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The possibility of observing a difference in the high-resolution NMR spectra of two enantiomers as due to parity nonconservation is discussed. Proposals to minimize the NMR linewidths are presented. It is concluded that, using the ultra- high-resolution technique, a difference could be observed with high Z value spin one- half nuclei such as Pt, T1, Xe. Other nuclei can also be considered. Chirality 13:699–702, 2001. © 2001 Wiley-Liss, Inc.

The possibility of observing a difference in the high‐resolution NMR spectra of two enantiomers as due to parity nonconservation is discussed. Proposals to minimize the NMR linewidths are presented. It is concluded that, using the ultra‐ high‐resolution technique, a difference could be observed with high Z value spin one‐ half nuclei such as Pt, T1, Xe. Other nuclei can also be considered. Chirality 13:699–702, 2001. © 2001 Wiley‐Liss, Inc.

The high-field EPR spectra of a mixed valence cluster compound of formula [Et3NH]2[Mn(CH3CN)4(H2O)2] [Mn10O4(biphen)4Br12] confirm that the high-spin ground state (S=12) of the cluster has a negative zero-field splitting, D=−0.037(1) cm−1. The reversal of the magnetization at low temperature should therefore overcome an energy barrier corresponding to ∣D∣S2, which corresponds to ca. 7.7 K. Slow relaxation of the magnetization is detected below 1 K by ac magnetic susceptibility and the characteristic time follows approximately an Arrhenius law, where the height of the barrier is 7.0 K. The counterion, constituted by a manganese(II) complex, is easily oxidized, and aged samples seem to contain amorphous Mn3O4.