Frameworks interrupted

The shoulder at about 600 K is assigned to the decomposition of TPA+ located at the surface of the crystals and bound to negative centers of either surface aluminum, or oxygen, set free by a framework interruption (=Si-0 ) ... 

The only aluminophosphate known having a 20-MR system is JDF-20 (162, 163). The structure of JDF-20 viewed along the 001 direction is shown in Fig. 27. The large 20-MR elliptical channels are 14.5 x 7.9 x 6.2 A in diameter. Like Cloverite, JDF-20 is an interrupted framework that is reflected in the formula [Al5P6024H][N(Et3)H]2.2Fl20, where there is less A1 than P. This results in four P=0 and two O-H-O groups that protrude into the pore window. There are also intersecting channels defined by 10- and 8-MR structures. 

Paclitaxel is a well-established antiproliferative agent with a microtubule-targeting pharmacologic activity (37,42,43). As an anticancer agent, paclitaxel causes polymerization and stabilization of microtubules (43-45). The stabilization of microtubule dynamics by paclitaxel can interrupt many cellular processes, including cell division, migration, activation, maintenance of cytoskeletal framework, and intracellular as well as transmembrane protein transport (42,46,47). 

Feng, P. Bu, X. Stucky, G. D, Designed assemblies in open-framework materials synthesis An interrupted sodalite and an expanded sodalite. Angew. Chem., Int. Ed. Engl. 199S, 34, 1745. 

Figure 6.13 A framework of a covalently bound CjeHssSH monolayer (green blocks) is interrupted by thinner, also covalently bound template molecules (black holes), e.g. a quinone- or steroid-thiol. These template molecules serve as gates for electron transfer reactions and can be closed by signal molecules (grey blocks) which bind to those templates, e.g. carbohydrates which react with the C-17 substituent of steroid 11. The current of redox-active ions from the bulk water volume stops.

There are terminal groups in the frameworks, such as P=0, P-OH, and Al OH, which make the structures less stable than zeolites and aluminophosphate molecular sieves with (4,2) networks. These terminal groups also favor the formation of interrupted frameworks, such as cloverite and JDF-20 ... 

Solid lines represent T—O—T linkages, whereas dotted lines indicate nonconnected T—O bonds found in the interrupted frameworks. 

Cloverite is a gallophosphate molecular sieve with 20-ring channels. The Ga04 tetrahedra and PO4 tetrahedra with terminal -OH groups alternate strictly to produce an interrupted three-dimensional open framework. Figure 2.57 shows a projection of cloverite along the [100] direction with a pore opening in the shape of a four-leafed... 

Most chiral phosphates are prepared in the presence of organic amines or metal complexes with or without chiral features. By using chiral metal complexes as the SDAs, low-dimensional structures or interrupted open-framework structures tend to... 

Interrupted mordenite framework. 03 and 09 are terminal oxygens, where the framework is not fully connected. 

Since 1993, trace metal concentrations in Baltic Seawater have been analyzed on an annual basis in the framework of the HELCOM monitoring program. Beginning in 1995, it was recommended by HELCOM to perform sampling (Eig. 13.3) once a year during wintertime (February) when biological activities are limited. These measurements were interrupted by two major saltwater inflow events (Chapter 10). 

The magnitude of homoaromatic stabilization is expected to decrease with increasing interruption by methylene groups of the otherwise tr-conjugated framework in neutral molecules. However, in an ionic species there is additional incentive for charge delocalization. Two of the most widely studied bishomoaromatic cations are the 7-norbornenyl (167) and 7-norbornadienyl (168) cations. ... 

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