Organosilanetriols: model compounds and potential precursors for metal-containing silicate assemblies

Abstract

The chemistry of silanols and related amino‐­silanes is a topic of current interest in view of their possible applications as building blocks in materials science. In particular, discrete silanetriols and triaminosilanes are useful synthons for the generation of three‐dimensional metallasiloxanes. Research work in our laboratory in this area is centered around the synthesis of stable silanetriols and studies of their reactivity toward various metal precursors. Starting from a series of stable N‐bonded silanetriols and triaminosilanes, we have been able to synthesize a range­of metallasiloxanes and iminosilicates showing novel structural features. Elements such as aluminum, gallium, indium, titanium, zirconium, tantalum, tin and rhenium have been incorporated in these heterosiloxane frameworks. Both the metallasiloxanes and iminosilicates have been extensively characterized by means of IR and NMR spectroscopy and by single‐crystal X‐ray diffraction studies in representative cases. A (cobalt carbonyl cluster)‐anchored aluminosiloxane is an efficient catalyst for hydroformylation reactions of olefins. Many of these metallasiloxanes and iminosilicates contain hydrolyzable functionalities such as M–C, M–OR and Si–N bonds, providing a possibility of using these compounds as starting materials for the preparation of supramolecular cage structures and synthetic zeolites under mild conditions. Copyright © 1999 John Wiley & Sons, Ltd.

Organic Soluble Silicophosphonate [RSi(OH){OP(O)(H)(OH)}]2O (R = (2,6-i-Pr2C6H3)NSiMe3): The First Silicophosphonate Containing Free Si−OH and P−OH Groups

“…In spite of the poor quality of the X-ray diffraction data, the bond distances and bond angles obtained for 1 are consistent with the values reported for simple silanols and phosphonic acids in the literature. , The two phosphonate moieties in the molecule adopt an approximate trans orientation on the central siloxane unit. The silicon and phosphorus atoms in the molecule are approximately tetrahedral.…”

“…Similarly, the original doublet 29 Si NMR spectrum due to the siloxide of 1 completely disappears with the appearance of two new upfield doublets at −86.0 and −88.3 ppm. These spectral changes are consistent with the formation of P−O−Al and Si−O−Al linkages, , indicating the existence of molecular SAPO species in solution. Our attempts to obtain single crystals of these species have so far not been successful.…”

New Polyhedral Zinc Siloxanes: Synthesis and X-ray Crystal Structures of Zn8Me7(dioxane)2(O3SiR)3 and [Zn7Me2(THF)5(O3SiR)4] [R = (2,6-i-Pr2C6H3)N(SiMe3)]

“…The molecular structure of 6 consists of a nearly cubic Zn 4 Si 4 O 12 unit with zinc and silicon atoms occupying alternate corners of the cube [Zn2−Si3−Zn3−Si1−Zn5−Si5−Zn6−Si7]. In this regard this framework is analogous to those found for other metallasiloxanes of the type [RSiO 3 M·S] 4 (M = Al, Ga, In; S = THF). − ,, Three of the contiguous faces of the cube are capped by zinc atoms (Zn4, Zn1, Zn7), while the other three faces are open. The presence of the capping zinc units is reminiscent of the molecular structure of the trimetallic derivative 3 (Scheme ).…”

1-Oxa-3-aza-2,4-disilacyclobutanes − Synthesis, X-ray Structures, and Reactivity

“…Our attempts to isolate the lithium derivative of 1 in the reaction of 1 and BuLi were unsuccessful, LiF elimination occurred and the 1-aza-3-oxa-2,4-disilacyclobutane 2 was obtained [Equation (4)]. …”