Base promoted successive dealkylation steps of molybdenum alkoxides leading to a row of novel 1D and 2D polymeric frameworks of potassium-molybdenum oxomethoxides

摘要

The MoCl5 methanolysis reaction, in the presence of basic agents providing weakly alkaline media, leads to the formation of a Mo-Mo triply bridged anionic dimeric complex with a solvated potassium counterion, [K(CH3OH)(2)Mo2O2(mu(2)-OCH3)(3)(OCH3)(4)] (1), that represents the first structurally characterized Mo-K oxoalkoxide. Here we describe its further reactivity, i.e. the MoCI5 methanolysis reaction in the presence of an additional equivalent of base which leads to demethylation of the one of mu(2)-bridging alkoxides, thus giving an unusual oxo-, dimethoxo-bridged cluster, [K-2(CH3OH)Mo2O2(mu(2)-OCH3)(2)(mu(2)-O)(OCH3)(4)] (2). Subsequent transformation with the generation of the formally (Mo-Mo}(4-) species in [K-4(CH3OH)(6)Mo-2 O-2(mu(2)-O)(2)(OCH3)(2)(CO3)(2)] (3) was achieved via addition of an extra amount of base in the presence of potassium carbonate along with providing more vigorous reaction conditions. (C) 2014 Elsevier Ltd. All rights reserved.