Synthesis, structure, and spectroscopic characterization of bismuth citrate compounds and bismuth-containing ulcer healing agent colloidal bismuth subcitrate (CBS). 3. Crystal and solution structures of K(NH4)[Bi2(cit)2(H2O)2](H2O)x (x = 2, 4)

Cooperative influence of thiolate ligands on the bio-relevant coordination chemistry of bismuth

“…Despite solid state characterization of a number of bismuth-citrate derivatives [20][21][22][23][24][25][26][27], analysis of the solution chemistry of these complexes is complicated by the formation of extended bismuth-oxygen networks, and solid state structures of isolated compounds are influenced by concentration and pH [4,8]. Observation of bismuth-carboxylate complexes by mass spectrometry is very rare, presumably due to labile bismuth-ligand interactions.…”

“…In select cases, complex ions are assigned with neutral amino acid ligands (e.g., [Bi(Cys)(AA) 2 À2H] + , involving the loss of two protons from two of three amino acids). Complexes containing more than one bismuth center and more than one ligand can be considered as clusters that likely involve ligand bridges between the metal centers, as observed in the solid state for many bismuth complexes [11,[20][21][22][23][24][25][26][27][28].…”

Structural characteristics of amorphous K-Bi citrate (De-Nol) and its aqueous solutions from EXAFS spectra

“…Although biologically active complexes based on Bi citrate have long been widely used in medicine, studies of the structure of the complexes have been started relatively recently [4][5][6][7][8][9][10][11]. A number of factors hinder the determination of the structure of these compounds: 1) possible variation of Bi coordination number from 3 to 10 [1]; 2) presence of other cations (potassium and/or ammonium) in the complex; 3) dependence of the compound composition on the initial solution concentration and the component ratio in it, e.g., Bi(NO 3 ) 3 and K 3 (HCit) [2,3].…”

“…A number of factors hinder the determination of the structure of these compounds: 1) possible variation of Bi coordination number from 3 to 10 [1]; 2) presence of other cations (potassium and/or ammonium) in the complex; 3) dependence of the compound composition on the initial solution concentration and the component ratio in it, e.g., Bi(NO 3 ) 3 and K 3 (HCit) [2,3]. We are aware of at least nine different crystalline forms of bismuth citrate, which were characterized by X-ray diffraction [2,[4][5][6][7][8][9][10][11]. In these compounds, the main structural element is a stable dimeric (cit 4− )BiBi(cit 4− ) moiety [4][5][6][7][9][10][11].…”

“…We are aware of at least nine different crystalline forms of bismuth citrate, which were characterized by X-ray diffraction [2,[4][5][6][7][8][9][10][11]. In these compounds, the main structural element is a stable dimeric (cit 4− )BiBi(cit 4− ) moiety [4][5][6][7][9][10][11]. Special attention should also be paid to the structural features of a crystal composed of 12-nuclear (NH 4 ) 12 10 clusters and its behavior in solutions [8].…”