Cage rearrangement

Figure 11 Base-catalyzed cage rearrangement of alkyl silsesquioxanes.

As previously seen for other POSS derivatives, compounds Ts[(CH2)3X]8 (X = Cl, Br, 1, or SCN) react in the presence of base to give Tio and T12 homologs by cage rearrangement. The iodide, T8[(CH2)3l]8, reacts with 2-methyl-2-oxazoline to give a precursor that can be used for polymer blending (Figure 45). ... 

Several T12R12 species have been obtained by cage rearrangement as seen for the preparation of TjoRio compounds. Here, the range of T12 compounds obtained is smaller than for the Tjo analogs and all have D2d symmetry as shown by the two... 

For example, irradiation of either 2-naphthyl acetate (2-NA) or 2-naphthyl myristate (2-NM) in the rubbery state of a low density polyethylene (LDPE) or a high density polyethylene (HDPE) yields a variety of in-cage rearrangement products and 2-naphthol (2-NOL), a cage-escape product (Table 13.2). Both LDPE and HDPE consist of amorphous and crystalline regions LDPE has a larger volume... 

The cage rearrangements required knowledge of the thermodynamic stability of hydrocarbons. Experimental data were not available. This is why I became interested in computations in the mid-1960s. The computers... 

As shown in Scheme 2, anions of type 2 (formed by the deprotonation of the zwitterionic tricarbollides 7-R R HN-n/Wo-7,8,9-C3BgHio 2 with NeiH) undergo, instead of expected complexation, an interesting metal-promoted cage rearrangement upon reactions with anhydrous NiCb (a similar reaction proceeds also with FeL, FeCL, C0CI2, and NiCp2)... 

Cage rearrangement is an established procedure to prepare polyhedral silsesquioxanes (RSiOi.5)n with n > 8. " Normally, the portion of compounds with n > 12 is very small and difficult to characterize. As shown previously, SEC in combination with MALDI-TOF-MS is a very powerful tool to identify... 

In the following, a new example of the cage rearrangement is demonstrated. In Figure 31.7a, the SEC elution curve of the sample containing HepgSigOn (Hep = n-heptyl) is shown. 

Studies on the halogenation of I-SB9H9 suggest that cage rearrangement plays a role in the ultimate stereochemistry of the products. ... 

Synthesis of Homo- and Mixed-Functionalized Octa-, Deca- and Dodeca-Silsesquioxanes by Cage Rearrangement and their Characterization... 

However, the greatest number of silsesquioxanes are homo-functionalized, which means that all residues R at the silsesquioxane cage R (SiOi.5) are of the same type. In mixed-functionalized silsesquioxanes R,tR y(SiOi.5) (with jc + y = ), R and R are different. Compared to the number of homo-functionalized silsesquioxanes mixed-functionalized silsesquioxanes are rather rare. With the exception of (C6H5)H9(SiO. 5)io [3] all other mixed-functionalized silsesquioxanes show the octa-cage size. Two new mixed-functionalized silsesquioxanes of the deca-cage type described in this article can also be synthesized by cage rearrangement. 

Cage rearrangement of silsesquioxanes is an interesting method of synthesizing homo-functionalized silsesquioxanes (see Eq. 1.). 

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