The Chemistry of 1,3,5-Triazacyclohexane Complexes. 6. Synthesis and Characterization of the Cobalt(II) Methoxide Core {Co₃(OMe)₄}²⁺

We report the synthesis and characterization of the first η3-1,3,5-trimethyl-1,3,5-triazacyclohexane (Me3TAC) alkoxo complexes. Dehydration of [Co(H2O)6](X)2 with 2,2-dimethoxypropane or HC(OMe)3 and subsequent treatment with Me3TAC results in the formation of the methoxo cube fragment clusters [{(Me3TAC)Co}3(OMe)4](X)2 (X = B(C6F5)4 (2a) and B(m-C6H3(CF3)2)4 (2b)). 2a crystallizes in the triclinic space group P1̄ (a = 13.857(2) Å, b = 16.843(3) Å, c = 19.318(2) Å, α = 79.23(2)°, β = 76.855(13)°, γ = 70.10(2)°, Z = 2) and 2b in the monoclinic space group P21 (a = 12.710(3) Å, b = 23.251(3) Å, c = 18.702(4) Å, β = 101.16(2)°, Z = 2). The cations contain a {Co3(OMe)4} cube fragment core with an η3-Me3TAC bonded to each cobalt atom. Me3TAC is bonded unsymmetrically due to hydrogen-bonding interactions with the anions. This broken symmetry can also be observed as solvent-, anion-, and H/D isotope-dependent splitting of the signals in 1H and 2H NMR. A byproduct of the reaction is the protonated Me3TAC. The analogous monoacid adduct Me3TAC·HCl has been characterized by X-ray crystallography (orthorhombic space group Pbca, a = 11.0366(9) Å, b = 12.2986(6) Å, c = 13.9949(7) Å, Z = 8).