Magnesium mononuclear compounds

The reaction of magnesium bromide with potassium 3,5-di-tert-butylpyrazolate, K[Bu 2pz], in toluene affords Mg2(Bu 2pz)4 in THF the product is Mg2(Bu 2pz)4(THF)2." Both of these are dinuclear complexes with two bridging pyrazolato and two chelating ry -pyrazolato ligands. TMEDA binds to the unsolvated compound or displaces THF from the solvate to give Mg(Bu 2pz)2 (TMEDA), which is a mononuclear species with two ry -pyrazolates and chelating TMEDA. 

Further hydrolysis of the mononuclear oxohalides 3 may be achieved under basic conditions treatment of the dichloro derivative 3h with magnesium oxide in the presence of water gives the unusual dimer 5 (Scheme II) [43]. The formation of this particular compound may be viewed as a result of condensation of unchanged (ri -C5Me5)ReOCl2 (3b) with its (hypothetical) hydroxy derivative (ri -C5Me5)ReO(OH)2. (The... 

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