf, Alfred Peter (March 1969). "Photolysis and thermolysis of pentaphenylantimony in benzene". Journal of the American Chemical Society. 91 (6): 1283–1288. doi:10.1021/ja01034a003.

Further reading

  • Smirnova, N.N.; Letyanina, I.A.; Larina, V.N.; Markin, A.V.; Sharutin, V.V.; Senchurin, V.S. (January 2009). "Thermodynamic properties of pentaphenylantimony Ph5Sb over the range from T→0K to 400K". The Journal of Chemical Thermodynamics. 41 (1): 46–50. doi:10.1016/j.jct.2008.08.002.
  • Brock, C. P.; Ibers, J. A. (1976-01-01). "The role of crystal packing forces in the structure of pentaphenylantimony". Acta Crystallographica Section A. 32 (1): 38–42. Bibcode:1976AcCrA..32...38B. doi:10.1107/S0567739476000065.