Nitrogen-antimony bonds reactions with

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). 

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. ... 

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. 

The choice of SbCls appears unfortunate for technical and theoretical reasons. From the experimental point of view, SbCls catalyses the reaction of chlorinated solvents with amines, which prevents the easy and accurate study of this very important class of nitrogen bases. In the same way, the frequently used solvent hexamethylphosphoric triamide does not give reliable results with SbCls. From the perspective of the theoretical prediction of DN, the 136 electrons of SbCls and the position of Sb in the fourth row of the periodic table make quantum chemical calculations on a series of SbCls complexes difficult. Semi-empirical PM3 calculations of complexation enthalpies have been performed [38] on SbCls complexes with 12 bases. At this low calculation level, only 43% of the variance of gas-phase calculated enthalpies is explained by experimental enthalpies in CH2CICH2CI. At the ab initio or DFT level, we are aware of only two studies the first [39] on five nitriles and pyridine and the second [40] on H2S complexes with SbCls. For the pyridine-SbCls complex, the gas-phase enthalpy, calculated without BSSE, is -115.5 kJ moF while the experimental value in CICH2CH2CI amounts to —142.3 kJ mol . It must be noted that antimony is described with the use of an effective core potential that incorporates major relativistic effects. In the end, the nature of the Sb—B dative bond does not seem to have been studied in depth and no theoretical prediction of the SbCls affinity can easily be made for Lewis bases. 

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