Gallium Methylene Ga8(CH2)12 on Mesoporous Silica

Abstract

Gallium methylene Ga8(CH2)12 was grafted onto large‐pore mesoporous silica SBA‐15500 and mesoporous silica MCM‐41500 with smaller mesopores, each thermally pretreated at 500 °C. For comparability reasons, trimethylgallium was employed as a grafting reagent. The hybrid materials Ga8(CH2)12@SBA‐15500, GaMe3@SBA‐15500, Ga8(CH2)12@MCM‐41500 and GaMe3@MCM‐41500 were characterized by ICP‐OES, N2 physisorption, elemental analysis, solid‐state 1H/13C/29Si NMR spectroscopy and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. To gain further insight into potential surface species, the molecular compound Ga8(CH2)12 was treated with excess (eight equivalents) of HOSi(OtBu)3, which gave the dimeric species [GaMe2{OSi(OtBu)3}]2, being isolable also from the reaction of GaMe3 with one equivalent of silanol. The hybrid materials revealed high metal contents and surface species with intact Ga–CH2–Ga linkages as proposed by NMR spectroscopy and their reactivity toward benzophenone.