Synthesis and Structural Study on Organoantimony(III) and Organobismuth(III) Hydroxides Containing an NCN Pincer Type Ligand†

The reactions of the dimeric organoantimony(III) oxide [LSbO] 2 ( 3 ), containing the NCN chelating ligand L (L = C 6 H 3 -2,6-(CH 2 NMe 2 ) 2 ) with trifluoroacetic acid and trifluoromethanesulfonic acid gave the unprecedented organoantimony hydroxides LSb(OH)(X) (X = CF 3 CO 2 ( 6 ), CF 3 SO 3 ( 7 )). On the other hand, analogous reactions with acetic acid and tetrafluoroboric acid led to a polar group exchange, providing the compounds LSbX 2 (X = F( 4 ), CH 3 CO 2 ( 5 )). Analogously, the organobismuth oxide [LBiO] 2 ( 8 ) gave the acetate LBi(O 2 CCH 3 ) 2 ( 9 ) in its reaction with acetic acid but the hydroxide LBi(OH)(CF 3 SO 3 ) ( 10 ) was obtained when trifluoromethanesulfonic acid was used. All compounds were characterized with the help of elemental analysis, ESI mass spectrometry, and 1 H and 13 C NMR spectroscopy, and their molecular structures were determined by X-ray diffraction techniques. The molecular structures of hydroxides 6 and 7 may be described as being built up from the organoantimony cation [LSb(OH)] + effectively stabilized by the NCN ligand L and the counteranion X −, which is connected to the terminal Sb−OH moiety through the hydrogen bond Sb−OH···X. The organobismuth analogue 10 forms the weakly bonded dimeric units LBi(μ-OH) 2 BiL, and the triflate anions are connected to the bridging OH moieties via the hydrogen bonds as well as to the bismuth centers through Bi−O interactions, leading to an infinite chain supramolecular structure of 10 .