Organoantimony-oxygen compounds

Tetraorganoantimony(V) alkoxides and triorganoantimony(V) dialkoxides are monomeric, five-coordinate compounds, e.g. PluSbOMe and Ph3Sb(OMe)2 [420]. This is not surprising, because the trigonal bipyramidal geometry found in these compounds is a preferred coordination mode of antimony(V). Despite this, tri-phenyl(4-nitrocatecholato)antimony(V) was found to dimerize via Sb- - -O second- 

One structurally characterized monoorganoantimony alkoxide is the dimer [MeSbBr2(Ai-OMe)]2, with identical bridging Sb-O(Me) interatomic distances (Sb-O 2.135 A) which are, however, longer than the terminal Sb-O(Me) distances (1.962 A) [422]. 

Organoantimony carboxylates can be expected to self-assemble. Diphenylanti-mony(III) acetate consists of self-assembled chains, 166, with bridging acetato groups and pseudo-trigonal bipyramidal coordination [423]. 

Surprisingly few organoantimony carboxylates have been structurally characterized. One might expect that further examples of self-assembly in this class of compounds will be identified if systematic structure investigation (as performed for organotin carboxylates) were to be conducted. 

Organophosphorus acids can play a similar role - bridging antimony atoms with the formation of self-assembled structures. The monothiophosphinate, Me4SbOP(S)Me2, is one example. On the basis of Mossbauer spectra a dimeric structure has been postulated for this compound [424] an X-ray diffraction study 

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Reaction of organoantimony and -bismuth halides with various oxygen nucleophiles gives the corresponding oxygen compounds. Several examples are shown in equations... 

Organoantimony(III) and -bismuth(III) compounds containing electronegative atoms such as halogen, oxygen and so on show Lewis acidic character. Thus, tetracoordinate anions and even pentacoordinate dianions have been prepared from the corresponding halides or pseudohalides, and several of the compounds have recently been fully characterized by X-ray crystallography. Several examples are shown in equations 162 , 163 , 164 , 165 , 166 , 167 , 168 and 169 ... 

Several oxygenated organoantimony compounds have been prepared by reaction of oxygen nucleophiles with triorganoantimony alkoxides, imines and oxides. Several examples are shown in equations 264 °, 265 , 266 and 267. ... 

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