Phosphorus and Germanium

Germyl phosphine derivatives can be made by reactions analogous to (9.166), (9.169) through (9.172), or by the action of phosphine on compounds with Ge-N or Ge-Cl bonds (9.296, 9.297). Some germyl 

3 PhjGeCl + PH3 (Ph3Ge)3P + 3HC1 3 HjGeCl + (HjSOjP (H3Ge)3P + 3H3SiCl 

Phenyldichlorogermane will produce cyclic dimers and trimers in a reaction analogous to Equations 9.220 and 9.319. Similarly the adamantane-type analogue of Equation 9.242, (PhGe)4 (PPh)g, is made from PhGeCl3 and K2PPh (9.300). 

Complexes (9.302a,b) contain Ge and Ge valency states, respectively [11,12]. 

The action of lithium aluminium phosphide on dimethyl dichlorogermane is to produce dimeth-ylgermyl phosphine, which, on heating to 120°C and condensing, transforms into another adaman-tane/(P40io)-type molecule of formula (Me2Ge)6P4. Phosphine is liberated on treatment with hydrogen chloride. 

---

In all the molecules studied so far, chirality arises because of the presence of a tetrahedral carbon chiral center. Chiral centers are not limited to carbon. Following are stereorepresentations of a chiral cation in which the chiral center is nitrogen. We discuss the chirality of nitrogen centers in more detail in Section 23.3. Enantiomers of tetrahedral silicon, phosphorus, and germanium compounds have also been isolated. 

---