Bismuth Coordination Research Articles

Coordination of bismuth and lead in porphyrins: Towards an in-situ generator for α-radiotherapy?

In order to investigate the possible coordination of both bismuth(III) and lead(II) by porphyrins for an application in alpha-radioimmunotherapy, several series of functionalized bismuth porphyrins have been synthesized and their stabilities in acidic medium were compared. Where unfunctionalized porphyrins are not suitable for such a purpose, strapped hanging carboxylate porphyrins are stable and allow a rapid coordination of both bismuth and lead. This property could lead to the preparation of an in-situ generator of alpha particles by a pre-complexation of 212lead, the radioactive parent of 212bismuth, in the ligand.

Specific interactions of Bi(III) with the Cys-Xaa-Cys unit of a peptide sequence

The medicinal application of bismuth compounds is focused in two fields: antimicrobial and anticancer. Bi(III) complexes have been used in medicine as an effective treatment of microbial infections, such as peptic ulcers, diarrhoea, gastritis and syphilis. (212)Bi and (213)Bi are strong alpha-particle emitters, which, bound to specific ligands, could be promising targeted radio-therapeutic agents for the treatment of cancer. In this work, the coordination of bismuth to three peptides with the Cys-Xaa-Cys motif was studied by potentiometric, spectroscopic, mass spectrometric and NMR methods. We have shown, that sulfur atoms from cysteines are critical donors for the coordination of Bi(III). Our investigation provides insight towards an understanding of the chemistry of bismuth-containing complexes and may lead to the further application of this metal in medicine.

Structural features of bismuth borates in the system nBi2O3-mB2O3

The crystal structures of general composition nBi2O3-mB2O3 were analyzed and systematized with the use of the structures of borate groups. Based on the CNs calculated by the bond valence method, the shapes of bismuth coordination polyhedra derived from an octahedron were suggested. A correlation was found between the number of BO3 triangles and BO4 tetrahedra in borate groups, the average CN of Bi atoms, and the degree of distortion of Bi polyhedra as a function of the m: n ratio, as well as between the polarity of BO4 tetrahedra and noncentrosymmetry of the structures. The role of Bi3+ with the active E pair in the manifestation of specific features of the forms of bismuth polyhedra and the types of connection of boron polyhedra was elucidated.

One-dimensional inorganic arrangement in the bismuth oxalate hydroxide Bi(C 2O 4)OH

Single crystals of Bi(C 2O 4)OH were obtained by the slow diffusion of Bi 3+ cations through silica gel impregnated with oxalic acid. The structure was solved in the Pnma space group with a=6.0853(2) Å, b=11.4479(3) Å, c=5.9722(2) Å, leading to R=0.0188 and w R=0.0190 from 513 unique reflections. The bismuth coordination polyhedron is a BiO 6E pentagonal bipyramid with the lone pair E sitting at an axial vertex. The opposite axial vertex is occupied by a hydroxyl oxygen atom, which is also an equatorial corner of a neighboring BiO 6E bipyramid. The sharing of the hydroxyl oxygen atoms build ∞ 1 [ BiO 5 E ] zig-zag chains running down the [100] direction. These chains are aligned in a sheet parallel to the (010) plane and are further connected through oxalate ions to form a three-dimensional arrangement. On heating, Bi(C 2O 4)OH decomposes to the meta-stable quadratic β-Bi 2O 3 phase.

Hydrothermal synthesis and characteristics of 3-D hydrated bismuth oxalate coordination polymers with open-channel structure

Two new 3-D porous bismuth coordination polymers, (C 5NH 6) 2[Bi 2(H 2O) 2(C 2O 4) 4]·2H 2O 1 and (NH 4)[Bi(C 2O 4) 2]·3H 2O 2, have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic symmetry, P2 1/ c space group with a=10.378(2) Å, b=17.285(3) Å, c=16.563(5) Å, α=90°, β=119.66(2)°, γ=90°, V=2581.8(10) Å 3, Z=4, R 1=0.0355 and w R 2=0.0658 for unique 4713 reflections I >2 σ( I). Compound 2 crystallizes in the tetragonal symmetry, I4 1/ amd space group with a=11.7026(17) Å, b=11.7026(17) Å, c=9.2233(18) Å, α=90°, β=90°, γ=90°, V=1263.1(4) Å 3, Z=32, R 1=0.0208 and w R 2=0.0518 for unique 359 reflections I> 2 σ( I). Compounds 1 and 2 are 3-D open-framework structures with a 6 6 uniform net, which consist of honeycomb-like layers connected to each other by oxalate units. While different guest molecules fill in their cavities of honeycomb-like layers, study of ultrasonic treatment on 2 indicates the replacement of NH 4 + by K + on potassium ion exchange. Thermogravimetric analysis indicates that the open-channel frameworks are thermally stable up to 200 °C, and other characterizations are also described by elemental analysis, IR and ultraviolet–visible diffuse reflectionintegral spectrum (UV–Vis DRIS).

Structural and Coordination Studies of “Pearl Oysterlike” Porphyrins

We report the coordination studies of porphyrins with pre-organized but yet flexible straps, each bearing over the center of the porphyrin either a 2,2-malonic acid diethyl ester residue or a 2,2-malonic acid residue. The straps are attached to the porphyrin via two adjacent meso positions, 5,10 and 15,20, respectively, and the 2,2-malonic acid diethyl ester groups are connected to the straps on benzylic carbon atoms. These two structural features allow a significant flexibility of the straps, as confirmed by the comparison of the X-ray structures of the zinc, nickel, and lead complexes of porphyrin 1. In the latter, the influence of the lone-electron pair of lead is clearly demonstrated. The coordination of bismuth is also reported.

The coordination of bismuth by porphyrins

The coordination chemistry of porphyrins towards the complexation of bimuth(III) has been investigated. Although the insertion of bismuth is tedious in porphyrins such as octa-ethyl porphyrin (OEP) or tetra-tolyl porphyrin (TTP), we have demonstrated that simple modifications of the ligand, like the grafting of arms bearing either ester groups or acid functions, lead to stable complexes, resulting from a rapid complexation reaction. La coordination du bismuth(III) par les porphyrines a été étudiée. Bien que l'insertion du bismuth soit réalisée difficilement dans des porphyrines telles que l'octa-éthylporphyrine (OEP) ou la meso-tétra-tolylporphyrine (TTP), nous avons pu montrer que de simples modifications du ligand, telles que le greffage d'un bras portant des fonctions ester ou acides, conduit à des complexes stables, résultant d'une réaction de complexation rapide.

Linear and Pre-organized Carboxylic Acid Picket Porphyrins as Bismuth Chelators

New picket porphyrins delivering at least one carboxylic group around the coordination site of the macrocycle were synthesized for bismuth coordination. The influence of the number, the length, and the pre-organization of the carboxylic acid pickets on the stability of the bismuth complexes was explored. Their stabilities in acidic medium were compared with those of their precursors bearing ester pickets. The molecular structure of one of the bismuth complexes, which is the only monomeric bismuth porphyrin reported up to now, is discussed. At the opposite of what we initially reported, and in agreement with the theoretical calculations, the distortion of the macrocycle in this structure is mainly due to the number of water molecules in the first sphere of coordination of the bismuth.

Crystal growth and elastic properties of orthorhombicBi2Ga4O9

The combination of favourable oxygen conductivity at high temperatures with mechanicalstrength make Bi-containing compounds with mullite-type crystal structures strongcandidates for use as electrolytes of solid fuel cells. Large single crystals of orthorhombicBi2Ga4O9 with dimensionsup to 20 × 20 × 10 mm3 were grown by the top-seeded solution growth technique. Their elastic constants at room temperaturewere determined for the first time using resonant ultrasound spectroscopy. The values given in GPaare c11 = 143.4(2), c22 = 161.7(2), c33 = 224.2(3), c44 = 69.6(1), c55 = 49.2(1), c66 = 76.5(2), c12 = 73.7(2), c13 = 62.2(3) and c23 = 70.3(3). Further, the crystal structure and the elastic properties ofBi2Ga4O9 were studied at 0 K by parameter-free ab initio calculations based on density-functionaltheory. On average the computed elastic constants differ from the experimental values byabout 10%, indicating the reliability of the theoretical approach. Like in othermullite-type compounds the anisotropy of the longitudinal elastic stiffness is clearlycontrolled by the structurally dominant octahedral chains running parallel to [001].The deviations from Cauchy relations show a significant anisotropy of the typeg22>g11≈g33 which is related to the covalent character of the bonding interactions within the infinite–Bi–O–Bi–O– bond chains parallel to [010]. The mean elastic stiffness ofBi2Ga4O9 is about 40%smaller than for 2/1-mullite and sillimanite. This discrepancy can be attributed to the mechanically very soft behaviour ofthe Bi 6s2 lone electron pair. Its stereochemical activity is clearly evident from both the asymmetry ofthe bismuth coordination polyhedron and the calculated electron density maps.

Glass Network Evolution with Bi3+/Ti4+ Substitution in Phosphate Glasses Formulated with a Constant Oxygen/Phosphorus Ratio. EXAFS, XANES, and 31P Double Quantum MAS NMR

This paper reports a structural study of the effect of TiO2 substitution for Bi2O3 in xNa2O−xP2O5−yBi2O3−zTiO2 glasses, which were formulated in order to keep a constant average polymerization of the phosphate network. XANES and EXAFS analyses have indicated that the bismuth coordination sphere is similar to that described in other phosphate glasses [Daviero S.; Montagne L.; Palavit G.; Mairesse G.; Belin S.; Briois V. J. Phys. Chem. Solids 2003, 64 (2), 253], and that the titanium coordination sphere is asymmetric, but remains octahedral whatever the substitution degree. 31P double-quantum filtered MAS NMR shows that the Q2 fraction increases with the titanium content in the glasses, thus revealing a repolymerization of the phosphate network. The consideration of charges on oxygens (in terms of valence units) leads to the conclusion that titanium octahedra are coordinated to both Q1 and Q2 sites. The excess charge on these oxygens is compensated by Na+ removed from Q1 sites, which explains the observed repolymerization of the phosphate network. The evolution of glass properties is discussed within the context of this structural model. The increase of glass-transition temperature with titanium substitution for bismuth is due to the repolymerization of the phosphate network. The increase of electrical conductivity with titanium content is attributed to an increase of sodium mobility when it is involved in charge compensation of Ti4+ octahedra.

A generally applicable synthetic approach for heteroleptic thiolate complexes of bismuth

As part of a systematic development of bismuth coordination chemistry, we are exploiting the thermodynamic and hydrolytic stability of Bi—S bonds. A series of heteroleptic thiolate bismuth complexes have been isolated and characterized. The generally applicable synthetic methodology involves the use of hetero-bifunctional ligands containing a thiolate moiety as an anchor to facilitate coordinate interaction of weak donors (carbonyls, amines, hydroxyls) with bismuth. The bifunctional nature of the ligands is manifested in chelating roles. Important comparisons with established thiolate complexes of bismuth are discussed.Key words: bismuth, thiolate, heteroleptic, crystallography.

Synthesis and Study of Heterometallic Co–Bi Compounds Based on Ethylenediaminetetraacetic Acid. Crystal and Molecular Structures of [Co(DH)2(o-NH2C6H4CH3)2]2[Bi2(μ-Edta)2(H2O)2] · 10H2O (DH2 is dimethylglyoxime)

Compounds of the [Co(DH)2A2](BiEdta) · 6H2O type (where DH is the monodeprotonated dimethylglyoxime –ON=C(CH3)–(CH3)C=NOH; A is the o-, m-, or p-toluidine; and Edta is the ethylenediaminetetraacetate(4–) ion) were synthesized and studied. The composition and structures of the complexes were determined from their UV and 1H NMR spectra and from X-ray diffraction data. The isomer [Co(DH)2(o-NH2C6H4CH3)2]2[Bi2(μ-Edta)2(H2O)2] · 10H2O was structurally characterized using X-ray diffraction analysis. The crystals are triclinic: a = 12.153(2) A, b = 12.824(3) A, c = 16.215(3) A, α = 67.73(3)°, β = 86.18(3)°, γ = 66.96(3)°, space group P\(\overline 1\), ρ(calcd) = 1.719 g/cm3, Z = 4. The structure is composed of complex binuclear [Bi2(μ-Edta)2(H2O)2]2– anions, [Co(DH)2(o-NH2C6H4CH3)2]+ cations, and molecules of crystallization water. The Edta4– anion chelates with the Bi atom in a hexadentate manner (N2O4); the fifth O atom functions as a bridging ligand. The bismuth coordination polyhedron can be regarded as a strongly distorted antiprism. In the octahedral cation, the Co(III) atom coordinates four N atoms of two DH ligands (average Co–N 1.897 A) and two N atoms of two o-toluidine molecules (Co–N 2.023 A). Thermolysis of the complexes studied was found to proceed in several successive steps, namely, the deaquation, deamination, and pyrolysis of the ligands.

Bismuth(III) coordination compounds. Synthesis, characterization, and X-ray structures of [Bi(Cl)(μ-Cl) 2(THF) 2] ∞, Bi(O 2CMe) 3(Solv) x (Solv = py, x = 2 or MeIm, x = 4) [1], and [Bi(μ-OCH 2CMe 3)(OCH 2CMe 3) 2(Solv)] 2 (Solv = HOCH 2CMe 3 or py)

We have isolated and structurally characterized several novel bismuth coordination compounds. Dissolution of Bi(NO 3) 3 · 5H 2O in concentrated HCl, followed by crystallization from THF lead to the isolation of [Bi(Cl)(μ-Cl) 2(THF 2] ∞ 1. Each bismuth metal center of 1 adopts a 7-coordinated pentagonal bipyramidal geometry. One THF solvent molecule and one terminal chloride ligand are located in each of the axial positions. A terminal THF solvent molecule and four bridging chlorides reside in the equatorial positions. Dissolution of Bi(O 2CMe) 3 in pyridine (py) or N-methylimidazole (MeIm) results in the isolation of the appropriate amine adduct, either Bi(O 2CMe) 3(py) 2, 2 or Bi(O 2CMe) 3(MeIm) 3 · (MeIm), 3. Compound 2 uses two py molecules to adopt an unusual (for bismuth acetate species) 8-coordinated triangular dodecahedral geometry. In contrast, 3 incorporates three MeIm molecules to adopt the 9-coordinated tricapped trigonal prismatic geometry typically observed for bismuth acetate compounds (a “free” MeIm molecule is located in the lattice). The reaction of Bi[N(SiMe 3) 2] 3 with HOCH 2CMe 3 (HONp) yields [Bi(μ-ONp)(ONp) 2(HONp)] 2, 4. An alternative synthetic route to 4 is the metathical exchange between BiCl 3 and 3 equivalents of NaONp in the presence of HONp. The bismuth atoms of 4 are 5-coordinated and adopt an apical-shared, square base pyramidal (SP) arrangement. Recrystallization of 4 from py yields the dinuclear complex [Bi(μ-ONp)(ONp) 2(py)] 2, 5. The Bi atoms of 5 also adopt a 5-coordinated SP geometry; however, the two metal centers are linked through a basal-shared arrangement. The apical ONp ligands are in an up-down relationship to each other.

Preparation and Crystal Structure of the Titanium and Hafnium Bismuthides Ti8Bi9and Hf8Bi9

The titanium bismuthide Ti8Bi9has been prepared by reaction of the elemental components in evacuated, sealed silica tubes and also by arc-melting. Its crystal structure is of a new type, which was determined from single-crystal X-ray data:P4/nmm,a=1027.7(1) pm,c=737.5(1) pm,Z=2,R=0.027 for 553 structure factors and 32 variable parameters. The titanium atoms occupy four different sites: two with octahedral and two with square-antiprismatic bismuth coordination. The bismuth atoms are located at three different sites with four, five, and seven titanium neighbors. An analysis of the Ti–Bi bonding distances (covering the range between 282 and 314 pm) leads to the conclusion that there are Ti–Ti bonding interactions (at distances between 293 and 307 pm). In addition, some weakly bonding Bi–Bi interactions (334–353 pm) are assumed. The compound Hf8Bi9has the same structure:a=1071.8(1) pm,c=752.0(1) pm.

Neutron Diffraction Study of the Nonmodulated 2212-Type Cuprate Bi1.5Ba2.5LaCu2O8.25

The structure of the nonmodulated bismuth cuprate Bi1.5Ba2.5La Cu2O8.25 has been determined from powder neutron diffraction data. This phase crystallizes in the space group I4/mmm, with a = 3.9322(1) and c = 31.240(1) Å. The significant features are: (i) the puckering of the [CuO2]∞ layers due to the fact that copper is located out of the basal plane of the CuO5 pyramid, (ii) the location of barium in the bismuth bilayers, whereas lanthanum occupies entirely the fluorite-type cages between the copper layers, and (iii) the complex structure of the [Bi1.5Ba0.5O2.25]∞ layers. In the latter layers barium and bismuth are located in two distinct (4e) sites, the majority of the oxygen atoms are located at the same level as bismuth, forming flat layers, and their positions correspond to a splitting with respect to the ideal one. The excess oxygen appears to be located between the double bismuth layers. The coordination of bismuth and barium is also discussed.

Crystal chemical principles of selective synthesis of bismuth-containing phases with perovskite-like structures

Bismuth-containing phases with perovskite-like structures were systematized and assigned to 11 homologous series. For two phases differing in bismuth coordination, Bi2A k ′ A 2 ″ Cuk+1Ox and Bi2A k ′ Cuk+1Ox, crystallochemical principles of their formation are defined. The range of existence of these phases was found and confirmed by syntheses.

An oxygen deficient fluorite with a tunnel structure: Bi 8La 10O 27

A new lanthanum bismuth oxide, Bi 8La 10O 27, has been synthesized. It crystallizes in the Immm space group with the following parameters: a = 12.079 (2) Å, b = 16.348 (4) Å, c = 4.0988 (5) Å. Its structure was determined from powder X-ray and neutron diffraction data. It can be described as an oxygen deficient fluorite superstructure ( a ≈ 3a F √2 , b ≈ 3a F , c ≈ a F √2 ) in which bismuth and lanthanum, as well as oxygen vacancies, are ordered. The structure consists of fully occupied (110) or ( 110) lanthanum planes (La) which alternate with mixed { Bi La } planes and fully occupied oxygen planes ( A) which alternate with two sorts of oxygen deficient (110) or ( 110) planes ( B and C) according to the sequence -[ La A B { Bi La } C C { Bi La } B A [- . The anionic distribution determines tunnels where the bismuth ions are located, forming diamond-shaped based tunnels. The coordination of bismuth and lanthanum is discussed. The high thermal factor of some oxygen atoms suggests that this oxide exhibits ionic conductivity.

ChemInform Abstract: Ca4Bi6O13, a Compound Containing an Unusually Low Bismuth Coordination Number and Short Bi···Bi Contacts.

AbstractThe title compound, prepared by heat treatments of a CaCO3/Bi2O3 mixture in the range 700‐900 °C, crystallizes in the orthorhombic space group C2mm with Z=2.

On the coordination of bismuth in Bi2CaSr2Cu2O8 - A2aa/Amaa structures revisited

Abstract A re-examination of the profile refinement of the neutron data of Bi 2 CaSr 2 Cu 2 O 8 according to A2aa/Amaa structures leads to new and unusual features in the coordination of Bi. Our analysis points to the formation of closely packed near-linear BiO 2 moieties stacked parallel to the a -axis with unusually short contacts between oxygens of neighbouring BiO 2 groups.

CH3C6H5BiCl2][AlCl4] and [(CH3)6C6BiCl2] [AlCl4]–Compounds containing η6‐Arene‐Complexed BiCl Units

The ability of AlCl3 to abstract chloride ions from BiCl3 makes it possible to synthesize the title compounds in the presence of toluene and hexamethyl benzene, respectively. 1, the hexamethylbenzene complex, is an arene‐stabilized, dimeric dichlorobismuth(III) tetrachloroaluminate. The coordination of bismuth can be described as strongly distorted octahedral; five Cl ligands (two shorter, three longer Bi–Cl distances), one arene ligand. equation image