Preparation and Photochemistry of Parent Triplet Vinylarsinidene

Abstract

Vinyl pnictinidenes are an elusive family of molecules that have been suggested as key intermediates in multiple chemical reactions and commonly display a predisposition toward open-shell electronic ground states (as is evident from quantum chemical computations). However, owing to their expected extremely high reactivity, no vinyl pnictinidene has ever been isolated and characterized spectroscopically. Here, we report the synthesis and spectroscopic characterization of vinylarsinidene, a higher congener of vinylnitrene. As we demonstrate, triplet vinylarsinidene can be prepared through the low-temperature photolysis of diazidovinylarsine at 10 K in an argon matrix. The title compound can also be generated through high-vacuum flash pyrolysis of the diazide at 700 °C and trapped analogously. Triplet vinylarsinidene was characterized by IR and UV/vis spectroscopy and displayed remarkably rich unimolecular photochemistry. Upon selective photoirradiation, it rearranges to vinylidenearsine, 2H-arsirene, triplet ethynylarsinidene or an arsinidene (H−As) acetylene complex. The formation mechanisms of these products were rationalized with DFT and CASPT2 computations.

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

“…Observed Calculated Modes [d] Ne-matrix Ar-matrix CCSD(T)-F12 [b,c] FAsSiF 2 - [a] 968 Similar to other reported arsinidenes, such as PhAs, [3] C 2 H 3 As, [9] and HCCAs, [10] which have been identified to show a triplet ground state, the trifluorosilylarsinidene F 3 SiAs is also computed to show a 3 A 1 ground state with C 3v symmetry. The predicted singlet-triplet energy gap ΔE ST of trifluorosilylphosphinidene is 27.0 kcal mol À 1 at B3LYP/aug-cc-pVTZ and 24.3 kcal mol À 1 at CCSD(T)-F12/aug-cc-pVTZ level.…”

“…The parent arsinidens diradical, HÀ As (1), has been produced by photolysis of AsH 3 , and detected by IR, Raman and microwave spectroscopy (Scheme 1). [8] Very recently, triplet phenylarsinidene PhÀ As (2) [3] and parent vinylarsinidene C 2 H 3 À As (3) [9] have been generated in an argon matrix through the photolysis of corresponding arsenic diazide. In addition, the phenylarsinidene oxidation to dioxophenylarsine and the rich unimolecular photochemistry of vinylarsinidene were observed.…”

Recent advances in the chemistry of isolable carbene analogues with group 13–15 elements

“…This species was generated in situ through the decarbonylation of an arsaketene and was subsequently ensnared using various Lewis bases. 367 More recently, Mardyukov synthesized and spectroscopically characterized a triplet vinylnitrene, 368 demonstrating its existence and stability. This compound can be prepared through low-temperature photolysis of diazidovinylarsine or via high-vacuum flash pyrolysis of the diazide.…”