Synthesis and Structures of s- and p-Block Metal Complexes Containing Sterically Demanding Pentaarylcyclopentadienyl Substituents

The synthesis of alkali metal salts of sterically demanding cyclopentadienyls CpBIGi-PrM (CpBIGi-Pr = Cp(4-i-Pr-Ph)(5); M = Li 1, Na 2, K 3, Rb 4, Cs 5), CpBIGn-BuM (CpBIGn-Bu = Cp(4-n-Bu-Ph)(5); M = Li 6, Na 7, K 8, Rb 9, Cs 10), and CpBIGt-BuM (CpBIGt-Bu = Cp(4-t-Bu-Ph)(5); M = Li 11, Na 12, K 13, Rb 14, Cs 15) and their complete characterization including IR and heteronuclear (H-1, C-13, Li-7, Na-23, Rb-87, Cs-133) NMR spectroscopy are reported. In addition, the solid-state structures of 5, 10, 11, and 13 were determined by single-crystal X-ray diffraction, revealing the formation of infinite one-dimensional chain structures in the solid state (5, 10) or solvent-separated ion pairs (11, 13). Salt elimination reactions of CpBIGt-BuK 13 with ECl3 yielded the monosubstituted cyclopentadienyl compounds CpBIGt-BuECl2 (E = P 16, As 17, Sb 18, Bi 19), which were characterized by elemental analysis, IR, and heteronuclear (H-1, C-13, P-31) NMR spectroscopy and single-crystal X-ray diffraction (17).