Nitrogen-bismuth bonds

The bismuth-nitrogen bonds in these compounds are labile and decomposition slowly occurs at room temperature they may be stored at —78°C. Some reactions are shown in Scheme 7. 

There are a large number of compounds which contain bismuth-nitrogen bonds, but very few in which such bonding represents the main framework of the bonding. There does exist BiCls coordination compounds such as the stable colourless [BiCl3(NH3)3] or the unstable red [(BiCl3)2(NH3)]. These compounds are described in more appropriate sections, except where a point about the Bi—bond is being made. 

Bismuth is the fifth member of the nitrogen family of elements and, like its congeners, possesses five electrons in its outermost shell, 6s 6p. In many compounds, the bismuth atom utilizes only the three 6p electrons in bond formation and retains the two 6x electrons as an inert pair. Compounds are also known where bismuth is bonded to four, five, or six other atoms. Many bismuth compounds do not have simple molecular structures and exist in the solid state as polymeric chains or sheets. 

Like nitrogen, phosphorus, arsenic, antimony and bismuth usually bond to silicon in the III valence state. NMR and vibrational spectra indicate a pyramidal structure... 

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). 

Metals may also be linked through an oxygen or nitrogen atom to form a stable metal complex without a carbon-metal bond. These include metal complexes of ethylenediamine tetraacetate (EDTA), diethylenetriamine pentaacetate (DTPA), or ethylenediamine tetramethylphosphonate (EDTMP). Metalloid compounds include antimonyl gluconate and bismuth salicylate. 

MeCN)][SbCl6]3 (106) have also been isolated. The dication has bismuth encompassed by the crown ether and bonded to all ether oxygen atoms, and the chlorine atom [Bi-Cl 2.479(6) A] and the pair of acetonitrile nitrogen atoms [Bi-N 2.82(2) and 2.86(3) A] are bound from the opposite side to the crown ether. The trication adopts a sandwich structure in which bismuth is bound to all four oxygen atoms of each crown ether [Bi-0 2.436(5) and 2.545(5) A]. The acetonitrile nitrogen atom occupies a position between the two ligands [Bi-N 2.650(9) A],... 

Scheme 3 shows the conceivable reaction sites of alkenylbismuthonium salts, alkynylbismuthonium salts, bismuth ylides, and bismuth imides in carbon-carbon and carbon-heteroatom bond forming reactions. In the initial step, nucleophiles (Nu) attack the positively charged bismuth(V) center, a-proton or (3-carbon (Scheme 3a, b) whereas electrophiles (El) attack the negatively charged a-carbon or a-nitrogen (Scheme 3c, d). Usually, the resulting bismuth(V) intermediates... 

Dalzin (bis(allylthiocarbamido)hydrazine) forms sparingly soluble complexes (29) in which it is bonded through sulfur and nitrogen atoms (Section 10.2.7) but the bright orange-red bismuth complex can be extracted into chloroform for a spectrophotometric determination provided cyanide is present to mask copper. 1,4-Diphenylthiosemicarbazide PhNHNC(SH)NHPh can be used for the spectrophotometric determination of ruthenium after extraction of its violet-red complex into chloroform. 

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