Arsine derivatives nitrogen

Elements which form pyramidal bonding also form optically active compounds provided the groups are different. To this class belong derivatives of trivalent nitrogen, phosphines, arsines or stibines. 

Generally, chiral tricoordinate centers are configurationally stable when they are derived from second-row elements. This is exemplified by sulfonium salts, sulfoxides and phosphines. In higher rows, stability is documented for arsines and stibines. In contrast, tricoordinate derivatives of carbon, oxygen, and nitrogen (first-row atoms) experience fast inversion and are configurationally unstable they must therefore be viewed as conformationally chiral (see Fig. 3, Section 3.b). Oxonium salts show very fast inversion, as do carbanions. Exceptions such as the cyclopropyl anion are known. Carbon radicals and carbenium ions are usually close to planarity and tend to be achiral independently of their substituents [21-23]. 

It has already been stated that Bart used catalysts in his reaction, in order to eliminate the diaze-nitrogen at low temperatures and thus decrease the formation of by-products. In Schmidt s method, in addition to non-arseuated aromatic derivatives, arsenated derivatives may also occur as by-products. In the case of the preparation of phenyl-arsinic acid, the by-product is diphenylyl-4-arsinic acid, CgH4.Ph. AsO(OH)2, and the presence of such a derivative can only be accounted for on the assumption that one of the hydrogen atoms of tire benzene nucleus becomes labile at the moment when the replacement of the diazo-group by the arsinic acid grouping takes place. 

Systems of the form Rh(L-L -BID)(CO)(YR3)2 that contained a five-membered monochatged bidentate ligand of the type L-L -BID (L,L -BID = monochatged bidentate ligand with donor atoms L,L variations of oxygen, nitrogen, and sulfur), such as cupferrate or tropolonate and derivatives, showed a tendency to accommodate an additional phosphine/arsine ligand (YR3, Y = P, As). ... 

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