SYNTHESIS AND REACTIONS OF SOME FUNCTIONALLY SUBSTITUTED SILA- AND GERMACYCLOPENTADIENES

The synthesis of a series of halogen-substituted sila- and germacyclopentadienes (I) is described. A survey of the reactionsof these compounds shows that the ring structure often provokes a reactivity not expectedon the basis of analogy with acyclic silanes and germanes. The formation of anions derived from I is discussed, and equilibrium experiments (reaction 14) indicate that pentaphenylgermole (XIII) is at least 106 times more acidic than triphenylgermane. A spectrophotometric determination of the acidity of triphenylgermane in DMSO gave a value of 23.0 for the pXa. The acidity of the germole, XIII, could not be determined in the same manner, pre-cluding an accurate determination of its pKa. Several compounds containing σ bonds to transition metal carbonyls (I, R″ = transition metal carbonyl moiety) were synthesized and attempts to rearrange these to π-bonded “sandwich” compounds are reported. © 1969, American Chemical Society. All rights reserved.