Versatile phosphite ligands based on silsesquioxane backbones

J.I. Vlugt, van der, J. Ackerstaff, T W Dijkstra, A.M. Mills, H. Kooijman, A.L. Spek, A. Meetsma, H.C.L. Abbenhuis, D. Vogt

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Silsesquioxanes are employed as ligand backbones for the synthesis of novel phosphite compds. with 3,3'-5,5'-tetrakis(tert-butyl)-2,2'-dioxa-1,1'-biphenyl substituents. Both mono- and bidentate phosphites are prepd. in good yields. Two types of silsesquioxanes are employed as starting materials. The monophosphinite 1 and the monophosphite 2 are prepd. from the thallium silsesquioxide derived from a completely condensed silsesquioxane framework (c-C5H9)7Si7O12SiOTl. The diphosphite 3 is synthesized starting with the incompletely condensed monosilylated disilanol (c-C5H9)7Si7O9(OSiMePh2)(OH)2. For monophosphite 2, the corresponding trans-[PtCl2(2)] complex 4 is characterized by NMR spectroscopy as well as by X-ray crystallog., as the first example of a completely condensed oxo-functionalized silsesquioxane framework. The coordination of the bidentate ligand 3 towards Pd, Mo and Rh is studied, both by NMR spectroscopy as well as by X-ray crystallog. Various modes of coordination are shown to be possible. The mol. structures for the complexes trans-[PdCl2(3)] (5), cis-[Mo(CO)4(3)] (6) and the dinuclear complex [{Rh(m-Cl)(CO)}2(k2-3)] (7) have been detd. In the rhodium-catalyzed hydroformylation of 1-octene high activities, with turnover frequencies of up to 6800 h-1, are obtained with these new nanosized phosphorus ligands
Original languageEnglish
Pages (from-to)399-412
JournalAdvanced Synthesis & Catalysis
Issue number4
Publication statusPublished - 2004


Cite this

Vlugt, van der, J. I., Ackerstaff, J., Dijkstra, T. W., Mills, A. M., Kooijman, H., Spek, A. L., ... Vogt, D. (2004). Versatile phosphite ligands based on silsesquioxane backbones. Advanced Synthesis & Catalysis, 346(4), 399-412.