As—N-Containing Compounds

Compounds of pentacoordinated arsenic(V) containing at least one As—N bond are summarized in Table III. Only some of these need discussion. Cycloarsa(V)azanes, which are apparently five-coordinated, have been prepared by aminolysis of pentamethoxyarsorane (75,80). Various products have been reported, depending on the nature 

Compound Melting point (°C) Physical measurements Reference 

Aminolysis of other arsenic compounds also results in the formation of cyclodiars(V)azanes (82)  

It has been suggested that dimers are probably four-membered As—N rings, with five-coordinated arsenic. However, no physical evidence is available except molecular weight measurements. Polymeric structures (XIV) may be suggested for X8As(NR)6 but again, any physical evidence is so far lacking  

The synthesis, IR, 19F-NMR, and X-ray crystal and molecular structures of XV have been reported. It is the first well-characterized four-membered As—N ring compound with arsenic atoms of coordination number five. It has been prepared by the following reaction  

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