Group 15 elements pyridine analogues

Unlike silabenzene (p. 12 5), pyridine analogues of the Group V elements are quite robust, although their stability decreases from phosphorus to bismuth. The... 

Although the Group 2 element analogues have not yet been prepared, there are a number of derivatives of /-Bu-substituted pyrazolylborates that provide good steric protection of coordination sites because of the large size of the /-Bu substituent. For example, In[HB(3-f-Bupz)3] (Fig. 23) was recently prepared and shown to be a rare example of an inert, monomeric In(I) compound.115 Pyridyl-substituted pyrazolylborates have also been employed in the synthesis of homoleptic transition metal (Ti) and Group 13 pyrazolylborate compounds (Tl).116 The pyridine substituent acts in the dual capacity of both sterically and coordinatively saturating the metal centers. 

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