Heterometallic Catecholates of Zirconium and Alkali Metals

Reaction of [Zr(η5-Cp’)2Cl2] (Cp’ = tBuC5H4) and Na2Cat36 (Cat36 = 3,6-di-tert-butylcatecholate) leads to the formation of the complexes [Na2Zr(Cat36)3(THF)2(C7H8)] (1) and [Zr(η5-Cp’)2(η1-Cp’)2] (2). Complex 1 along with its congeners [K2Zr(Cat36)3(THF)2] (3), [Li(THF)4][LiZr(Cat36)3] (4) and [Li4Zr(Cat36)4(dme)2] (5) were synthesized by the reaction of [ZrCl4(THF)2] and corresponding alkali metal catecholate M2Cat36. The complexes obtained were characterized by means of single-crystal X-ray diffraction and solution NMR spectroscopy (1H, 7Li, 13C). Relatively short Li···H contacts are present in the structures of complexes 4 and 5; nevertheless, DFT calculations have shown no covalent contribution to these interactions.