A proposed novel structure for the metal chelates of bilirubin

Luminescent sensing film based on sulfosalicylic acid modified Tb(III)-doped yttrium hydroxide nanosheets

“…Figure 11(a) shows the UV spectra of nanosheets, nanosheets-BR, SSA, SSA-BR, and BR, revealing that the position of the BR absorption peak (440 nm) is not affected by the presence of SSA, which indicates the absence of BR-SSA coordination. However, the above peak shifts from 440 to 411 nm after mixing with nanosheets, in agreement with the known ability of BR to coordinate rare-earth ions [44][45][46]. The emission peak of SSA located at 402 nm [47,48] significantly overlaps with the absorption peak of coordinated BR (411 nm), which results in luminescence quenching.…”

Metal complexes of bilirubin in aprotic solvents

“…or other metal ions have been observed in solution (O'Carra, 1962;Velapoldi & Menis, 1971), and a spectrophotometric investigation of bilirubin-samarium acetate complexes has been described (Kuenzle et al, 1972). We now report the formation of stable complexes between bilirubin and zinc salts ofaliphatic acids in dipolar aprotic solvents.…”

Bilirubin Metabolism and its Disorders

“…46 Despite the presence of two propionic acid side chains, four amino groups, and two lactam oxygens, bilirubin IX is insoluble in water at physiologic pH. A possible explanation for this paradox was suggested by Fog and Jellum 47 and Kuenzle et al, 48,49 who proposed that bilirubin IXa may be internally stabilized by hydrogen bonding between the carboxyl and the two external pyrrolenone rings ( Figure 74-2). X-ray diffraction studies of crystalline bilirubin confirm hydrogen bonding between each propionic acid side chain and the pyrrolic and lactam sites in the opposite half of the molecule.…”