Encapsulation, complex hydrides

Thicker sections can be cross-linked by hydrosilylation addition. This is the same chemistry used to produce fluorosilicone monomers with the vinyl functionality present on silicon. The catalyst reaction occurs between a vinyl group and silicone hydride.66 The advantage of this system is that it does not produce volatile by-products. On the other hand, the disadvantage is that it is available only as a two-part system.67 Recently, however, one-part, platinum-catalyzed products have been developed.66 The reaction is very rapid and at room temperature it is completed in 10 to 30 minutes. It is accelerated with increasing temperature and at 150°C (302°F) it is completed within a few seconds. This makes the compounds ideal for fast automated injection molding operations.68 One-part systems use the chemical complexing of the catalyst, which is activated at elevated temperatures, or its encapsulation into an impermeable shell, which is solid at room temperature and melts at elevated temperatures68... 

Further studies on the supramolecular coordination chemistry of copper(II) focused on the synthesis of oligonuclear complexes by self-assembly with the pentadentate ligand (L3)2 with 2,6-pyridinyl-spacer [70]. To this end, H2L3 (4) was treated with calcium hydride and copper(II) acetate to give the metallocoronate [(Cac Cu2(L3)2 )(OAc)2] (5 Scheme 2). In the crystal, 5 is present as a dinuclear copper(II) coronate in which a calcium ion is encapsulated in the center two acetates act as counterions. 

When triethanolamine H3L13 (35) was reacted with sodium hydride and iron(III) chloride, the hexanuclear centrosymmetric ferric wheel [Nac Fe6(L13)6 )Cl (36) was isolated. Amidst a set of possibilities in the template-mediated self-assembly of a supramolecular system, the one combination of building blocks is realized that leads to the best receptor for the substrate [112]. Therefore, the six-membered cyclic structure 36 is exclusively selected from all the possible iron triethoxyamine oligomers, when sodium ions are present. The iron(III) complex 36 is present as an Sg-symmetric wheel, with an encapsulated sodium ion in the center and a chloride counterion. Consequently, the trianion (L13)3- acts as a tripodal, tetradentate, tetratopic ligand, which each links three iron(III) ions and one sodium ion. In the presence of cations with different ionic radii, different structures are expected. Therefore, when triethanolamine H3L13 (35) was reacted with cesium carbonate and iron(III) chloride, the octanuclear centrosymmetric ferric wheel [Csc Fe8(L13)8 ]Cl (37) was isolated (Scheme 13) [113]. 

In rhodium clusters, e.g., [Rh13(CO)14H5. ]" (n = 2 and 3), only one of the H atoms is encapsulated and 3H nmr spectra show that this atom interacts with all 13 Rh atoms (103Rh, spin V2) and is thus migrating within the cluster. Proton transfer reactions of interstitial hydrides have been studied72 and more complex hetero-nuclear species73 can be made by reactions such as... 

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