Cuproussiloxane as two self-assemblies, Cu 20 O 20 Si 10 Me 10 R 10 and Cu 24 O 24 Si 12 Me 12 R 12 , with catalytic property.

Cuproussiloxane (1) was prepared from the reaction of silanediol R(Me)Si(OH) 2 (R = N(SiMe 3 )(2,6- i Pr 2 C 6 H 3 )) and (CuMes) 4 (Mes = 2,4,6-Me 3 C 6 H 2 ). The prepared compound crystalizes into two self-assemblies: Cu 24 O 24 Si 12 Me 12 R 12 ([(CuO) 2 Si(Me)R] 12 , 1a) and Cu 20 O 20 Si 10 Me 10 R 10 ([(CuO) 2 Si(Me)R] 10 , 1b). 1a and 1b feature dodecagonal and decagonal prism X-ray structures, respectively. 1 was found to exhibit good to excellent activity for catalyzing the aerobic C-P cross-coupling reaction of terminal alkynes with H-phosphonates to form alkynylphosphonates (70-99% yields).