title: A Molecular Precursor to Phosphaethyne and Its Application in Synthesis of the Aromatic 1,2,3,4-Phosphatriazolate Anion.
abstract: Dibenzo-7-phosphanorbornadiene Ph3PC(H)PA (1, A = C14H10, anthracene) is reported here as a molecular precursor to phosphaethyne (HC≡P), produced together with anthracene and triphenylphosphine. HCP generated by thermolysis of 1 has been observed by molecular beam mass spectrometry, laser-induced fluorescence, microwave spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. In toluene, fragmentation of 1 has been found to proceed with activation parameters of ΔH(⧧) = 25.5 kcal/mol and ΔS(⧧) = -2.43 eu and is accompanied by formation of an orange insoluble precipitate. Results from computational studies of the mechanism of HCP generation are in good agreement with experimental data. This high-temperature method of HCP generation has pointed to new reaction chemistry with azide anion to produce the 1,2,3,4-phosphatriazolate anion, HCPN3(-), for which structural data have been obtained in a single-crystal X-ray diffraction study. Negative-ion photoelectron spectroscopy has shown the adiabatic detachment energy for this anion to be 3.555(10) eV. The aromaticity of HCPN3(-) has been assessed using nucleus-independent chemical shift, quantum theory of atoms in molecules, and natural bond orbital methods.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Wesley J
authors.initials: WJ
authors.lastname: Transue
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Velian
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Matthew
authors.initials: M
authors.lastname: Nava
authors.affiliation: Harvard-Smithsonian Center for Astrophysics , Cambridge, Massachusetts 02138, United States.
authors.forename: Marie-Aline
authors.initials: MA
authors.lastname: Martin-Drumel
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Caroline C
authors.initials: CC
authors.lastname: Womack
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Physical Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Gao-Lei
authors.initials: GL
authors.lastname: Hou
authors.affiliation: Physical Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Wang
authors.affiliation: Harvard-Smithsonian Center for Astrophysics , Cambridge, Massachusetts 02138, United States.
authors.forename: Michael C
authors.initials: MC
authors.lastname: McCarthy
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Field
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Cummins