Use of heterodifunctional ligands to bridge “early” and “late” transition metals. Construction and chemistry of complexes containing indirectly linked cobalt carbonyl and zirconocene units

Four zirconocene systems, each containing tertiary phosphine functionality indirectly linked to either or both cyclopentadienyl rings, are described. Unlike the phosphinomethylzirconocenes, in which the metal and the phosphine strongly influence each other's basic chemistry, it has been found that a variety of transformations may be carried out at either site on the more indirectly linked systems without interference from the other. Thus reduction and hydrozirconation proceed normally at the Zr center, and quaternization and complexation to a second metal may be achieved at the phosphine. Two “early-late” multimetallic systems containing Zr and Co have been prepared. Reduction and acylation at Co proceed without interference from Zr; however, attempts to generate hydrides at Zr in the bimetallic systems were unsuccessful.