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Supramolecular Ammine‐Copper rac ‐BINOLAT Salts through in‐situ R ‐ or S ‐BINOL Racemization
Author(s) -
Wisser Barbara,
Labahn Andreas,
Näther Christian,
Janiak Christoph
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000005
Subject(s) - racemization , chemistry , supramolecular chemistry , moiety , deprotonation , copper , enantiomer , crystallography , hydrogen bond , stereochemistry , racemic mixture , molecule , medicinal chemistry , crystal structure , ion , organic chemistry
The molecule rac ‐1,1'‐binaphthalene‐2,2'‐diol ( rac ‐1,1'‐bi‐2‐naphthol, rac ‐BINOL) shows a propensity for supramolecular, charge‐assisted O–H ··· O – hydrogen‐bonded strand formation when crystallized with its deprotonated form BINOLAT 2– and Cu 2+ in conc. ammonia. The naphthyl‐paneled cavities in the {( rac ‐BINOLAT 2– )( rac ‐BINOL) 2 } strands host the [Cu(NH 3 ) 5 ] 2+ ‐guest cation through second‐sphere N–H ··· O hydrogen bonding in the structure of [Cu(NH 3 ) 5 ] 2+ ( rac ‐BINOLAT 2– )( rac ‐BINOL) 2 . Decreasing the copper(II) and ammonia concentrations in the crystallization leads to {( rac ‐BINOLAT 2– )( rac ‐BINOL)} strands, in which rac ‐BINOLAT 2– coordinates to two copper(II) atoms in the structure of [Cu(NH 3 ) 2 (μ‐ rac ‐BINOLAT 2– ‐κ 2 O,O' :κ O )] 2 ( rac ‐BINOL) 2 . In the {Cu 2+ (NH 3 ) 2 } moiety two BINOLAT‐oxide atoms act as bridging ligands. Both copper structures could be obtained by using the racemic rac ‐BINOL or the enantiomeric R ‐ or S ‐BINOL, through an in‐situ racemization of the latter.