RESUMEN
Inspired by the cubic Mn4 CaO5 cluster of natural oxygen-evolving complex in Photosystem II, tetrametallic molecular water oxidation catalysts, especially M4 O4 cubane-like clusters (M=transition metals), have aroused great interest in developing highly active and robust catalysts for water oxidation. Among these M4 O4 clusters, however, copper-based molecular catalysts are poorly understood. Now, bio-inspired Cu4 O4 cubanes are presented as effective molecular catalysts for electrocatalytic water oxidation in aqueous solution (pHâ 12). The exceptional catalytic activity is manifested with a turnover frequency (TOF) of 267â s-1 for [(LGly -Cu)4 ] at 1.70â V and 105â s-1 for [(LGlu -Cu)4 ] at 1.56â V. Electrochemical and spectroscopic study revealed a successive two-electron transfer process in the Cu4 O4 cubanes to form high-valent CuIII and CuIII O. intermediates during the catalysis.
RESUMEN
Irradiation of (2R,4R)-(-)- and (2S,4S)-(+)-2,4-pentanediyl-bis-2-naphthoates (1R and 1S, respectively) in organic solutions exclusively results in cubane-like anti(HH) photodimers in 100% yield. Asymmetric induction with 100% diastereometric excess (de) has been achieved and the absolute configuration of the yielded diastereomers has been established. Moreover, irradiation of (2R,4S)-2,4-pentanediyl-bis-2-naphthoate (1M) gives cubane-like syn(HH) photodimers in 100% yield.
RESUMEN
Irradiation of 2-naphthalenecarbonitrile (2-NpCN) in solution with a light lambda > 280 nm results in the formation of three rigid cubane-like photodimers, anti-head-to-head 1, anti-head-to-tail 2, and syn-head-to-tail 3, which are not in line with the previously recognized regioselectivity. These cubane-like photodimers have been well characterized by spectroscopic investigation and/or X-ray crystal structural analysis in this work. Moreover, the separation of the optically pure enantiomers of 1, 2, and 3 has been achieved by HPLC resolution.