Reaction Of Bismuth Research Articles

Molecular Assemblies Based on Cp*BiX2 Units (X = Cl, Br, I): An Experimental and Computational Study

A series of pentamethylcyclopentadienyl-substituted bismuth halo complexes were prepared by the reactions of bismuth(III) halides BiX3 (X = Cl, Br, I) with LiCp* (Cp* = C5Me5) in 1:1 ratio. The crystal structures of [Cp*5Bi6Cl12][(thf)2Bi2Cl7] (1), [Cp*BiBr2]∞ (2), [{Cp*5Bi5Br9}{BiBr4}]2 (3), and [Cp*BiI2]∞ (4) were determined by single-crystal X-ray diffraction analysis. 1–4 display different types of aggregation, polymeric association, and Cp*–BiX2 bond hapticity depending on the halogen atom at Bi. The cationic portion of 1 is a distorted octahedral Bi6 cage that shows no Bi–Bi bonding, is capped by halo ligands and Cp* rings in a η5-fashion, and contains an interstitial Cl atom. The main structural difference in the bismuth halide framework between cationic portions {Cp*5Bi5Br9}+ in 3 and [Cp*5Bi6Cl12]+ in 1 is a neutral BiX3 unit complexed to the [{Cp*5Bi5Cl9}]+ fragment of the latter. 2 and 4 are zigzag polymers with different types of intermolecular interaction in the crystals. More ionic Cp*–Bi bonding results in higher hapticity and appears to favor cage formation, while more covalent bonding favors lower hapticity. According to quantum chemical calculations on the simplified gas phase models Cp*BiX2 (X = F, Cl, Br, I), the Cp* ring is attached via a η1(π)-bonding mode. The structural diversity of the observed assemblies is driven by the nature of Cp*–Bi bonding, which was examined by NBO analysis.

An Ionic Liquid Based Single Step Room Temperature Route for the Synthesis of Molybdenum Cluster Compounds

AbstractA soft and convenient single step route is developed to synthesize molybdenum cluster compounds using an ionic liquid as reaction medium. Bi[Mo5Cl13]Cl and [BiCl][Mo6Cl14] were isolated from the ionic liquid [BMIM]Cl/AlCl3 ([BMIM]+: 1‐n‐butyl‐3‐methylimidazolium) and characterized. Black, cubic crystals of Bi[Mo5Cl13]Cl are obtained at room temperature by the reaction of bismuth, BiCl3, and MoCl5 in Lewis‐acidic ionic liquid [BMIM]Cl/AlCl3. Bi[Mo5Cl13]Cl crystallizes in the cubic space group Pn$\bar{3}$ with a = 1291.6(3) pm. In the [Mo5Cl13]2– cluster, the molybdenum atoms form a square pyramid with Mo–Mo bond lengths 258.9(2) pm and 259.5(2) pm. The structure is a defect variant of the Pb[Mo6Cl14] type; in statistical distribution one of the molybdenum atoms is missing in the cluster core. The bismuth(III) cations, which are in octahedral coordination by the apical chloride ions of the clusters, connect the cluster anions into a three dimensional network. Light red crystals of monoclinic [BiCl][Mo6Cl14] were obtained by the oxidation of bismuth with MoCl5 in [BMIM]Cl/AlCl3. The structure determination is in excellent agreement with literature data of crystals obtained by high temperature syntheses.

Electronic states and spectra of BiTe

NIR/VIS emission spectra of the bismuth telluride radical, BiTe, were measured in the 3600–20 000 cm −1 region with a Fourier-transform spectrometer. BiTe was produced by reaction of bismuth and tellurium vapors and excited by energy transfer from metastable oxygen O 2( a 1Δ g) in a fast-flow system. The spectrum of BiTe was found to be markedly different from those of the previously studied BiO, BiS and BiSe radicals. The A 2 4Π 1/2 → X 1 2Π 1/2 transition which forms the most prominent and extended band system in these molecules was not observed for BiTe, and the X 2 2Π 3/2 → X 1 2Π 1/2 fine structure transition shows up with a different structure and at much lower wavenumbers than in the spectra of the lighter bismuth chalcogenides. The only common feature is the C 1 4Σ − 1/2 → X 1 2Π 1/2 system which is found in the range 16 500–19 000 cm −1 similar to the three other molecules. Besides the X 2 → X 1 and C 1 → X 1 systems, seven other transitions show up by short Δ ν = 0 sequences only. With help of the data derived from the analyses of the X 2 → X 1 and C 1 → X 1 systems and theoretical predictions of electronic and vibrational energies and transition probabilities of the strongest transitions of BiTe by Lingott et al. [7] the spectra were assigned to the transitions C 1 4Σ − 1/2 → X 2 2Π 3/2, C 1 4Σ − 1/2 → A 2 4Π 1/2, A 4 4Π 1/2 → A 2 4Π 1/2, A 4 4Π 1/2 → X 2 2Π 3/2, B 1 2Π 1/2 → A 2 4Π 1/2, B 1 2Π 1/2 → A 1 4Π 3/2, and B 2 2Π 3/2 → X 2 2Π 3/2.

Synthesis, Crystal Structure, and Thermal Behavior of [BiAg3Br6(PPh3)6] and [Bi3Ag6(SPh)6Cl3(PPhiPr2)3

AbstractThe synthesis and structural characterization of two silver bismuth complexes [BiAg3Br6(PPh3)6] (1) and [Bi3Ag6(SPh)12Cl3(PPhiPr2)3] (2) is reported. Complex 1 can be obtained from the reaction of BiBr3 with AgPhCO2, PhSSiMe3, and PPh3. The reaction of bismuth(III) chloride (BiCl3) and silverbenzoate (AgPhCO2) with PhSSiMe3 in the presence of PPhiPr2 in DME leads to [Bi3Ag6(SPh)12Cl3(PPhiPr2)3] (2). The crystal structures of the compounds were determined by X‐ray analysis of single crystals, and the thermal behavior of the compounds was investigated.

Electronic states and spectra of BiS

NIR/VIS emission spectra of BiS were measured in the 5800–25 000 cm −1 region with a Fourier-transform spectrometer. BiS was produced by reaction of bismuth and sulfur vapor and excited by energy transfer from metastable oxygen O 2( a 1Δ g) in a fast-flow system. The spectrum of BiS was found to be closely related to that of the previously studied BiO radical [O. Shestakov et al., J. Mol. Spectrosc. 190 (1998) 28–77]. Five transitions connecting the Ω-components of the first three excited states, A 4Π( A 13/2, A 21/2), B 2Π( B 11/2), and C 4Σ −( C 11/2, C 23/2), with the components of the strongly split ground state, X 2Π( X 11/2, X 23/2, have been observed and analyzed.

Near-infrared electronic spectra of BiSe

NIR/VIS emission spectra of BiSe were measured in the 5800–20,000 cm −1 region with a Fourier-transform spectrometer. BiSe was produced by reaction of bismuth and selenium vapors and excited by energy transfer from metastable oxygen O 2( a 1Δ g) in a fast-flow system. The spectrum of BiSe was found to be closely related to those of the previously studied BiO and BiS radicals. Four band systems were unambiguously assigned to the transitions X 2 2Π 3/2 → X 1 2Π 1/2, A 2 4Π 1/2 → X 1 2Π 1/2, C 1 4Σ − 1/2 → X 1 2Π 1/2 and C 1 4Σ − 1/2 → A 2 4Π 1/2 and the electronic energies and vibrational constants of the states X 1 2Π 1/2, X 2 2Π 3/2, A 2 4Π 1/2 and C 1 4Σ − 1/2 were derived.

Metal–organic supramolecular assemblies generated from bismuth(III) bromide and polyimine ligands

Three new BiBr 3 supramolecular complexes, [Bi 2(3-bpdb) 2Br 8]·(3-H 2bpdb) ( 1), [Bi 2(3-Hbpdh) 2Br 8] ( 2) and [Bi 2(4-bpdh)Br 9]·3(4-Hbpdh) ( 3) {3-bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, 3-bpdh = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene and 4-bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene} were prepared by the reaction of bismuth(III) bromide with three organic nitrogen donor based ligands under thermal gradient conditions using the branched tube method. All three compounds were structurally characterized by single-crystal X-ray diffraction. In complex 1 the bismuth atoms are coordinated by one pyridyl nitrogen atom of the 3-bpdb ligand and are bridged by two bromide atoms to produce a dimeric complex. Compound 2 consists of dimeric units and the bismuth atoms are linked by one nitrogen atom of the 3-Hbpdh ligand and by five bromide atoms, and can be considered to be six-coordinate with a Br 5N array of donor atoms. The single-crystal X-ray data of compounds 1 and 3 show that the compounds contain two anionic and cationic 1D chains, [3-H 2bpdb] 2+[Bi 2(3-bpdb) 2Br 8] 2− and 3[4-Hbpdh] +[Bi 2(4-bpdh)Br 9] 3−. In all three compounds extensive hydrogen-bonding interactions produce supramolecular networks. The thermal stabilities of compounds 1–3 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA).

Near-infrared Fourier-transform and millimeterwave spectra of the BiS radical

This paper reports the 6400–7400 cm −1 Fourier-transform (FT) near-infrared (NIR) emission spectrum of the BiS X 2 2Π 3/2 → X 1 2Π 1/2 fine structure bands as well as the millimeterwave rotational spectrum of the X 1 2Π 1/2 state. For the FTNIR observations, BiS was produced by reaction of bismuth with sulfur vapor and excited by energy transfer from metastable oxygen, O 2( a 1Δ g ), in a fast-flow system. As was the case for BiO [O. Shestakov, R. Breidohr, H. Demes, K.D. Setzer, E.H. Fink, J. Mol. Spectrosc. 190 (1998) 28–77], the 0.5 cm −1resolution spectrum revealed a number of strong bands in the Δv = 0 and ±1 sequences which showed perturbed band spacings, band shapes, and intensities due to avoided crossing of the X 2 2Π 3/2 and A 1 4Π 3/2 potential curves for v ′ ⩾ 4 of X 2 2Π 3/2. The millimeterwave rotational spectrum of BiS in its X 1 2Π 1/2 state was observed when BiS was produced in a high-temperature oven by a discharge in a mixture of Bi vapor and CS 2. The signal to noise ratio was markedly improved by using a White-type multipath cell. Ninety seven features from J′ = 23.5 to J′ = 41.5 were measured between 150 and 300 GHz. Analysis of the 0.5 cm −1 resolution FT spectrum yielded the fine structure splitting and vibrational constants of the states. A simultaneous analysis of millimeterwave and a 0.005 cm −1 FT spectrum of the 0-0 band of the NIR system was carried out to give precise rotational, fine, and hyperfine constants for the X 1 2Π 1/2 and X 2 2Π 3/2 states. The results are consistent with those reported earlier for BiO and indicate only a slight decrease in the unpaired electron density in the 6p(π ∗) orbital on the Bi atom.

Synthesis and crystal structure of two new Bi(III) complexes {(Me2NCS2)3Bi}2 and {[(CH2)5NCS2]2BiI}2

Six bismuth(III) complexes containing dithio-ligands formulated as (R2NCS2)3Bi [R2NCS2M = Me2NCS2Na, C4H8NCS2Na, Bz2NCS2Na] and [(R2NCS2)2BiI]2 [R2NCS2M = C5H10NCS2Na, n Bu2NCS2Na, OC4H8NCS2Na] have been obtained by reactions of bismuth(III) halides with dithiocarbamate ligands in 1 : 2 or 1 : 3 stoichiometry. All compounds were characterized by elemental and IR analyses. The crystal structures of complexes 1 and 4 have been determined by X-ray single crystal diffraction. The structure analyses reveal that BiIII in complex 1 adopts a distorted pentagonal–pyramidal coordination, due to its stereochemically active lone pair of electrons. A long Bi · S contact of 3.218 (3) Å leads to dimeric associations of molecules in the crystal structure. The structure of complex 4 is six-coordination with a distorted octahedral configuration. Intramolecular S · S weak interactions contribute to the stability and lead to a one-dimensional chain structure.

Determination of bismuth and zinc in pharmaceuticals by first derivative UV–Visible spectrophotometry

A first order derivative spectrophotometric method has been developed for the simultaneous determination of bismuth and zinc by dithizone without time-consuming extraction step. The reactions of bismuth and zinc with dithizone in a three component solution prepared in water, acetone and n-propanol mixture have been investigated. These cations react with dithizone in this mixture at pH 5.0, forming coloured complex that is stable for at least 2 h. The linear range in D evaluation was between 3.0 × 10 −6 and 1.8 × 10 −5 mol l −1 for Zn and 2.4 × 10 −6 and 1.2 × 10 −5 mol l −1 for Bi. The limits of detection for the analytical procedure were found 0.05 mg l −1 for both cations. The relative standard deviations for the determination of 0.5 mg l −1 bismuth and 0.5 mg l −1 zinc were 1.2 and 1.1%, respectively, for five determinations. The procedure is simple, rapid and reliable. This method was applied to the determination of bismuth and zinc in the pharmaceutical materials successfully. Good agreement was achieved between the results obtained by the proposed and comparative methods.

The Cube‐Shaped Main Group Element Clusters (Bi4S4)4+ and (Bi4Se4)4+ ‐ Synthesis from Chloroaluminate Melts, Crystal Structures and Vibrational Spectra

AbstractThe reaction of bismuth and bismuth trichloride with sulfur or selenium, respectively, in a AlCl3/NaCl melt at 130 °C leads to (Bi4S4)[AlCl4]4 1 and (Bi4Se4)[AlCl4]4 2 in the form of red and amber colored crystals. Both crystallize isotypically in the tetragonal space group $I{\bar 4}$ with the lattice constants a = 1181.60(2), c = 1104.75(2) pm for 1 and a = 1199.32(2), c = 1118.64(3) pm for 2. Besides the nearly regular tetrahedral [AlCl4]‐ ions the structures contain (Bi4S4)4+ and (Bi4Se4)4+ cations. These ions are actually of crystallographic S4 symmetry but deviate only slightly from the ideal cubic symmetry. Bi and chalcogen atoms occupy alternatingly the corners of the cubes. 1 and 2 are isotypical to the already known (Bi4Te4)[AlCl4]4, so the series of the cube‐shaped (Bi4E4)4+ ions (E = S, Se, Te) is now complete. Infrared und Raman spectra of 1 und 2 show the vibration modes of both kinds of ions in the region 50 ‐ 600 cm‐1. Symmetry analysis and normal mode calculations of the vibrational spectra confirm the local symmetry of the (Bi4E4) clusters and the [AlCl4] groups.

Syntheses, crystal structures and antimicrobial activities of monomeric 8-coordinate, and dimeric and monomeric 7-coordinate bismuth(III) complexes with tridentate and pentadentate thiosemicarbazones and pentadentate semicarbazone ligands

Novel bismuth(III) complexes 1– 4 with the tridentate thiosemicarbazone ligand of 2N1S donor atoms [Hmtsc ( L1); 2-acetylpyridine ( 4 N-morpholyl thiosemicarbazone)], the pentadentate double-armed thiosemicarbazone ligand of 3N2S donor atoms [H 2dmtsc ( L3); 2,6-diacetylpyridine bis( 4 N-morpholyl thiosemicarbazone)] and the pentadentate double-armed semicarbazone ligand of 3N2O donor atoms [H 2dasc ( L4b); 2,6-diacetylpyridine bis(semicarbazone)], were prepared by reactions of bismuth(III) nitrate or bismuth(III) chloride and characterized by elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), FTIR and NMR ( 1H and 13C) spectroscopy. The crystal and molecular structures of complexes 1, 2a, 2b and 4b, and the “free” ligand L1 were determined by single-crystal X-ray structure analysis. The dimeric 7-coordinate bismuth(III) complex [Bi(dmtsc)(NO 3)] 2, 1, and the monomeric 7-coordinate complexes [Bi(Hdasc)(H 2O)](NO 3) 2 · H 2O (major product), 2a, and [Bi(dasc)(H 2O)]NO 3 · H 2O (minor product), 2b, all with pentagonal bipyramidal bismuth(III) centers, are depicted with one electron pair (6s 2) of the bismuth(III) atom, deprotonated forms of multidentate thiosemicarbazone or semicarbazone ligands, and monodentate NO 3 or H 2O ligands, respectively. These complexes are related to the positional isomers of one electron pair of the bismuth(III) atom; 1 has an electron pair positioned in the pentagonal plane (basal position), while 2a and 2b have an electron pair in the apical position. The monomeric 8-coordinate complex [Bi(mtsc) 2(NO 3)], 4b, which was obtained by slow evaporation in MeOH of the 1.5 hydrates 4a, was depicted with one electron pair of the bismuth(III) atom, two deprotonated mtsc − ligand and one nitrate ion. On the other hand, crystals of the complex “[Bi(mtsc)Cl 2]”, 3, prepared by a reaction of BiCl 3 with L1 showed several polymorphs ( 3a, 3b, 3c and 3d) due to coordination and/or solvation of dimethyl sulfoxide (DMSO) used in the crystallization. Bismuth(III) complexes 1 and 4a showed selective and effective antibacterial activities against Gram-positive bacteria. The structure–activity relationship was discussed.

Synthesis of Bis(tricarbonylcyclopentadienylmolybdenum)bismuth(III) Chloride and Its Reaction with Metals

Polynuclear organometallic compounds [CpMo(CO)3]2BiCl and [CpMo(CO)3]BiCl2 were prepared by reaction of bismuth with tricarbonylcyclopentadienylmolybdenum chloride in dimethyl sulfoxide (DMSO). [CpMo(CO)3]2BiCl is reduced with magnesium or indium in tetrahydrofuran to give bismuth, [CpMo(CO)3]3Bi, and magnesium or indium chloride. In the presence of DMSO, the reaction of [CpMo(CO)3]2BiCl with magnesium or indium yields bismuth and the organomolybdenum derivative of magnesium or lithium, respectively.

Crystal structure of a novel bismuth phthalocyanine-bismuth iodide complex

A new phthalocyaninato complex of bismuth with formula [(BiPc) 4(Bi 4I 16)] was obtained in the reaction of bismuth with 1,2-dicyanobenzene in iodine vapour. The crystal and molecular structure of the complex was determined by single crystal X-ray diffraction. The unit cell consists of four discrete (BiPc) + cations and (Bi 4I 16) 4− anions. The (Bi 4I 16) 4− complex anion is formed by four edge-sharing BiI 6 octahedra. The arrangement of molecules in the crystalline structure of the complex is mainly determined by ionic attraction between the (BiPc) + and (Bi 4I 16) 4− moieties, i.e. each (Bi 4I 16) 4− complex anion is encapsulated between four (BiPc) + cations. The structure is additionally stabilised by a set of distinct acceptor-donor intermolecular forces. The exceptionally short covalent BiN isoindole bonds are a pronounced feature of the (BiPc) + cations. To our knowledge the [(BiPc) 4(Bi 4I 16)] compound is the only example of a metallophthalocyaninato complex in which the metal atoms are not exclusively incorporated into macrocyclic Pc molecules, but occupy independent sites in the common crystalline lattice.

Coordination Compounds of Bismuth. Bismuth(III) Derivatives of Di(o-Aminophenyl)Disulfide and Diw-Tolyl)Disulfide

Bismuth metal reacts with di(o-aminophenyl)disulfide (o-H2NC6H4S)2 and di(p-tolyl)disulfide (p-MeC6H4S)2 in refluxing toluene to give the compounds Bi(SC6H4NH2-o)3 and Bi(SC6H4Me-p)3 in high yield. The reaction of bismuth with a mixture of iodine and (o-H2NC6H4S)2 or (p-Me-C6H4S)2 gives the compounds BiI2(SC6H4NH2-o)2, BiI(SC6H4Me-p)2, BiI2(SC6H4NH2-o) and BiI2(SC6H4Me-p)2. Adducts of some of the above compounds with 1,10-phenanthroline and 2,2′-bipyridyl were also prepared. The compounds and adducts were characterised by microanalyses, infrared, UV/Visible spectroscopy and conductivity measurements.

Mixed valence, tetradisordered structure of iodine-doped bismuth(III) diphthalocyanine

Tetragonal crystals of iodine-doped bismuth(III) diphthalocyanine were grown directly by the reaction of bismuth with 1,2-dicyanobenzene in the presence of I 2 at 200°C. The structure of [BiPc 2]I 1.5 shows columnar stacks of BiPc 2 units and linear chains of iodine atoms. atoms. The BiPc 2 units and doped iodine atoms are tetradisordered in the crystal. The one-dimensional iodine and pseudo one-dimensional BiPc 2 aggregates are aligned along the c-axis of the crystal. The two Pc groups in the BiPc 2 unit are staggered at an angle of 39.4° and are 3.275 Å apart. The Bi 3+ ion, eight coordinated by N-isoindole atoms, does not lie between the Pc rings at the center. The BiN distances are 2.377(8) Å to one Pc unit and 2.760(8) Å to the other. The difference of the BiN bond lengths, similar to those found in other partially oxidized M(III) diphthalocyanine complexes, correlates with the binding of the internal metal to a Pc 2− ion and to partially oxidized Pc − ion.

Isolation of a Bismuth Chloride-Iron Carbonyl Adduct: Synthesis and Structural Characterization of [PhCH(2)NMe(3)](2)[Bi(2)Cl(4)(&mgr;-Cl)(2){&mgr;-Fe(CO)(4)}

The reaction of bismuth(III) chloride with [PhCH(2)NMe(3)](2)[Fe(CO)(4)] at a ratio of 2:1 in acetonitrile yields the iron carbonyl-bismuth chloride adduct [PhCH(2)NMe(3)](2)[Bi(2)Cl(4)(&mgr;-Cl)(2){&mgr;-Fe(CO)(4)}] cleanly in high yield. The complex consists of two BiCl(3) groups bridged by an [Fe(CO)(4)](2)(-) unit. Two chloride ligands are shared between the Bi atoms, producing square-pyramidal coordination at bismuth and octahedral coordination at the iron center. The production of this complex represents the synthesis of a stable adduct of a highly nucleophilic metal carbonyl anion with a strongly Lewis acidic main group halide. The compound C(24)H(32)N(2)O(4)Bi(2)Cl(6)Fe crystallizes in the orthorhombic space group Pba2 (No. 32) with cell parameters a = 14.624(3) Å, b = 17.010(3) Å, c = 7.1990(10) Å, V = 1790.8(5) Å(3), and Z = 2.

Bismuth(III) chloride complexation with diphosphine and diarsine oxide ligands: formation and crystal structures of [BiCl3{Ph2P(O)CH2P(O)Ph2}]2 and [BiCl3{As(O)MePh2}{Ph2As(O)Ch2CH2As(O)Ph2}] n

The reactions of bismuth(III) chloride and Ph2PCH2PPh2(dppm) and Ph2AsCH2CH2AsPh2-(dpae) have been studied. The yellow products isolated initially were characterised by spectroscopic (1H and 31P NMR, IR) and microanalytical data as the 1:1 addition compounds BiCl3·dppm and BiCl3·dpae respectively. Recrystallisation of these products from boiling acetonitrile/charcoal effected oxidation of the ligands and resulted in the formation of two new molecular adducts whose structures have been determined by X-ray crystallography. Crystals of [BiCl3{Ph2P(O)CH2P(O)Ph2}]21 are triclinic, space group P with Z= 2. There are two independent centrosymmetric molecules in the unit cell with similar edge–edge shared bioctahedral structures. Each bismuth centre is six-co-ordinate with approximal octahedral geometry being bonded to two terminal chlorine atoms, two bridging chlorine atoms and two oxygen (ligand) atoms. In situ ligand oxidation dppm → Ph2P(O)CH2P(O)Ph2 occurs and the resulting bidentate (OO′) chelation gives rise to puckered six-membered [graphic omitted] ring formation. Crystals of [BiCl3{As(O)MePh2}{Ph2As(O)CH2CH2As(O)Ph2}]n2 are monoclinic, space group P21/a with Z= 4. The structure consists of one-dimensional polymeric chains. Here the in situ ligand oxidation is more complex and results in the formation of two arsine oxide ligands, viz. dpae → Ph2As(O)CH2CH2As(O)Ph2+ As(O)MePh2 both of which are involved in co-ordination to BiIII. Each bismuth atom is bonded in an approximately mer-octahedral arrangement to three terminal chlorine atoms and three oxygen (ligand) atoms. Of the latter, one is provided by a monodentate As(O)MePh2 molecule and the other two by separate Ph2As(O)CH2CH2As(O)Ph2 molecules which, by virtue of their bidentate bridging mode, are linked to adjacent metal centres.

Synthesis, Characterization and Molecular Structures of someBismuth(III) Complexes with Thiosemicarbazones andDithiocarbazonic Acid Methylester Derivatives with Activityagainst Helicobacter Pylori

The reactions of bismuth(III) nitrate pentahydrate and bismuth(III) chloride with heterocyclic thiosemicarbazones and derivatives of dithiocarbazonic acid methylester were used to synthesize the respective bismuth(III) complexes, which could be divided into five groups D-H because of their stoichiometrical properties and their molecular structures. The molecular structure and the near coordination sphere of the bismuth(III) central atom of four representative compounds were determined by single-crystal X-ray studies. Bis[1-azepanyl-4-(2-pyridyl)-2,3-diazapenta-1,3-diene-1-thiolato-N′,N3,S]bismuth(III) nitrate (5) belongs to group D. The two tridentate ligands and the nitrate ion surround the bismuth atom. The best description of the coordination sphere appears to be that of a distorted trigonal dodecahedron with one position occupied by the lone pair of the bismuth atom. Bis[1-azepanyl-4-(2-thienyl)-2,3-diazapenta-1,3-diene-1-thiolato-N3,S]bismuth(III) nitrate (9) is assigned to complex type E. Here, two deprotonated ligand molecules are coordinated to the bismuth(III) central atom as bidentate ligands. The structure of this complex can best be described as a distorted trigonal antiprism with a five-coordinated central atom. The two triangular faces are formed by the atoms S(4), N(6), O(11) and S(3), N(4) and the lone pair of the central atom. The two chelate rings are almost perpendicular to each other. Complex molecules of group F form dimeric units with bichloro-bridged bismuth atoms. The structure of di-μ-chlorobis[1-azepanyl-4-(2-pyridyl)-2,3-diazapenta-1,3-diene-1-thiolato-N′,N3,S-chloro]dibismuth(III) (15) can be described as two six-coordinated bismuth atoms, which are bound together via two bridging chlorine atoms. The two bismuth atoms Bi(1) and Bi(1a) and the two bridging chlorine atoms Cl(2) and Cl(2a) form the Bi2Cl2 plane. The two tridentate ligand molecules coordinate via the same atoms as shown in complex 5. In addition, they form two parallel planes, which are perpendicular to the Bi2Cl2 plane. With regard to the center of the Bi(1)-Bi(2) axis they are central point symmetrical, i.e. one pyridine ring lies above and the other beneath the Bi2Cl2 plane. Bismuth(III) chloride and pyridine-2-carboxaldehydethiosemicarbazone 1 b or 2-acetylpyridine-thiosemicarbazone 1 c form complexes of group G. Three chlorine atoms and a bidentate ligand are coordinated to the bismuth(III) central atom. The bidentate ligand bound to the central atom through the N(3) atom and the sulfur atom of the thioketo group. The structure of 18 is completely different from the structures of the bismuth(III) complexes discussed so far and was therefore assigned to group H. The bismuth central atom is coordinated with two ligands, which are bound in different ways. One of them is deprotonated. This ligand is bound to the central atom via the sulfur atom S(3) of the thiolate group and the N(5) atom. An interaction between the sulfur atom of the thiophene ring and the bismuth atom is not possible.The other ligand molecule is not deprotonated. This ligand is bound to the bismuth(III) cation merely via the sulfur atom S(1) of the thioketo group. The best description of the coordination sphere of the bismuth atom is that of a distorted square bipyramidal polyhedron. The square face is formed by the atoms S(3), N(5), Cl(1), the lone pair and the bismuth atom within. The axial positions are occupied by the atoms S(1) and Cl(2). The bond angle between S(1), Bi(1) and Cl(2) differs by about eight degrees from the value determined for a regular square bipyramidal polyhedron of 180 degrees. Some of the newly synthesized bismuth complexes and three ligands have been tested against several strains of Helicobacter pylori bacteria in an agar dilution test. Almost all of the listed bismuth complexes show excellent inhibitory properties with regard to growth of H. pylori already at low concentrations.

Pb-17Li-bismuth interactions: an electrical resistivity study

The reaction of bismuth with Pb-Li alloys has been studied using resistivity-composition and resistance — temperature measurements to monitor the lithium content of the alloy. The process follows a solution — precipitation mechanism. The solubility of bismuth was found to be 1.5 × 10−1 mol% (1800 wppm) in Pb-17.04Li (i.e., a Pb-Li alloy containing 17.04 mol% Li) at 723 K and 1.4 × 10−1 mol% (1800 wppm) in Pb-22.13Li at 673 K. The Li:Bi ratio in the solid product was found to be 3.07 for Pb-17.04Li, 3.21 for Pb-22.13Li and 3.28 for Pb-17.16Li, indicating Li3Bi formation. These observations are interpreted using a phase diagram developed for the Pb-Bi-Li ternary system from the phase relationships in the constituent binary systems. It is dominated by the precipitation field for Li3Bi which extends from the Bi-Li side almost as far as the Pb-Li side. The dominance of Li3Bi is attributed to its extreme stability as evidenced by both its high melting point (1418 K) and free energy of formation (ΔfG°(Li3Bi, c, 723 K) = −212.8 kJ mol−1).