A Silyl Radical formed by Muonium Addition to a Silylene

Abstract

Rekordradikal: Die Bestrahlung des stabilen Silylens N,N′‐Bis(2,6‐diisopropylphenyl)‐1,3‐diaza‐2‐silacyclopent‐4‐en‐2‐yliden mit Myonen führt zu einem Radikal, das anhand seines Myonenspinrotations(μSR)‐Spektrums als das monomere Myonium‐Addukt identifiziert wurde. Die Myon‐Hyperfeinkonstante für dieses Radikal beträgt 931 MHz – der höchste je bestimmte Wert für ein freies Radikal.

Free Radical Reactivity of Mono‐ and Dichlorosilylene with Muonium

“…The optimised geometry has a fixed conforma- [15] In summary, we have employed muonium to explore the free radical reactivity of two novel chlorosilylenes. Spectroscopic and computational investigations show that Mu adds to the silicon in the NHC-stabilised dichlorosilylene (8). In contrast, Mu reacts at the carbon of a siladiazirene ring in the monochlorosilylene (7).…”

“…The largest substituent (2,6-diisopropylphenyl) served to slow the silyl coupling reaction so that we were able to detect the primary silyl radical 5, as evident from the record high hfc (931 MHz). [8] In a related study [9] we explored the relative reactivity of carbon and silicon atoms in a silene 6, this being the product of trimethylsilyl migration in silylene 3. [5] We now report our investigation of the reactivity of two novel chlorosilylenes, 7 [10] and 8 [11] (Scheme 2).…”

Anorganische Chemie 2010

“…Ge‐Atom sinkt, und dass mit der Ordnungszahl die Delokalisierung über den fünfgliedrigen Ring zunimmt 1_36. Ein Silylradikal erhält man auch durch Addition eines Myons an ein N‐heterocyclisches Silylen 1_37. Ungewöhnliche Bindungsverhältnisse zeichnen ein Disilanyldianion (34) aus, in dem beide Siliciumzentren pentakoordiniert vorliegen.…”

Observation of a Metastable P‐Heterocyclic Radical by Muonium Addition to a 1,3‐Diphosphacyclobutane‐2,4‐diyl

“…In this study,w ee mployed the air-stable 1,3-diphosphacyclobutane-2,4-diyl 1 (Figure 1) [8,9,22] and 1,3,5-tri-t-butylbenzene (Mes*H) for mSR spectroscopy.T he data obtained from 1,bearing the Mes* substituents and benzyl group,were expected to be easily analyzed by utilizing the information about Mes*H. Abrief description of the mSR techniques used in this study is given in the Supporting Information and in the literature. [16][17][18][19][20] Themuon beamline at the TRIUMF cyclotron (M15) was used, and the Helios spectrometer was equipped with the superconducting solenoid magnet. Thec ompound 1 was prepared according to the literature.…”

“…[18] Also,i tis noteworthy that West and Percival utilize muonium for elucidating radical reactions of particular silicon-containing heterocyclic mole- cules. [19] Although it is likely that the presence of aromatic substituents is undesirable for the probe reactions,b ecause benzene can capture muonium, [17] Westsp revious report on asterically encumbered silylene,bearing the 2,6-diisopropylphenyl groups,w hich provided the corresponding radical by regioselective muonium addition to the silicon center, [20] stimulated attempts at muon spin rotation and resonance (mSR) [16,21] studies of 1,3-diphosphacyclobutane-2,4-diyls bearing aromatic substituents.…”