Reactivity of Pt(0) bromosilylene complexes towards ethylene

The base-free carbazolyl bromosilylene RSiBr (R = 1,8-bis(3,5-di-tert-butyl-phenyl)-3,6-di-tert-butyl-carbazolyl) reacts with (η$^2$-C$_2$H$_4$)Pt(PPh$_3$)$_2$ and Pt(PCy$_3$)$_2$ to form platinasilacyclobutane R(Br)Si(C$_2$H$_4$)Pt(PPh$_3$)$_2$ (1) and silylene platinum complex R(Br)SiPt(PCy$_3$)$_2$ (2), respectively. When silylene complex 2 is treated with C$_2$H$_4$, the six-membered metallasilacycle R(Br)Si(C$_2$H$_4$)$_2$Pt(PCy$_3$)$_2$ (3) is obtained. All compounds are characterised by XRD and multinuclear NMR spectroscopy.