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Molecular Parity Violation of Copper Complexes



Author(s)

Takayuki Kato

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DOI:10.17265/2161-6213/2020.5-6.002

Ashikaga University, 268-1 Ohmae Ashikaga Tochigi 326-8558, Japan

Aqua[(6-carboxyl-2-pyridilamide)histaminato]copper(II) 1 was synthesized for study of MPV (molecular parity violation). Crystal structure of 1 was defined by X-ray crystallographic analysis to give racemic structure consisting of planar-R (pR) and planar-S (pS) enantiomers. Each enantiomer was square pyramidal five coordinated copper complex with the fifth apical ligand of H₂O molecule. Specific rotation of the time development analysis of 1 gave mutarotation phenomenon from pR enantiomer priority side ([α]_D: +2,450°) to pS enantiomer priority state ([α]_D: -1,240°) in MeOH. Chiral irradiation energy of the detector from outside gave dynamic equilibrium between enantiomers, resulted to give pS enantiomer priority state with dissipative process. MPV of 1 was followed that the parity inversion of chiral restraint dz² orbital brought about inversion of chiral coordination sphere along z-axis for alternative replacement of the fifth apical ligand to solvent molecule on copper atom. SMPV (spontaneous molecular parity violation) of 1 was observed vice versa on transfiguration of specific rotation from the last pS enantiomer priority state ([α]_D: -1,240°) to pR enantiomer priority side ([α]_D: +2,450°) without chiral irradiation of optical detector, until reset analysis of the same sample. Therefore, the pR enantiomer priority state had existed in the lowest free energy of the ground state as visually unobservable SMPV state of 1 in the solvent.

MPV, SMPV, copper complex.