Polynitrile

With this method new dendrimers were prepared in the following years by Denkewalter et al. [22], Tomalia et al. [23], Newkome et al. [24], and ourselves [25]. Following a reaction pathway similar to the one used in 1978, Meijer et al. successfully synthesized a polynitrile dendrimer 14 up to the fifth generation on a large scale [26] (Fig. 8). 

It is clear that a complex hydrocarbon polymer chemistry must exist in the atmosphere of Titan involving polyyne species, polynitrile species and mixtures of the two, and additional routes to polyaromatic hydrocarbon formation. This presents a significant problem for the gas chromatography/mass spectrometry instruments on the Huygens probe. There should be hydrocarbon fragments, producing perhaps... 

As most of the work with this type of salts was essentially motivated by the results obtained with the salts based on decamethylmetalocenium cations and polynitrile planar radical anions, the use of different metallocenium derivatives was limited to a small number of compounds. Among these only [Fe (C5Me4SCMe3)2][M(mnt)2], M = Ni and Pt, present crystal structures based on mixed linear chain motives. 

Aqueous polynitrile oxide curing compositions, with good storage stability, have been patented (525). The compositions comprise aqueous dispersions containing nitrile oxides and are useful for coating systems that are cured at room temperature without the release of byproducts. Latexes are cured by mixing a polymer latex with a stable polynitrile oxide, for example, 2,4,6-triethylbenzene -1,3-dicarbonitrile oxide, and removing water from the mixture. 

Foam compositions, including a latex and a polynitrile oxide such as 2,4,6-triethylbenzene-l,3-dicarbonitrile oxide, or a latex and an epoxy silane, or a latex and a mixture of the two crosslinkers have been prepared (526). The compositions may also contain additional components, including fillers, surfactants, cell detackifiers, froth stabilizers, froth boosters, viscosity reducers, and compounds to improve resilience, and antioxidants. The compositions are particularly useful in the manufacture of flooring, wall covering, shoe lining and nonwoven materials. 

As briefly alluded to, there are different classes of redox-active ligands in addition to the above mentioned ones. For example, we have seen in Chapter 5, Section 8, that azo-groups (in particular, 2-(phenylazo)pyr-imidine) are able to undergo two separate one-electron reduction processes. Conjugated polynitriles (mnt, tcne, tcnq) also constitute an important class of redox-active molecules and the electrochemical behaviour of their metal complexes has been reviewed.107 The same holds as far as alkyldithiocarbamates (Rdtc) and their metal complexes are concerned,108 or nitrosyl complexes in their possible NO+[NO fNO redox sequence.109 Thus, we would like to conclude the present Chapter by discussing a few less known redox non-innocent ligands. 

This problem will be considered on the basis of charge-transfer coordination of organic polynitriles to substituted ferrocenes. The practical significance of the charge-transfer coordinative species (salts) is their ferromagnetic behavior (see Section 8.5). The salts contain the cation-radical and anion-radical counterparts. Peculiarities in electronic structures of the cation-radical parts within the salts are topics of our interest. 

Fig. 16. Monsanto undivided cell EHD process flow sheet where AN is acrylonitrile ADN adinonitrile and PN polynitrile (41).

Polynitriles have been prepared from QH —CO and C2H4 -C3H6 -CO copolymers by the following procedure, Eq. (23)70). Analysis indicated the presence... 

Womer C, Miilhaupt R (1993) Polynitrile-functional and polyamine-functional poly(trimethy-lene imine) dendrimers. Angew Chem Int Ed Engl 32 1306-1308... 

In all the discrete structures described above, the axial sites are either open or bound to a weak donor ligand. A number of extended structures have been made by reacting [ cri-Rh2(DAniF)2 (02CCH2C02)]2 and [ cri-Rh2(DAniF)2 (02CC02)]4 with the polypyridine or polynitrile ligands. The resulting structures include one, two-, and three-dimensional molecular tubes that are described in detail elsewhere. ... 

Another important feature is the structural uniformity of polyPc. Ortho di- or tetranit-riles may be converted to poly-isoindolenines (polynitriles) as 91) and polytriazines as (92) Generally, polymers prepared from TCB may contain the structure elements (86), 91), 92) (Eq. 42). 

T-electron delocalisation in the Pc-layers. On the other side a reaction between TCB and Cu(II)-acetylacetonate formed a polymer showing broad absorptions in the IR-spectra (Fig. 6, C). Also the UVA IS-spectra have an very intensive ateorption beginning at 500 nm and increasing with shorter wave length which is typical for polynitrile like (97) (Fig. 7, C). Pc-units are identified only at small absorptions at 735 nm. There is no indication of triazine structure elements (92) having absorption lines at 1610,1540,1450 and 1370 cm". ... 

The conversion of TCB to metal free polymers needs some urea as initiator . The obtained polymers were divided into acetone soluble, DMF soluble, DMF insoluble and cone. H2SO4 insoluble fractions. The highest yield of products soluble in organic solvente (50% acetone or 75-80% DMF soluble) were obtain with 1,5-3 mole % urea at 573 K in 10 h. DMF insoluble fractions resulted at 573 K in 40 h with an urea concentration > 20 mole %. In every case elementary analysis is in good agreement with expected values. But the IR-spectra show some C=0 absorption (saponification) and broad background absorption (possible polynitrile 91) formation). An expected absorption typical for metal free Pc is present at 1000 cm. ... 

Anti-tumor activity of some polynitrile derivatives including derivatives of 2-pyrroline, pyrrole, 2,7-dioxabicyclo[3,2,l]octane, pyrido[3,4 3,4]pyrrolo[l,2-(2]-1,3,5-triazine, pyrrolo[3,4-c]pyridine, and 1,2,3,4-tetrahydropyridine 00KFZ(4)11. 

Dendrimers can be reacted with a variety of compounds to further functionalize them to give them unique characteristics. For example, amine-terminated dendrimer can be reacted with imsaturated nitriles to give a polynitrile dendrimer. In another case the polyamine dendrimer can be reacted with jS-unsat-urated amides to give amide-terminated dendrimer. A whole host of possibilities can be visualized based on the reactivity of the amino group [43]. 

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