Effect of π-accepting substituent on the reactivity and spectroscopic characteristics of triarylbismuthanes and triarylbismuth dihalides

Triphenylbismuth(v) di[(iso)nicotinates] - transmetallation agents or divergent organometalloligands? First organobismuth(v)-based silver(i) coordination polymers

The reaction of Ph₃BiCl₂ with alkali salts of isonicotinic and nicotinic acids afforded Ph₃Bi[O(O)CC₅H₄N-4]₂ (1) and Ph₃Bi[O(O)CC₅H₄N-3]₂ (2), respectively, which were characterized by multinuclear NMR spectroscopy in solution, mass spectrometry and IR spectroscopy in the solid state. Their molecular structures were established by single-crystal X-ray diffraction. For both 1 and 2 the molecules contain a trigonal bipyramidal C₃BiO₂ core, with the phenyl groups in equatorial positions. The potential use of 1 and 2 as ditopic organometalloligands was investigated. The reaction of 1 or 2 with Me₃SnCl (1 : 2 molar ratio) resulted in carboxylato ligand exchange and the formation of Me₃Sn[O(O)CC₅H₄N-4] (3) and Me₃Sn[O(O)CC₅H₄N-3] (4) besides Ph₃BiCl₂. The crystals of both 3 and 4 contain 1-D coordination polymers built through intermolecular N → Sn interactions. The treatment of Ni[S₂P(OⁱPr)₂]₂ with 1 and 2, respectively, resulted, in addition to di(carboxylato)nickel(ii) derivatives, in isolation of Ph₃Bi and the disulphane [(ⁱPrO)₂P(S)S]₂. New coordination polymers were obtained by reacting 1 and 2 with various silver(i) salts: [Ag{Ph₃Bi[O(O)CC₅H₄N-4]₂}(OTf)] (5), [Ag{Ph₃Bi[O(O)CC₅H₄N-3]₂}(OTf)]·CH₂Cl₂ (6·CH₂Cl₂), [Ag{Ph₃Bi[O(O)CC₅H₄N-4]₂}](SbF₆)·2THF (7·2THF), [Ag{Ph₃Bi[O(O)CC₅H₄N-3]₂}](SbF₆)·CH₂Cl₂ (8·CH₂Cl₂) and [Ag{Ph₃Bi[O(O)CC₅H₄N-3]₂}(NO₃)]·CH₂Cl₂ (9·CH₂Cl₂). The crystal structures of 5 and 6 can be described as 1-D chains linked by triflate bridges in pairs of chains and 2-D networks, respectively. Compound 7 features a 2-D grid-like topology of the network, with tecton 1 acting as a tridentate ligand through both nitrogen and one oxygen atoms. The linker 2 molecules adopt either cis (compound 6) or trans (compounds 8 and 9) conformation. Complexes 8 and 9 are 1-D chain polymers exhibiting zig-zag and wavy motifs, respectively. The dimensionality of the structures is extended by the presence of supramolecular interactions (ππ, AgAg, AgO).

Hexa- and trinuclear organoantimony oxo clusters stabilized by organosilanols

Reactions of Ph2SbCl3 with RSi(OH)3 [where R = tert-Bu, cyclo-C6H11] and Ph2Si(OH)2 in toluene in the presence of triethylamine as a base were performed. Single-crystal X-ray structural elucidation of the products revealed the formation of hexanuclear antimony(V) and mixed-valent antimony (III/V) oxo-hydroxo clusters built up of an incomplete cubane subunit. Interestingly, in all the reactions, at least one Sb-C bond cleavage has been observed, leading to the formation of novel cluster assemblies [(Ph2Sb)4(PhSb)2(C4H9SiO3)2(O)6(OH)2] (1), [(Ph2Sb)4(PhSb)2(C6H11SiO3)2(O)6(OH)2] (2), [(Ph2Sb)(PhSb)2(Ph2SiO2)2(O)3(OH)2](-)Et3NH(+) (3), and [(Ph2Sb)4(Sb)2(Ph2SiO2)2(O)6(OH)2] (4), respectively.

Photoinduced synthesis of unsymmetrical diaryl selenides from triarylbismuthines and diaryl diselenides

A novel method of photoinduced synthesis of unsymmetrical diaryl selenides from triarylbismuthines and diaryl diselenides has been developed. Although the arylation reactions with triarylbismuthines are usually catalyzed by transition-metal complexes, the present arylation of diaryl diselenides with triarylbismuthines proceeds upon photoirradiation in the absence of transition-metal catalysts. A variety of unsymmetrical diaryl selenides can be conveniently prepared by using this arylation method.

Inhibition of jack bean urease by organobismuth compounds

Inhibitory activity of organobismuth compounds, triarylbismuthanes 1 and their dihalides 2 and 3, was examined against jack bean urease. Besides triarylbismuth dichlorides 2, triarylbismuth difluorides 3 and bismuthanes 1 exhibited the activity. Of all these compounds, triphenylbismuth difluoride 3a and tris(4-fluorophenyl)bismuth dichloride 2b showed the highest activity. These results indicate that generation of the inhibitory effect is not always governed by the Lewis acidity at the bismuth center. Such a tendency of inhibition by the organobismuth compounds is in good accord with that observed in the antibacterial activity against Helicobacter pylori, suggesting that H. pylori-produced urease may be a therapeutic target by bismuth-based drugs.