Organic cores

The core of organic composite latex particles can be varied along with the desired properties. The most important parameters of the polymer in the core are the Tg, the molar mass, the crosslink density, and the type of (co)polymer. Composite latex particles used for impact modification consist of a rubbery core and a glassy shell that is miscible or can react with the matrix. Examples of such types of polymers are the very important acrylonitrile-butadiene-styrene (ABS) composite polymer and also the methyl methacrylate-butadiene-styrene transparent composite polymer for the impact modification PVC. For coating applications the latex particles often consist 

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There are, of course, metal-containing dendrimers that belong to more than one of the above-mentioned categories. Examples are the heptametallic dendrimer made of a central Fe(Cp)(C6Me6)+ core and coated with 6 ferrocene moieties [ 12], and the heterometallic dendrimers made of an organic core, containing up to 6 Pt(IV)-based organometallic species in the branches, and coated with up to 12 ferrocene units [13]. 

Considerable research effort was focused on systems of colloidal gold of which a broad variety of synthetic procedures were reported [140 b, fj. While native colloidal gold solutions are only stable for a restricted time, Brust et al. [141] were able to overcome this problem by developing a simple method for the in situ preparation of alkyl thiol-stabihzed gold nanoparticles. This synthetic route yields air-stable and easy to handle passivated nanoparticles of moderate polydispersity, and is now commonly employed for the preparation of inorganic-organic core-shell composites. Such composites are used as catalytic systems with principally two different functions of the protective 3D-SAM layer. Either the metal nanoparticle core can be used as the catalytically active center and the thiol layer is only used to stabihze the system [142], or the 3D-SAM is used as a Hnker system to chemically attach further catalytic functions [143]. 

Molecular structures of two centrosymmetric inverse crown molecules containing organic cores ... 

Assuming the pleated sheet-like motif and the ribbon-like motif as reference H-bonded core structures, a further increase in the steric demand of the residues, as for example the presence of aromatic rings as substituents on the diol or diamine moiety, or the absence of the required trans configuration, lead to a loss of efficiency in the recognition process with formation of incomplete ribbon-like or staircase-like structures. In the latter cases, competition experiments show that matched complexes with the pleated sheet-motif or with the ribbon-like motif of the core crystallize more easily than those characterized by incomplete or low organized core structures. Thus, when the complex 29 38 was melted with 1 equiv. of (i ,i )-tra x-l,2-cyclohexanediol (31) and the mixture was crystallized from benzene, again 29 31 was obtained as the only crystalline product (Scheme 22) [60]. 

The results observed for 13 and 14 clearly showed the strong influence of the orientation of the ester linking function on the mesomorphic properties. An explanation of this influence was attempted from stereoelectronic and structural considerations (Scheme 9-1). In A, the organic unit used to prepare 13, electron delocalization occurs from the O-atom of the alkoxy chain to the ester function. Thus, mesomerism takes place in the external part of the organic fragment. However, in B, from which series 14 was built up, electron delocalization appears in the interior of the organic core, and in the opposite direction. Consequently, the O-atom of the ether group is more polar in A than in B. Furthermore, examination of CPK... 

LCs typically have an aromatic organic core with ionic groups lining the periphery, giving them a disk- or plank-like shape (e.g., ionic organic dye molecules). They are technically classified as LLCs because they can self-assemble into ordered phases in the presence of water. However, unlike traditional amphiphiles, lyotropic chromonic LCs are rigid rather than flexible, and their hydrophobic components are based on aromatic units rather than aliphatic chains. Unlike traditional amphiphilic LCs, they self-organize in so-... 

Scheme 2.71 shows the preparation of an octametallic star-shaped molecule containing cyclopentadienyliron arene complexes at the peripheries. The reaction of the organic core, 269, with the organometallic complex, 270, gave the organometallic star-shaped molecule, 271. A previously reported synthesis of 271 occurred via deprotonation of a permethylated iron complex. Astruc et al. have also reported silicon-containing star-shaped molecules, 272.312... 

Noncovalent polymers are defined here as molecular assemblies with a high degree of polymerization (PN > 100) and well-defined molecular arrangements in solution as well as in the dry state. We also include membrane-coated colloidal metal or silicate particles with rigid nanometer gaps. The spherical or planar carrier is needed to fixate the membrane structures, which are not distinguishable by substances in the bulk water or solvent phase from clefts in the surfaces or polymers with an organic core. 

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