| dc.description | Reactions involving lithium amides and PnCl3 (Pn = P, As and Sb) were performed under different reaction conditions and stoichiometry. The sterics associated with the substituents and the size of the pnictogen atom were some of the factors that governed the compounds prepared from these reactions. The types of products isolated included aminopnictines, iminopnictines, pnictetidines and pnictenium salts. Few low coordinate compounds are known for Pn = As or Sb (i.e. iminopnictines or pnictenium salts). The use of sterically demanding substituents can provide both thermodynamic and kinetic stability with respect to saturated alternatives (i.e. pnictetidines). The bulky substituent, Mes*, facilitated the isolation of the first acyclic bisaminoarsenium salt. Sterically demanding substituents have also been used to isolate iminophosphines. Similar reactions were performed using the heavier pnictogens (As or Sb) and resulted in the isolation of pnictetidines. However, pnictetidines (for Pn = P) were observed to dissociate under certain conditions. For example, the mode of crystallisation, effects of heating or the addition of GaCl3 disrupted dimeric phosphetidines and allowed monomeric iminophosphines to be obtained. Evidence suggests that the arsetidine isolated may also be susceptible to a similar dissociation, to form the iminoarsine.* | en_US |
