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A series of novel first-generation silicon-centred tin dendrimers Si(CH2CH2SnR3)4 [R = CH3 (3), iBu (4), C≡CCH3 (5), C6H4CH3-4 (6), C6H4OCH3-4 (7), (CH2)4OCH2CH2OCH3 (8), CH2SiMe3 (9)] was prepared by the reaction of Si(CH2CH2SnBr3)4 (2) with the appropriate Grignard reagent or LiCH2SiMe3 in tetrahydrofuran. The new compounds were characterized by multinuclear NMR studies (1H, 13C, 119Sn), mass spectrometry (MALDI-TOF, EI) and elemental analyses. The molecular structure of Si[CH2CH2SnBr3(THF)2]2[CH2-CH2SnBr3(THF)]2 (2a) was determined by single-crystal X-ray diffraction. [Copyright &y& Elsevier]

Abstract: The synthesis of the first all-tin-dendrimer Sn[(CH2)4SnPh3]4 (2) results from complete hydrostannation of tetra(but-3-enyl)stannane (1) with triphenyltin hydride. Selective cleavage of one phenyl group from each dendron of 2 with anhydrous HCl results in Sn[(CH2)4Sn(Cl)Ph2]4 (3), which on treatment with LiAlH4 yields the corresponding hydride derivative Sn[(CH2)4Sn(H)Ph2]4 (4) containing four reactive Sn–H bonds. The cyclopentadienyl derivative Sn[(CH2)4Sn(C5H5)Ph2]4 (5) as well as the transition metal substituted derivatives Sn[(CH2)4Sn{Co(CO)4}Ph2]4 (6), Sn[(CH2)4Sn{Fe(CO)2C5H5}Ph2]4 (7), and Sn[(CH2)4Sn{Mn(CO)5}Ph2]4 (8) have been prepared by coupling of 3 with the appropriate Grignard or sodium derivatives of the transition metal moieties. The new compounds were characterized by elemental analyses, IR, 1H-, 13C- and 119Sn NMR spectroscopy and MALDI-TOF mass spectrometry. [Copyright &y& Elsevier]