Methylidynephosphane Explained

Methylidynephosphane (phosphaethyne) is a chemical compound which was the first phosphaalkyne compound discovered, containing the unusual C≡P carbon-phosphorus triple bond. Although isolated samples of methylidynephosphane are impractical, other derivatives have been well studied such as tert-butylphosphaacetylene.

Description

Methylidynephosphane is the phosphorus analogue of hydrogen cyanide, with the nitrile nitrogen replaced by phosphorus. Methylidynephosphane can be synthesised via the reaction of phosphine with carbon,^[1] but it is extremely reactive and polymerises readily at temperatures above −120 °C. However, several types of derivatives, with bulky groups, such as tert-butyl or trimethylsilyl, substituted for the hydrogen atom, are much more stable, and are useful reagents for the synthesis of various organophosphorus compounds.^[2] The PCO⁻ and PCS⁻ anions are also known.^[3]

HCP has been detected in the interstellar medium.^[4]

History

While the existence of the molecule had been discussed,^[5] and early attempts had been made to prepare it, methylidynephosphane was first successfully synthesised in 1961, by T.E. Gier of E. I. duPont de Nemours, Inc.^[6] Earlier reports of preparing its sodium salt were reported as unreproducible by Gier. Methylidynephosphane may have contributed to an explosion that killed Vera Bogdanovskaia, an early chemist pursuing it, one of the first female chemists in Russia,^[7] and perhaps the first woman to die from her own research.^{[8] [9]}

Notes and References

1. Gier TE . HCP, A Unique Phosphorus Compound . . 1961 . 10.1021/ja01468a058 . 83 . 1769–1770 . 7.
2. Regitz M . Phosphaalkynes: new building blocks in synthetic chemistry . . 10.1021/cr00099a007 . 1990 . 90 . 191–213.
3. Hubler K, Schwerdtfeger P. . Theoretical Studies of NMR Chemical Shifts and Vibrational Frequencies in λ³-Phosphaalkynes P≡C-R . . 1999 . 38 . 157–164 . 10.1021/ic9811291.
4. 10.1086/519561 . Discovery of Phosphaethyne (HCP) in Space: Phosphorus Chemistry in Circumstellar Envelopes . 2007 . Agúndez . Marcelino . Cernicharo . José . Guélin . Michel . The Astrophysical Journal . 662 . 2 . L91–L94 . 2007ApJ...662L..91A . 10261/191973 . free .
5. H. Albers (1950) Angew. Chemie 62:443-467
6. Philip P. Power (1999) π-Bonding and the Lone Pair Effect in Multiple Bonds between Heavier Main Group Elements, Chem. Rev. 99(12):3463-3503, esp. 3491, see http://www.mycrandall.ca/faculty/MSchriver/coursewebs/ChemRev99LonePairPi.pdf, accessed 2 July 2014.
7. Book: Ledkovskaia-Astman. Marina. Rosenthal. Charlotte. Zirin. Mary Fleming. Dictionary of Russian Women Writers. 1994. Greenwood Publishing Group. Westport, CT. 978-0-313-26265-4.
8. Book: Rayner-Canham. Marelene . Rayner-Canham. Geoffrey. Women in Chemistry: Their Changing Roles from Alchemical Times to the Mid-twentieth Century. 2001. 64. Chemical Heritage Foundation. Philadelphia. 978-0-941901-27-7.
9. Book: Ogilvie. Marilyn. Harvey. Joy. Marilyn Bailey Ogilvie. Joy Harvey. Biographical Dictionary of Women in Science. 16 December 2003. 1135963436. 311. Routledge .