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Resolution of Seven‐Coordinate Complexes
Author(s) -
Lennartson Anders,
Vestergren Marcus,
Håkansson Mikael
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200401019
Subject(s) - enantiopure drug , crystallography , resolution (logic) , molecule , chemistry , dibenzoylmethane , crystallization , crystal (programming language) , crystal structure , supramolecular chemistry , stereochemistry , materials science , enantioselective synthesis , organic chemistry , catalysis , artificial intelligence , computer science , programming language
The crystal structures of [Pr(dbm) 3 H 2 O] ( 1 ), [Sm(dbm) 3 H 2 O] ( 2 ), and [Er(dbm) 3 H 2 O] ( 3 ) have been determined (dbm=dibenzoylmethane). They display seven‐coordinate propeller‐shaped molecules, which are chiral and crystallize as conglomerates in space group R 3. Analysis of the crystal structures reveals supramolecular interactions, including formation of a quadruple helix, which explain how stereochemical information can be transferred between stacks of molecules. A method to quantify the ee in bulk samples of stereochemically labile compounds by using solid‐state CD spectroscopy is described. Using this method, it has been shown that compounds 1 – 3 undergo total spontaneous resolution directly after synthesis, forming a microcrystalline reaction product that is essentially enantiopure. The resolution of bulk quantities of seven‐coordinate complexes (without chiral or polydentate ligands) is thus reported for the first time. Because the crystallization starts without seeding, the overall preparation may be regarded as absolute asymmetric synthesis.