Poly hydrogen donor

It might be pertinent to consider the basis of the extremely facile isomerization in anhydrous HF or pyridinium poly(hydrogen fluoride). HF is an extremely strong proton donor, but it is also a potent fluorinating agent. It is highly probable that the postulated cationic intermediates in these isomerizations are fluori-nated and serve as reactive intermediates in the same way as the fructofuranosyl... 

The above finding led to another interesting conclusion that a minimum chain length is essential for PEG to form a stable complex with a-CD. The chain length selectivity implies that some cooperative action is involved in this complex formation as is well known in the complex formation of PEG with hydrogen-donor polymers such as poly(acrylic acid). 

Coleman and Royer employed Pd-poly(ethyleneimine) ghost as an effective catalyst for the hydrogen transfer hydrogenolysis of Z group in peptide synthesis, using formic acid as a hydrogen donor.81... 

UV irradiation of poly(4-vinylbenzophenone) [poly(VBP)] in benzene solution, and in the presence of isopropanol as hydrogen donor, gives rise to a more complex picture [12,13]. Indeed, intra- and inter-molecular coupling reactions by the side-chain benzophenone ketyl radicals (K ) markedly change the macro-molecular morphology with the occurrence of cyclic and network structures as well as chain scission processes (Scheme 5). 

Finally, as the above experiments have been performed in benzene, a very weak hydrogen donor, they clearly indicate that in poly(ABP) the hydrogen abstraction occurs through an intramolecular mechanism. 

Using poly(methylhydrosiloxane) (PMHS) as the hydrogen donor, aryl and benzyl halides can be carbonylated to aldehydes in the presence of [Pd(PPh3>4] under mild conditions (3 bar, 80 °C). The reaction only works for iodides 4-bromophenyl iodide, for example, is converted to 4-bromobenzaldehyde in 95% yield (equation 6). 

Encinas. S. Simpson, N.R.M. Andrews, P. Ward. M.D. White, C.M. Armaroli, N. Barigelletti, F. Houlton. A. Photoinduced energy transfer within hydrogen-bonded multi-component assemblies based on a ruthenium-poly-pyridyl donor and an osmium-polypyridyl or ferrocenyl acceptor. New J. Chem. 2000, 24 (12). 987-991. 

TAS 07a] Tasdelen M.A., Demirel A.L., Yagci Y., Poly(propylene imine) dendrimers as hydrogen donor in Type II photoinitiated free radical polymerization , European Polymer Journal, vol. 43, pp. 4423-4430, 2007. 

Gam-Derouich, S., A. Lamouri, C. Redeuilh, R Decorse, F. Maurel, B. Carbonnier, S. Beyazit, G. Yilmaz, Y. Yagd, and M. M. Chehimi. Diazonium salt-derived 4-(dimethyl-amino)phenyl groups as hydrogen donors in surface-confined radical photopolymerization for bioactive poly(2-hydroxyethyl methacrylate) grafts. Langmuir 2012 8035-8045. 

The poly(benzophenone) diradical (5.27) easily abstracts hydrogen from hydrogen-donor molecules (RH) or from a polymer molecule (PH) giving the poly(benzophenone) ketyl radical (5.2S) ... 

Special types of hydrogen donors include phenols and aromatic amines. Notably, aromatic amines are also known as accelerators in peroxide curing of unsaturated poly(ester)s resins. The mechanism of the decomposition of peroxide radicals by aromatic amines is shown in Figure 19.3. 

Poly(methylhydrosiloxane) (PMHS) as hydrogen donor in the presence of Pd(PPhs)4 have been successfully employed to formylate aryl and benzyl halides at low carbon monoxide pressure (Eq 1.35). ° ... 

Silicon is used in many fonns, from high-purity tliin films to bulk material, which may be crystalline, multi- or poly crystalline and amorjDhous (usually hydrogenated). Silicon is the material discussed tire most in tliis article. Substitutional B and P are tire most common (of many) shallow acceptors and donors, respectively. 

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