Higher generations of poly(propylene imine) dendrimers functionalized with aliphatic chains form large micrometer-sized spherical objects in aqueous solution below pH 8. These spheres are giant vesicles with a multilaminar onion-like structure. The size distribution and the structure of the vesicles depend on the pH of the solution and the endgroups at the periphery of the dendrimer. The vesicles containing azobenzene units (2 and 3) fluoresce with a maximum at λ max ) 600 nm. This emission can be attributed to the dense and ordered arrangement of the azobenzene chromophores in the bilayer structure. Laser irradiation of a small area of giant vesicles of 2 or 3 with 1064 and/or 420 nm light leads to changes in the morphology of the vesicles. Infrared light induces a rearrangement, whereas the azobenzene units isomerize under the influence of 420 nm light. Both irradiations lead to a change in refractive index in the illuminated area. Irradiation using 420 nm light is accompanied by an increase in the emission intensity. In aqueous solutions at pH 1, the increase in fluorescence intensity is concurrent with a blue shift of the emission maximum to 540 nm. This blue shift is not observed when the experiment is performed in Milli Q water (pH 5.5). The enhanced fluorescence can be attributed to reorganization of the chromophores within the giant vesicle. The increase in emission proves that the giant vesicle is a kinetically formed system that reaches a thermodynamically more relaxed state after light-induced isomerization.

Ligand effects in the palladium catalyzed reductive carbonylation of nitrobenzene Wehman, P.; Dol, G.C.; Moorman, E.R.; Kamer, P.C.J.; van Leeuwen, P.W.N.M.; Fraanje, J.; Goubitz, K. Published in: Organometallics DOI:10.1021/om00024a031Link to publication Citation for published version (APA):Wehman, P., Dol, G. C., Moorman, E. R., Kamer, P. C. J., van Leeuwen, P. W. N. M., Fraanje, J., & Goubitz, K. (1994). Ligand effects in the palladium catalyzed reductive carbonylation of nitrobenzene. Organometallics, 13, 4856-4869. DOI: 10.1021/om00024a031 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Reductive carbonylation of nitrobenzene in methanol in the presence of a palladium catalyst yields mainly methyl N-phenylcarbamate. Diphenylurea is formed as the most important byproduct. A series of 4,4'-disubstituted-2,2'-bipyridyl ligands (R = F3C, C1, H, Me, MeO, and Me2N) has been used to study the influence of the donating capacity of the ligand on the catalytic activity and selectivity. By way of two different types of complexes, Pd(1igand)z-(OTo2 and Pd(ligand)Cl(OTf), the influence of the anions in the catalytic system has also been studied. Electron-withdrawing substituents on the bipyridyl ligand turned out to completely deactivate the catalyst, while only small differences were found between the ligands with electron-donating substituents. Chloride anions showed a n inhibiting effect. The presence of water reduced the selectivity toward carbamate. At prolonged reaction times the urea side product was catalytically converted into the desired carbamate. Under more severe conditions carbamates, urea side products, and anilines were found with methoxy substituents on their phenyl rings. X-ray structures were elucidated for Pd(bpy)a(OTf)z and Pd(Me-bpy)z(OTf)z. The Pd(b~y)~(OTfl:! crystals were monoclinic, space group P21/n, a =

Suzuki and Stille cross‐coupling reactions were utilized in the synthesis of 5‐substituted 1,3‐dimethoxybenzene and 5‐substituted resorcinol derivatives. The substituted resorcinol derivatives were obtained in only three steps from inexpensive reagents. 1,3‐Dimethoxybenzoic acid and 1‐chloro‐3,5‐dimethoxybenzene were transformed into 1‐iodo‐, 1‐bromo‐, 1‐trimethyltin‐3,5‐dimethoxybenzene and 3,5‐dimethoxyphenyl boronic acid. 5‐Allyl‐1,3‐dimethoxybenzene and 3,5‐dimethoxybiphenyl derivatives were obtained via cross coupling reactions under mild conditions. HI, BBr3 and AlI3 were used to demethylate these dimethoxybenzenes into their resorcinol derivatives.

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