Heavier pnictogens

Solid-state assemblies containing binary group 15/16 anions of the heavier pnictogens are also extremely well known, including the naturally occurring... 

The occurrence of E-E and, in some cases, E-C bond activation in the reaction of the cyclic ligands (RE) with transition metal complexes becomes more prevalent for the heavier pnictogens (E = As, Sb, Bi). The reaction of... 

Cyclodipnict(III)azanes may exist as cis or trans isomers, cf. cyclodipho-sph(III)azanes (Section 11.4.1). The solid-state structures of the dichloro derivatives [ClE( i-N Bu)]2 (E = As, Sb ) reveal a cis configuration however, the derivatives [XSb(p-N Bu)]2 (X = N3, O Bu), prepared by nucleophilic substitution reactions, are isolated as trans isomers. In general, there is a trend towards the preferential formation of trans isomers in the solid state for the heavier pnictogens.In solution, however, NMR data indicate the existence of cis and trans isomers for some derivatives. In the case of the bisamido derivative [DippN(H)Sb()i-N Bu)]2, both the cis and trans isomers have been structurally characterised (Figure 11.23). ... 

Carbene adducts of the heavier pnictogen pentaflu-orides have been reported. Reaction of AsFs or SbFs with carbene (1) (R = Mes, R = Cl) in 1,3-bis(trifluoromethyl)benzene resulted in the isolation of(l) AsF5 (112) and (1) SbFs (113). The crystallographic analysis for (112) and (113) reveals the expected octahedral geometry at the pnictogen center with a long As C (2.009(5)A) and Sb-C (2.175(5)A) bond distance respectively. Recently, a novel hypervalent antimonide complex was reported. The nucleophihc addition of carbene (1) (R = Mes, R = H) to Sb(CF3)3 (equation 12) resulted in the... 

Unlike nitrogen, the heavier pnictogens do not form true multiple bonds with ease. Thus, molecules such as POCI3 are better viewed as C13P+-0 , as opposed to Cl3P=0. In this newer view, the shortness of the P-O linkage (1.58 A) is attributed to its ionic rather than double-bond character. 

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