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Synthesis and Characterization of a Singlet Delocalized 2,4‐Diimino‐1,3‐disilacyclobutanediyl and a Silylenylsilaimine
Author(s) -
Zhang ShuHua,
Xi HongWei,
Lim Kok Hwa,
Meng Qingyong,
Huang MingBao,
So CheukWai
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201103351
Subject(s) - delocalized electron , singlet state , substituent , chemistry , toluene , stereochemistry , ring (chemistry) , characterization (materials science) , crystallography , materials science , physics , nanotechnology , organic chemistry , atomic physics , excited state
The synthesis and characterization of a singlet delocalized 2,4‐diimino‐1,3‐disilacyclobutanediyl, [LSi(μ‐CNAr) 2 SiL] ( 2 , L: PhC(N t Bu) 2 , Ar: 2,6‐ i Pr 2 C 6 H 3 ), and a silylenylsilaimine, [LSi(NAr)SiL] ( 3 ), are described. The reaction of three equivalents of the disilylene [LSiSiL] ( 1 ) with two equivalents of ArNCNAr in toluene at room temperature for 12 h afforded [LSi(μ‐CNAr) 2 SiL] ( 2 ) and [LSi(NAr)SiL] ( 3 ) in a ratio of 1:2. Compounds 2 and 3 have been characterized by NMR spectroscopy and X‐ray crystallography. Compound 2 was also investigated by theoretical studies. The results show that compound 2 possesses singlet biradicaloid character with an extensive electronic delocalization throughout the Si 2 C 2 four‐membered ring and exocyclic CN bonds. Compound 3 is the first example of a silylenylsilaimine, which contains a low‐valent silicon center and a silaimine substituent. A mechanism for the formation of 2 and 3 is also proposed.