Transition-Metal Complexes Containing Alkynylsilyl Functionalized η6-Arene Ligands

Six transition-metal arene complexes containing alkynylsilyl groups have been synthesized. Direct complexation of the corresponding arenes yielded the alkynylsilylarene complexes PhC CMe2SiPhCr(CO)(3) (1), n-PrC CMe2SiPhCr(CO)(3) (2), n-PrC CMe2Si-SiMe2-SiMe2PhCr(CO)(3) (4), and PhC CMe2SiPhMo(CO)(3) (6), while PhC CMe2Si-SiMe2PhCr(CO)(3) (3) and (PhC CMe2SiPh)(2)Cr (7) were synthesized by modification of precomplexed arenes. The reactivity of the C C triple bonds of the synthesized alkynylsilyl compounds toward complexation and carbon-carbon bond-forming reactions was studied. The alkynyl groups of 1 and 6 underwent intermolecular complexation to yield the trinuclear compounds 1 center dot Ni2Cp2 (8) and 6 center dot Cp2Mo2(CO)(4) (9), respectively, while reaction of 7 with CpCo(PPh3)(2) led to intramolecular [2 + 2] cycloaddition of its two alkynyl groups with formation of the dinuclear cyclobutadiene complex CpCo(PhCCSiMe2Ph)(2)Cr (10). All of these complexes were characterized by NMR, IR, and mostly also UV/vis (1, 2, 6-10) spectroscopy. The molecular and crystal structures of compounds 1, 2, and 6-10 were determined by single-crystal X-ray diffraction.