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Analysis of bonding in compound 1 using quantum chemical calculations. (A) Molecular graph of P(CtBu)3 (1) showing paths linking pairs of bonded atoms, bond critical points as small orange spheres, the phosphorus atom as a large orange sphere, carbon atoms as beige spheres, and hydrogen atoms as white spheres. (B) Standard heats of formation in kcal/mol at 298.15 K for tetrahedrane, P4, and phosphatetrahedrane from G3(MP2, CCSD(T)) calculations (25) performed using GAMESS (37). The phosphatetrahedrane ΔH∘f value can be approximated as the sum of three-quarters the value for tetrahedrane and one-quarter the value for the P4 molecule.

Image courtesy of the researchers.

Cummins paper published in Science Advances

by Danielle Doughty | Department of Chemistry |
Categories: Faculty, Research

The paper, Isolation of an elusive phosphatetrahedrane, was published online on March 25, 2020.

A paper authored by Martin-Louis Y. Riu, Rebecca L. Jones, Wesley J. Transue, Peter Müller and Christopher C. Cummins was published in Science Advances on March 25, 2020.

Isolation of an elusive phosphatetrahedrane
Martin-Louis Y. Riu, Rebecca L. Jones, Wesley J. Transue, Peter Müller and Christopher C. Cummins
Department of Chemistry, Massachusetts Institute of Technology, Cambridge MA, USA.
Science Advances  25 Mar 2020:
Vol. 6, no. 13, eaaz3168
DOI: 10.1126/sciadv.aaz3168

This exploratory synthesis investigation was undertaken to determine the viability of replacing a single carbon vertex with another p-block element in a highly strained tetrahedrane molecule. Phosphorus was selected for this purpose because the stable molecular form of elemental phosphorus is tetrahedral. Our synthetic strategy was to generate an unsaturated phosphorus center bonded to a substituted cyclopropenyl group, a situation that could lead to closure to provide the desired phosphatetrahedrane framework. This was accomplished by dehydrofluorination of the in situ generated fluorophosphine H(F)P(CtBu)3. Tri-tert-butyl phosphatetrahedrane, P(CtBu)3, was then isolated in 19% yield as a low-melting, volatile, colorless solid and characterized spectroscopically and by a single-crystal x-ray diffraction study, confirming the tetrahedral nature of the molecule’s PC3 core. The molecule exhibits unexpected thermal stability.

Read the Full Text at Science Advances.

Research in the Cummins group is focused on developing new methods of inorganic synthesis to address a variety of interesting questions.