Chiral synthesis of a mononuclear nickel(II) complex formed from an achiral tripodal amine ligand: spontaneous resolution.
A neutral chiral mononuclear Ni(II) complex cis-[Ni(NCS)(2)(tren)] (1) [tren = tris(2-aminoethyl)amine] has been isolated in a reaction of nickel(II) salt with an achiral ligand tren and NH(4)SCN in a MeOH-H(2)O (1:1) mixture. The crystal structure of 1 reveals the encapsulation of Ni(II) ions in a facial {NiN(6)} coordination environment that includes four nitrogen donors from the tetradentate chelate tren and two nitrogen donors from two cis-NCS (monodentate) ligands. The chirality of 1 arises from symmetry breaking of the cis-(NCS)(2)-Ni(II) octahedral complex by the tetradentate chelate tren. Compound 1 exhibits both its enantiomers in a DMF solution through a Pfeiffer effect when l- and d-arabinose are used as environment substances. The particular synthesis, described herein, offers total spontaneous resolution, as is evidenced from crystal structure and circular dichroism spectral studies.
Rao
A Srinivasa
AS
School of Chemistry, University of Hyderabad, Hyderabad 500 046, India, and Department of Chemistry, The University of Burdwan, Burdwan 713 104, India.
Pal
Abhijit
A
Ghosh
Rajarshi
R
Das
Samar K
SK