Synthetic and X-ray diffraction studies of borosiloxane cages [R ' Si(ORBO)(3)SiR '] and the adducts of [(BuSi)-Si-t{O(PhB)O}(3)SiBut] with pyridine or N,N,N ',N '-tetramethylethylenediamine

Eleven borosiloxane [R'Si(ORBO)(3)SiR'] compounds where R-' = Bu-1 and R = Ph (1), 4-PhC6H4 (2), 4-(BuC6H4)-C-t (3), 3-NO2C6H4 (4), 4-CH(O)C6H4 (5), CpFeC5H4 (6), 4-C(O)CH(3)C(6)H4 (7), 4-ClC6H4 (8), 2,4-F2C6H3 (9), and R-' = Cyclo-C6H11 and R = Ph (10), and 4-BrC6H4 (11) have been synthesized and characterized by spectroscopic (IR, NMR), mass spectrometric and, for compounds where R-'= Bu-1 and R = 4-PhC6H4 (2), 4-(BuC6H4)-C-t (3), 3-NO2C6H4 (4), CpFeC5H4 (6) and 2,4-F2C6H3 (9), X-ray diffraction studies. These compounds contain trigonal planar RBO2 and tetrahedral (RSiO3)-Si-' units located around 11-atom "spherical" Si2O6B3 cores. The dimensions of the Si2O6B3 cores in compounds 2, 3, 4, 6 and 9 are remarkably similar. The reaction between [(BuSi)-Si-t{O(PhB)O}(3)SiBut] (1), and excess pyridine yields the 1:1 adduct [(BuSi)-Si-t{O(PhB)O}SiBut]. NC5H2 (12) while the reaction between 1 and N,N,N',N'-tetramethylethy-lenediamine in equimolar amounts affords a 2:1 borosiloxane:amine adduct [(BUSi)-Si-t{O(PhB)O}(3)SiBut](2) center dot Me2NCH2CH2NMe2 (13). Compounds 12 and 13 were characterised with IR and (H-1, C-13 and' B-11) NMR spectroscopies and the structure of the pyridine complex 12 was determined with X-ray techniques. (c) 2006 Elsevier Ltd. All rights reserved.