A Photoswitchable Metallocycle Based on Azobenzene: Synthesis, Characterization, and Ultrafast Dynamics.

The novel photoswitchable ligand 3,3'-Azobenz(metPA) (1) is used to prepare a [Cu(1)](BF) metallocycle (2), whose photoisomerization was characterized using static and time-resolved spectroscopic methods. Optical studies demonstrate the highly quantitative and reproducible photoinduced cyclic E/Z switching without decay of the complex. Accordingly and best to our knowledge, [Cu(1)](BF) constitutes the first reversibly photoswitchable (3d)-metallocycle based on azobenzene.

Cooperativity-Driven Reactivity of a Dinuclear Copper Dimethylglyoxime Complex.

In this report, we present the dinuclear copper(II) dimethylglyoxime (H dmg) complex [Cu (H dmg)(Hdmg)(dmg)] (1), which, in contrast to its mononuclear analogue [Cu(Hdmg) ] (2), is subject to a cooperativity-driven hydrolysis. The combined Lewis acidity of both copper centers increases the electrophilicity of the carbon atom in the bridging μ -O-N=C-group of H dmg and thus, facilitates the nucleophilic attack of H O. This hydrolysis yields butane-2,3-dione monoxime (3) and NH OH that, depending on the solvent, is then either oxidized or reduced.