Direct Synthesis of Pentaarylcyclopentadienyl Sandwich and Half-Sandwich Complexes of s-, p-, and d-Block Metals

The sterically demanding pentaarylcyclopentadienyl radical CpBIGt-Bu center dot (1; CpBIGt-Bu = Cp(4-t-Bu-Ph)(5)) reacts with group 2, group 13, and group 14 metal amalgams to form the following complexes of the type Cp(2)(BIGt-Bu)m (M = Ca (3), Sr (4), Ba (5)), CpBIGt-BuM' (M' = Ga (6), In (7), Tl (8)) and Cp2BIGt-BuM '' (M '' = Sn (10), Pb (11)). In addition, metallocenes (Cp2Mg)-Mg-BIG (2) , (Cp2Hg)-Hg-BIG (12), and (Cp2Ge)-Ge-BIG (9) were formed in reactions of 1 with magnesium anthracene (2) and elemental mercury (12) as well as by salt metathesis between CpBIGt-BuK and GeCl2 center dot dioxane (9). 6 was found to react with (coe)Cr(CO)(5) (coe = cis-cyclooctene) with formation of CpBIGt-BuGaCr(CO)(5) (13). 2-13 were characterized by elemental analysis and IR and NMR spectroscopy. In addition, the solid-state structures of 2, 4, 5, and 9-13 were determined by single-crystal X-ray diffraction.