Arsenic carbon—antimony bonds

Metal-carbon multiple bonds, arsenic, antimony, bismuth,... 

Anions derived from tin, phosphorus, arsenic, antimony, sulfur, selenium, and tellurium are known to react at the heteroatom to form a new carbon-heteroatom bond in good yields. 

We have essentially exhausted all of the directly measured enthalpies of formation of compounds containing carbon-arsenic, -antimony and -bismuth bonds. However, let us now make use of other thermochemical data and see what can be derived using some plausible estimates. And barring that, let us see what new enthalpies of formation would become available if only some new measurement were made. 

These X-rays studies show that the interaction is greater in the case of antimony than in the case of arsenic. Despite the greater size of antimony than arsenic, the Sb — O distance is shorter than the As—O distance. In addition the Sb—C (ylidic) and As—C(ylidic) bond distances indicate that the Sb—C bond has more double-bond character than the As—C bond. In all cases these ylides take up Z,Z-conformations, both in solution (as observed by NMR spectra) and in the solid state, but in the solid state they are not symmetric, only one of the substituent groups being involved in the intramolecular interaction. This can be represented as in 40 and 41. In accord with such structures one of the bonds linking substituents to the ylidic carbon atom is shorter than the other. 

The trichlorides and tribromides of arsenic and of antimony react with [Fe(A -C5H5)(CO)2l2 by insertion of MXg, or of MXa+ arising from the self-ionization 2MXs MXa+ + MX4", into the iron-iron bond. Indium(i), as InaBri, inserts into carbon-bromine and into carbon-iodine bonds, and into metal-metal and metal-halide bonds as in Mn2(CO)io, MnCl(CO)6, or AuCKPPhg). ... 

Many of the properties of the group 15 element diheteroferrocences are very similar to ferrocenes and other metallocenes. It seems justified to regard the diheteroferrocenes as perturbed ferrocenes just as we regard the group 15 heterobenzenes as perturbed benzenes. Thus, it is very clear that the elements phosphorus, arsenic, antimony, and bismuth can take part in 7r-bonding in a manner similar to carbon. 

The SRN1 process has proven to be a versatile mechanism for replacing a suitable leaving group by a nucleophile at the ipso position. This reaction affords substitution in nonactivated aromatic (ArX) compounds, with an extensive variety of nucleophiles ( u ) derived from carbon, nitrogen, and oxygen to form new C—C bonds, and from tin, phosphorus, arsenic, antimony, sulfur, selenium, and tellurium to afford new C-heteroatom bonds. 

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