Spectroscopic Identification of Trifluorosilylphosphinidene and Isomeric Phosphasilene and Silicon Trifluorophosphine Complex

Abstract

The perfluorinated silylphosphinidene, F3SiP, in the triplet ground state is generated by the reaction of laser-ablated silicon atoms with PF3 in solid neon and argon matrices. The reactions proceed with the initial formation of a silicon trifluorophosphine complex, F3PSi, in the triplet ground state, and a more stable inserted phosphasilene, FPSiF2, in the singlet ground state upon deposition. The trifluorosilylphosphinidene was formed through F-migration reactions of FPSiF2 and F3PSi following a two-state mechanism under irradiation with visible light (λ = 470 nm) and full arc light (λ > 220 nm), respectively. High-level quantum-chemical methods support the identification of F3PSi, FPSiF2, and F3SiP by matrix-isolation IR spectroscopy.

Generation and Identification of the Trifluorosilylarsinidene F3SiAs and Isomeric Perfluorinated Arsasilene FAsSiF2

“…Two absorption bands belong to anti-symmetric and symmetric stretching vibration modes of the SiF 2 moiety. The two frequencies are very close to that of FPSiF 2 (974.2, 933.1 cm À 1 , Ar-matrix; 978.5, 933.7 cm À 1 , Ne-matrix), [15] and lower that in F 2 Si=S (996, 969 cm À 1 , Ar-matrix) [19] but higher than that in SiF 2 (855, 843 cm À 1 , Ar-matrix; 864.6, 851.0 cm À 1 , Ne-matrix). [17] The AsÀ F stretching vibration was predicted at 648 cm À 1 as a medium strong absorption band and could not be clearly identified due to an overlap with the stronger IR bands of the precursor molecule AsF 3 in this region.…”

“…The photoisomerization of arsasilene FAsSiF 2 to F 3 SiAs is similar to the photochemistry of those phosphasilene, such as HPSiH 2 , FPSiF 2 , both of them isomerize to phosphinidene H 3 SiP and F 3 SiP under UV-vis light irradiation, respectively. [12,15] The calculated potential energy profile for the isomerization of FAsSiF 2 (Figure 2) unravels the underlying reaction mechanism. The spectra shown in Figure S1 and Figure S2 indicate that the arsasilene FAsSiF 2 molecule is produced by the reactions of ground state silicon ( 3 P) atoms with arsenic trifluoride AsF 3 in solid argon and neon matrices.…”

“…[13] Reactions of laser-ablated metal atoms (Ti, Zr, Hf, and Th) with arsenic trifluoride will form a terminal arsinidene molecule F 3 MÀ As in its triplet ground state, which were identified by matrixisolation infrared spectroscopy in conjunction with DFT calculations. [14] Inspired by the reaction of silicon atoms with PF 3 to form SiPF 3 , F 2 SiPF and F 3 SiÀ P, [15] our synthetic approach to silylarsinidene F 3 SiÀ As utilizes atomic silicon and AsF 3 as the precursors.…”

“…Considering the known photoinduced conversion from singlet FPSiF 2 to triplet F 3 SiP in low-temperature matrices. [15] DFT and coupledcluster calculations on the IR spectra of the most likely candidate species F 3 SiAs in the singlet and triplet states were performed (Table 1 and S1). In comparison to the experimentally observed spectra for the UV light (λ = 275 nm) photolysis products of FAsSiF 2 , the bands observed in Ar matrices are reasonably assigned to the arsinidene intermediate F 3 SiAs in the triplet ground state based on the good agreement with the predicted three strongest IR bands at 973, 858, and 476 cm À 1 , respectively.…”