Phosphorus-carbon-aluminum cage

The ability of phosphorus-carbon-aluminum cage compounds to function as ligands in transition metal complexes will be briefly illustrated by the example of 82 (R = i-Bu) on reaction with diiron nonacarbonyl. Coordination of the Fe(CO)4 fragment occurs exclusively at the phosphorus atom of the double bond which serves as a two-electron donor (- 83,100 %) (Scheme 6-21) [65]. 

In addition to the above-mentioned aluminum halides (Section 6.5.3.1), triorganoaluminum reagents are also able to initiate cyclooligomerization processes of the phosphaalkyne 9 a. In these reactions, aluminum is incorporated directly into the cage system. The element combination phosphorus, carbon, aluminum in a polycyclic system was previously unknown. The product palette is highly influenced by the choice of the solvent and the substituents at the metal center. 

In addition to the above-mentioned Cp2Zr-phosphaalkyne dimer complexes 59, aluminum compounds of the type 71 are also of major significance for the construction of phosphorus-carbon cage compounds, since the metal unit can be removed easily. 

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