Silylenes stable dicoordinate

Thermally stable dicoordinate silicon compounds have been known since 1986, when Jutzi and coworkers reported the remarkable 7r-complex, (MesCs Si360. The chemistry of this compound, developed over the past decade, makes a fascinating story361. Other compounds of dicoordinate silicon include the four-coordinate phosphorous compound, Si[(Me2P)2C(SiMe3)]2362. These compounds, with coordination numbers at silicon greater than 2, behave rather differently from silylenes in their reactions and will not be covered here. 

More commonly the disilene is also unstable and undergoes further dimerization or polymerization below room temperature. Attempts to stabilize silylenes sterically have met with only limited success. The best example is the silylene 1, which could be observed in solution but not isolated [17]. For the heavier elements of group 14, dicoordinate compounds are well-known, and in 1991, a stable dicoordinate carbene 2 was reported [18] by Arduengo. The latter compound provided the key to the synthesis of a stable silylene [7]. 

A major advance in silylene chemistry over the past five years has been the synthesis of persistent dicoordinate silicon compounds stable silylenes . 

Two thermally stable and dicoordinate silylenes have to date been reported lii[N(tBu)CHCHN/Bu] [1] and X-ray analysis authenticated s ii CH2tBu)2C6H4-l,2] 1 [2]. The chemistry of Si[N(tBu)CHCHl Bu] was explored in the context of its reactions with [Ni(CO)4], MciSINb, PhsCNs or B(C6Fs)3 [3]. A wider range of reactions has been studied for 1. Thus, oxidative addition reactions of 1 with X-Y or E yielded the silicon compounds [1(X)Y] (X-Y = Me-I or EtO-H) or... 

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