The synthesis of the novel diorganosilanes {4-t-Bu-2,6-[P(O)(OR)2]2C6H2}Si(H)2Ph (5, R = Et; 6, R = i-Pr) is reported. Compound 5 reacts with lithium chloride in the presence of air moisture to give the complex 5·LiCl·2H2O (5a). The crystal and molecular structures of the diorganosilane 6 and complex 5a were determined by single-crystal X-ray diffraction analysis. The latter compound shows unprecedented (5·Li+)6 hexamers which are further linked by water to give a two-dimensional coordination polymer. The reaction of compound 6 with [Ph3C]+PF6 - provided in situ a mixture of the triorganosiliconium salts {4-t-Bu-2,6-[P(O)(O-i-Pr)2]2C6H2}Si(X)Ph+PF6 - (7, X = H; 8, X = F), whereas reaction with CCl4 gave a mixture of the benzoxasilaphospholes [1(P),3(Si)-P(O)(O-i-Pr)OSi(X)Ph-6-t-Bu-4-P(O)(O-i-Pr)2]C6H2 (9, X = H; 10, X = Cl).

Dedicated to Professor Michael Veith on the occasion of his 65th birthday.

The syntheses and structures of the [4 + 1]-coordinated triorganosilane {4-t-Bu-2,6-[P(O)(O-i-Pr)2]2-C6H2}SiPh2H (5) and of the intramolecularly coordinated triorganosiliconium hexafluorophosphate {4-t-Bu-2,6-[P(O)(O-i-Pr)2]2C6H2}SiPh2 +PF6 - (6) are reported. In the solid state, compound 5 adopts a rotameric form that differs from those found for {4-t-Bu-2,6-[P(O)(OEt)2]2-C6H2}SiPh2R (R = Ph, H).