Characterization and thermal activation of adducts of Group 4 tetrahalides with 1,2-dialkoxyalkanes

Coordination compounds of general formula MX4[κ2-O(R)CH2CH(R′)OR′′], 2a–i, have been prepared in high yield upon addition of a variety of 1,2-dialkoxyalkanes, ROCH2CH(R′)OR′′, to MX4 (M = Ti, X = F, 1a, I, 1b; M = Zr, X = Br, 1c, I, 1d). The new complexes have been characterized by elemental analysis and NMR spectroscopy. The thermal stability of 2 has been studied. Fragmentation of the TiI4 adducts takes place in chloroform solution at 90 °C: after hydrolysis of the reaction mixtures, MeI and CH2ICH2I have been detected from TiI4[dme] [dme = MeO(CH2)2OMe], MeI and Me2O from TiI4[MeOCH2CH(Me)OMe], and MeI, CH2ICH2I, Me2O, CH2ClI from TiI4[MeO(CH2)2OCH2Cl]. The diether MeO(CH2)2OCH2Cl is thermally activated also when coordinated to ZrX4 (X = Br, I): after hydrolysis, MeBr, CH2BrCH2Br, O(CH2CH2Cl)2 and Me2O (X = Br) and MeI, CH2ClI and CH2ICH2I (X = I) have been found, respectively.