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Chiral Recognition of Racemic Proline based on Chiral Macrocyclic Nickel(II) Complex: Synthesis and Crystal Structures
Author(s) -
Li HuanYong,
Jia GuoKai,
Zeng Fei,
Tang ShanShan,
Ou GuangChuan
Publication year - 2018
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.201800043
Subject(s) - chemistry , nickel , enantiomer , crystal structure , crystallography , acetonitrile , supramolecular chemistry , stereochemistry , octahedron , carboxylate , hydrogen bond , proline , octahedral molecular geometry , monomer , molecule , amino acid , polymer , organic chemistry , biochemistry
The reactions of dl ‐proline with chiral macrocyclic Ni II complex [Ni( SS ‐ L )](ClO 4 ) 2 in acetonitrile/water gave a six‐coordinate enantiomer formulated as [Ni( SS ‐ L )( l ‐Pro)](ClO 4 ) 2 · H 2 O ( 1 ). Another enantiomer of [Ni( RR ‐L)( d ‐Pro)](ClO 4 ) 2 · H 2 O ( 2 ) was obtained when [Ni( RR‐ L)](ClO 4 ) 2 was used (L = 5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, Pro = proline). Single‐crystal X‐ray diffraction analyses of complexes 1 and 2 revealed that the Ni II atom has a distorted octahedral coordination arrangement, being coordinated by four nitrogen atoms of L in a folded configuration, plus two carboxylate oxygen atoms of proline in mutually cis positions. Complexes 1 and 2 are supramolecular stereoisomers, which are constructed with hydrogen bonding linking of [Ni( SS ‐L)( l ‐Pro)] 2+ and [Ni( RR ‐L)( d ‐Pro)] 2+ monomers to form one‐dimensional zigzag chains. The homochiral natures of complexes 1 and 2 were confirmed by solid CD spectroscopy.