TY - JOUR
T1 - Conformationally Switchable Silylone
T2 - Electron Redistribution Accompanied by Ligand Reorientation around a Monatomic Silicon
AU - Koike, Taichi
AU - Nukazawa, Takumi
AU - Iwamoto, Takeaki
N1 - Funding Information:
This work was supported by the JSPS KAKENHI (grant JP20J21205 to T. K.; JP15K13634 to T. I.) and the Mitsubishi Foundation research grant in the natural sciences (201910006 to T.I.). The authors thank Prof. Shinya Takaishi and Mr. Shohei Koyama (Tohoku University) for helpful advice in the measurement of the solid-state UV–vis spectra.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/9/8
Y1 - 2021/9/8
N2 - Complexes that could be switched between two electronic states by external stimuli have attracted much attention for their potential application in molecular devices. However, a realization of such a phenomenon with low-valent main-group element-centered complexes remains challenging. Herein, we report the synthesis of cyclic (alkyl)(amino)silylene (CAASi)-ligated monatomic silicon(0) complexes (silylones). The bis(CAASi)-ligated silylone adopts a π-localized ylidene structure (greenish-black color) in the solid state and a π-delocalized ylidene structure (dark-purple color) in solution that could be reversibly switched upon phase transfer (ylidene [L: →:Si = L ↔ L = Si: ←:L]). The observed remarkable difference in the physical properties of the two isomers is attributed to the balanced steric demand and redox noninnocent character of the CAASi ligand which are altered by the orientation of the two terminal ligands with respect to the Si-Si-Si plane: twisted structure (π-localized ylidene) and planar structure (π-delocalized ylidene). Conversely, the CAASi/CDASi-ligated heteroleptic silylone (CDASi = cyclic dialkylsilylene) only exhibited the twisted π-localized ylidene structure regardless of the phase. The synthesized silylones also proved themselves as monatomic silicon surrogates. Thermolysis of the silylones in the presence of an ethane-1,2-diimine afforded the corresponding diaminosilylenes. Analyses of the products suggested a stepwise mechanism that proceeds via a disilavinylidene intermediate.
AB - Complexes that could be switched between two electronic states by external stimuli have attracted much attention for their potential application in molecular devices. However, a realization of such a phenomenon with low-valent main-group element-centered complexes remains challenging. Herein, we report the synthesis of cyclic (alkyl)(amino)silylene (CAASi)-ligated monatomic silicon(0) complexes (silylones). The bis(CAASi)-ligated silylone adopts a π-localized ylidene structure (greenish-black color) in the solid state and a π-delocalized ylidene structure (dark-purple color) in solution that could be reversibly switched upon phase transfer (ylidene [L: →:Si = L ↔ L = Si: ←:L]). The observed remarkable difference in the physical properties of the two isomers is attributed to the balanced steric demand and redox noninnocent character of the CAASi ligand which are altered by the orientation of the two terminal ligands with respect to the Si-Si-Si plane: twisted structure (π-localized ylidene) and planar structure (π-delocalized ylidene). Conversely, the CAASi/CDASi-ligated heteroleptic silylone (CDASi = cyclic dialkylsilylene) only exhibited the twisted π-localized ylidene structure regardless of the phase. The synthesized silylones also proved themselves as monatomic silicon surrogates. Thermolysis of the silylones in the presence of an ethane-1,2-diimine afforded the corresponding diaminosilylenes. Analyses of the products suggested a stepwise mechanism that proceeds via a disilavinylidene intermediate.
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U2 - 10.1021/jacs.1c06654
DO - 10.1021/jacs.1c06654
M3 - Article
C2 - 34448394
AN - SCOPUS:85114463547
VL - 143
SP - 14332
EP - 14341
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 35
ER -