A Reactivity Change of a Strontium Monohydroxide by Umpolung to an Acid

Controlled hydrolysis of strontium amide LSrN(SiMe3)2(thf) (L = CH(CMe2,6-i-Pr2C6H3N)2) (1) gave an unprecedented example of a hydrocarbon-soluble strontium hydroxide, [LSr(thf)(μ-OH)2Sr(thf)2L] (2). In compound 2, the tetrahydrofuran (THF) molecules can easily replaced by benzophenone and triphenylphosphine oxide to yield [LSr(μ-OH)(OCPh2)]2 (3) and [LSr(μ-OH)(OPPh3)]2 (4) compounds. Among the two strontium atoms of 2, one is coordinated to a single THF molecule, while the other is coordinated to two THF molecules. Interestingly, strontium hydroxide complex 2 behaves as an acid in its reaction with Zr(NMe2)4 and results in a heterobimetallic oxide, [LSr(μ-O)Zr(NMe2)3]2 (5). Compound 5 is dimeric in the solid state and contains a Sr2Zr2O2 core.