Arsaalkyne

Chemical structure of the arsaalkyne As≡C−C6H2-2,4,6-(t-Bu)3.

In chemistry, a arsaalkyne (IUPAC name: alkylidynearsane) is an organoarsenic compound containing a triple bond between arsenic and carbon with the general chemical formula R−C≡As. Arsaalkynes are rare, especially in comparison with the phosphaalkynes. The parent H−C≡As has been characterized spectroscopically, otherwise the only arsaalkynes have bulky organic substituents.

Synthesis and isolation

Arsaalkynes are produced by dehydrohalogenation or related base-induced elimination reactions. The case of HCAs is illustrative:

Cl−CH2−AsH2 + 2 Na2CO3 → H−C≡As + 2 NaHCO3 + 2 NaCl

Owing to the principles of the double bond rule, arsaalkynes tend to oligomerize more readily than the phosphorus analogues. Thus attempts to prepare Me3C−C≡As produce the tetramer, which has a cubane structure. The very bulky substituent −C6H2-2,4,6-(t-Bu)3 does however allow the crystallization of the monomeric arsaalkyne. Its As-C bond length is 1.657(7) Å.

See also

References

  1. ↑ Guillemin, Jean-Claude; Chrostowska, Anna; Dargelos, Alain; Nguyen, Thi Xuan Mai; Graciaa, Alain; Guenot, Pierre (2008). "Methylidynearsine (HC≡As): Synthesis and Direct Characterization by UV-Photoelectron Spectroscopy and Mass Spectrometry". Chemical Communications (35): 4204–4206. doi:10.1039/B806771F. PMID 18802530.
  2. ↑ Hitchcock, Peter B.; Johnson, Julian A.; Nixon, John F. (1993). "Synthesis and Structure of the Arsaalkyne Tetramer (AsCtBu)4 and its Fe(CO)4 Derivative". Angewandte Chemie International Edition in English. 32: 103–104. doi:10.1002/anie.199301031.
  3. ↑ Hitchcock, Peter B.; Jones, Cameron; Nixon, John F. (1994). "Synthesis, Crystal and Molecular Structure of the First Metal Complex [Pt(PPh3)2{η2-As≡C(C6H2But3)}] Derived from an Arsaalkyne". J. Chem. Soc., Chem. Commun. (18): 2061–2062. doi:10.1039/C39940002061.