We previously described efficient syntheses of ammonium and potassium magnesium dodecaborates, (NH4)2MgB12O20●10H2O (1) and K2MgB12O20●10H2O (2), and their potential use in oil and gas recovery involving delayed crosslinking in hydraulic fracturing fluids, as well as other possible applications (1-3). These compounds contain the hexaborate anion, [B6O7(OH)6]2-, coordinated to the central octahedral metal atom in bidentate mode along with coordinated water molecules. Here we describe further chemistry of these versatile compounds, which may serve as valuable reagents to prepare many other potentially useful borates. We focus here on reactions involving the facile exchange of magnesium for transition metals under mild conditions to provide analogous dodecaborates of compositions (NH4)2MB12O20●10H2O and K2MB12O20●10H2O, where M is Mn, Co, Ni, etc. Also discussed are reactions leading to other non-analogous borates, as well as exchange reactions of the ammonium and potassium cations of 1 and 2 with various alkali metal and non-metal cations. K2MgB12O20●10H2O + MX2 → K2MB12O20●10H2O + 2 KX (M = Mn, Co, Ni, etc.) (NH4)2MgB12O20●10H2O + MX2 → (NH4)2MB12O20●10H2O + 2 NH4X (M = Mn, Co, Ni, etc.)

Facile metal exchange reactions of ammonium and potassium magnesium dodecaborates

255th National Meeting (2018)

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