Pentaphenylantimony

Pentaphenylantimony

Names
Preferred IUPAC name Pentaphenyl-λ5-stibane
Identifiers
CAS Number	2170-05-0  N
3D model (JSmol)	Interactive image
ChemSpider	9987829
PubChem CID	11813170
CompTox Dashboard (EPA)	DTXSID60473337
InChI InChI=1S/5C6H5.Sb/c5*1-2-4-6-5-3-1;/h5*1-5H; Key: XJQGITRIKZCKRF-UHFFFAOYSA-N
SMILES C1=CC=C(C=C1)[Sb](C2=CC=CC=C2)(C3=CC=CC=C3)(C4=CC=CC=C4)C5=CC=CC=C5
Properties
Chemical formula	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). Infobox references

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. 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. 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. Bibcode:1968JAChS..90.6675B. 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. 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. Bibcode:1969JAChS..91.1283S. 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.