Dinuclear Cu(II) molecules exhibiting reversible photochromism

We present here the design and preparation of several discrete coordination complexes exhibiting two Cu(II) ions separated by a dithienylcyclopentene as a photoswitchable spacer, proposed as models of molecular root SWAP quantum gates. These models use the two Cu(II) ions as realizations of qubits and the spacer as a light switch intended to trigger the gate by reversibly undergoing a ring closing isomerization. For this, a dicarboxylate species with a central diarylethene, H(2)L1, has been used, together with bipyridine or phenantroline as capping ligands. Also, a new dinucleating ligand containing the photoactive moiety between two tridentate coordinating pockets, H(4)L2, has been designed and prepared for the same purpose. The four complexes have been characterized by single-crystal X-ray diffraction. Three of them exhibit reversible photoswitching in solution.