Nitrogen-antimony bonds

Although antimony-nitrogen bonds are unstable to hydrolysis, many well-characterized compounds where antimony atoms are bonded exclusively to nitrogen atoms are known.They include tris-amido species, for example, Sb(NR2)3, formed by the reaction of SbCls with secondary amines (equation 5). 

Boranes 1 and 2 in equation 89 react with 2-fluoro-1,3-dioxa-2-phospholanes to give nng expansion products as the corresponding antimony analogues yield the products of msertion of nitrogen into the antimony-fluorme bond [775] (equation 89) (Table 31)... 

The reaction of SbCl3 with [(PNR)2(NRLi THF)2] leads to a polycyclic cage complex of the formula [(PNR)2(NR)2 Sb]Cl where antimony is bonded to three nitrogen and one chlorine atom. Antimony in a square planar environment of four nitrogen atoms exists in porphyrins and related macrocycles. Sb-N bonds also exist in antimony azides. The mixed chloride diazide SbCl(N3)2 is formed from NaNs and SbCfr at room temperature. ... 

The ylides have been classified on the basis of the heteroalom covalently bonded to the carbanion. Accordingly, they can be differentiated into nitrogen ylide (Scheme 2), sulfur ylide Scheme 3, phosphorus ylide Scheme 4, arsenic ylide Scheme 5, antimony ylide (Scheme 6), bismuth ylide (Scheme 7) and thallium ylide (Scheme 8). 

Compounds with triple bonds, i.e. acetylenic compounds, continue to receive attention. Patents have been filed for mixtures of propargyl alcohol with, for example, cellosolve + a phenol formaldehyde resin + tar bases heterocyclic nitrogen compounds + acetylenic + dialkylthiourea or a quaternary + antimony oxide . 

The chemistry of antimony and nitrogen is not as rich as that of arsenic and nitrogen. The N—Sb bond mainly exists in compounds where N is but one of a number of donor atoms. These compounds, where significant, will be dealt with under various other headings (mainly oxo and halogen ligands). Some Sb—N bond data are assembled in Table 12. 

In contrast, use of metalloid elements, such as silicon, tin antimony or boron, which can form weak covalent bonds with oxygen, nitrogen or sulfur substituents during the course of the reaction, results in templated products that may be obtained metal-free by simple hydrolysis. These covalent template reactions (the M—X bond is essentially covalent in these cases) also have the advantage that the... 

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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