An Approach Towards Functional Dendrimers Based on the Hydroboration Reaction and Spontaneous Boron-Nitrogen Bond Formation

• Published in: European Journal of Inorganic Chemistry Vol. 2005; no. 21; pp. 4309 - 4316
• Main Authors: Haberecht, Monika C., Bolte, Michael, Lerner, Hans-Wolfram, Wagner, Matthias
• Format: Book Review Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.11.2005; WILEY‐VCH Verlag; Wiley
• Subjects: Boranes; Chemistry; Chemistry, Inorganic & Nuclear; Dendrimers; Hydroboration; N ligands; Physical Sciences; Science & Technology; boranes; ELECTRONIC COMMUNICATION; N ligands; REDOX SYSTEMS; dendrimers; hydroboration; LIGANDS; COMPLEXES; METALLODENDRIMERS; CHARGE-TRANSFER; 2,2'-BIPYRIDYLBORONIUM SALTS
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200500415

The reaction of 1,4‐bis‐ or 1,3,5‐tris(bromoboryl)benzenes 4 and 6, respectively, with 2 or 3 equiv. of 4,4′‐bis(but‐3′′‐enyl)‐2,2′‐bipyridyl (2) leads to the corresponding 2,2′‐bipyridylboronium cations 5 and 7 in almost quantitative yield. Using the monocation [(MeC6H4)B(Br){4,4′‐bis(but‐3′′‐enyl)‐2,2′‐bipyridyl}]+ (3Br) as a model system, it is shown that the olefinic side‐chains of such compounds are readily transformed into alkyldibromoborane functionalities by hydroboration with HBBr2. Subsequent addition of 4,4′‐dimethyl‐2,2′‐bipyridyl leads to the formation of a branched system of three 2,2′‐bipyridylboronium cations (9Br). The species 5 and 7 can be regarded as generation zero (G0) 2,2′‐bipyridylboronium dendrimers, and the hydroboration/B–N adduct formation sequence offers a convenient route for the assembly of higher generations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)