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Distinctly different reactivity of bis(silylenyl)-versus phosphanyl-silylenyl-substituted o-dicarborane towards O2, N2O and CO2

Xiong, Yun; Yao, Shenglai; Ruzicka, Ales; Drieß, Matthias

FG Metallorganische Chemie und Anorganische Materialien

In stark contrast to the reactivity of the bis-silylenyl dicarborane CB–Si2 (1) [CB = ortho-C,C′-C2B10H10, Si = PhC(tBuN)2Si] towards O2, N2O, and CO2, yielding the same dioxygenation product CB–Si2O2 (2) with a four-membered 1,3,2,4-disiladioxetane ring, the activation of the latter small molecules with the phosphanyl-silylenyl-functionalised CB–SiP (3) {P[double bond, length as m-dash]P[N(tBu)CH2]2} affords with O2 the CB–Si([double bond, length as m-dash]O)P([double bond, length as m-dash]O) silanone-phosphine oxide (4), with N2O the CB–Si([double bond, length as m-dash]O)P silanone-phosphine (5), and with CO2 the CB–Si(O2C[double bond, length as m-dash]O)P silicon carbonate-phosphine (6) and CB–C([double bond, length as m-dash]O)OSiOP ester (7), respectively.