Opening of the azastibol heterocycle with various acids: Isolation of novel N,C-chelated organoantimony(III) compounds

The reaction of N,C-intramolecularly coordinated organoantimony(III) compound L2SbCl (1) (where L is [2-(2′,6′-i-Pr2C6H3)Ndouble bond; length as m-dashCHC6H4]) with one molar equivalent of the K-selectride (K[B(s-Bu)3H]) gave compound LSb{2-[CH2N(2′,6′-i-Pr2C6H3)]C6H4} (2) containing five membered aza-stiba heterocycle. On the contrary, analogical reaction between the organobismuth(III) compound L2BiCl (3) and K-selectride gave only inseparable mixture of products. Reactions of 2 with selected acids HX resulted in the cleavage of the present Sb–N bond and formation of novel N,C-chelated compounds LSb(X){2-[CH2NH(2′,6′-i-Pr2C6H3)]C6H4} (where X = Cl (4), CH3COO (5), CF3COO (6), CF3SO3 (7) or FcCOO (8); Fc = ferrocenyl). Compounds 4–8 were characterized by the help of elemental analysis, electrospray ionization (ESI) mass spectrometry, multinuclear NMR spectroscopy, IR spectroscopy and in the case of 5 by the single-crystal X-ray diffraction analysis. The molecular structures of compounds LSb(X){2-[CH2NH(2′,6′-i-Pr2C6H3)]C6H4}·HX (where X = CF3COO (6a), CF3SO3 (7a)) were determined by the single-crystal X-ray diffraction analysis as well. Compounds 6a and 7a are most probably products of partial hydrolysis of compounds 6 and 7.