Platinum-disilene complexes

X-ray crystallography. The observation that our platinum-silicon 4MR can be formed from reagents with Si-Si single bonds is also consistent with the P2 h bonding description. West has prepared monoplatinum complexes of disilenes from disilenes or disilanes by three routes. One route, which is similar to the reaction depicted in Eg.4, is shown in Eg.5. The platinum disilene complexes are described by the two resonance forms drawn in Eg.5. (It is interesting to note that oligomeric silanes are obtained as by-products of Eg.5.)... 

Hashimoto H, Sekiguchi Y, Iwamoto T, Kabuto C, Kira M (2002) Synthesis and X-ray structure of a platinum -disilene complex. Organometallics 21 454... 

The Si-Si double bond of stable disilene 26 is also known to react with plati-num(0) complexes (Eq. 10) [24]. The produced complex 27 maybe regarded as disilaplatinacyclopropane or disilene-coordinated complex. An efficient preparation of the same platinum complex is also reported by the reaction of dihy-drodimesitylsilane with the platinum(O) complexes. 

Reactions of disilenes to form transition metal complexes have hardly been investigated complexes are reported only for platinum. An example is shown in Eq. (35). The Pt complex 76 was identified spectroscopically and from trapping products, but it was a minor product in the reaction and crystals could not be obtained.102... 

The chemistry of silylene-metal complexes has developed in quite another direction, however, from reactions of disilyl-metal complexes, leading to complexes of otherwise unstable disilenes such as Me2Si=SiMe2. Molybdenum and tungsten complexes have been particularly well investigated by Berry and co-workers,103 and platinum complexes have also been isolated.104 Readers interested in this field are directed to a 1992 review of silylene, silene, and disilene-metal complexes.105... 

Steric considerations may determine why different products are obtained from Eqs. 4 and S. The disubstituted silicons in the mono-platinum complex may be too hindered to bind a second platinum. Consistent with the increasing coordination number at silicon, the chemical shift in the si NMR shifts to higher field on binding a disilene (6 +45 - +95 ppm ) to one (6 = -30 - +24 ppm) or two (for trans-Tol-A, = -93.32 ppm ) platinum atoms. 

Fig. 5 Different t3 pes of silylated disilene and silene complexes of palladium and platinum...

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