Obeid NM, Klemmer L, Maus D, Zimmer M, Jeck J, Bejan I, White AJP, Huch V, Jung G, Scheschkewitz D. (Oligo)aromatic species with one or two conjugated Si[double bond, length as m-dash]Si bonds: near-IR emission of anthracenyl-bridged tetrasiladiene.
Dalton Trans 2018;
46:8839-8848. [PMID:
28387780 DOI:
10.1039/c7dt00397h]
[Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A series of aryl disilenes Tip2Si[double bond, length as m-dash]Si(Tip)Ar (2a-c) and para-arylene bridged tetrasiladienes, Tip2Si[double bond, length as m-dash]Si(Tip)-LU-Si(Tip)[double bond, length as m-dash]SiTip2 (3a-d) are synthesized by the transfer of the Tip2Si[double bond, length as m-dash]SiTip unit to aryl halides and dihalides by nucleophilic disilenides Tip2Si[double bond, length as m-dash]SiTipLi (Tip = 2,4,6-iPr3C6H2, Ar = aryl substituent, LU = para-arylene linking unit). The scope of the nucleophilic Si[double bond, length as m-dash]Si transfer reaction is demonstrated to also include substrates of considerable steric bulk such as mesityl or duryl halides Ar-X (Ar = Mes = 2,4,6-Me3C6H2; Ar = Dur = 2,3,5,6-Me4C6H, X = Br or I). Bridged tetrasiladienes Tip2Si[double bond, length as m-dash]Si(Tip)-LU-Si(Tip)[double bond, length as m-dash]SiTip2 with more extended linking units surprisingly exhibit fluorescence at room temperature, albeit weak. DFT calculations suggest that partial charge transfer character of the excited state is a possible explanation.
Collapse