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Updated: Jul 28, 2026

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand
Published on: September 8, 2016
Sodium etiobilirubin-IVgamma-C10-sulfonate: a highly solvated bile pigment structure containing two different
M O Senge1, J S Ma, A F McDonagh
1Institut für Chemie, Organische Chemie, Freie Universität Berlin, Germany.
Abstract:
The crystal structure of the title compound is the first example of a bilirubin existing in both extended and cyclic conformations and the first bile pigment structure showing two markedly different conformations in the unit cell. In contrast to previous rubin structures the dipyrrinone rings are twisted out of planarity in both conformers. Because of numerous hydrogen-bonding and ionic interactions a highly complex tetrameric structure is observed in which each extended conformer is held pincer-like by another.
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