Dinuclear Copper(II) Complexes Exhibiting Reversible Photochromism

Abstract

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 √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, H2L1, 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, H4L2, 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.

Two [Ln4] molecular rings folded as compact tetrahedra

“…The analogous ligand made with salicylaldehyde (instead of pyridinaldehyde) together its reactivity with Cu(II) was recently reported. 27 this yielded coordination complexes exhibiting reversible photochromic activity. Ligand H 2L was fully characterized (see below) and its photo-switching properties in solution were studied in ethanol.…”

“…The precursor 1,2-bis-(5carbohydrazide-2-methyl-thiophen-3-yl)-cyclopentene was synthesized according to a previously reported procedure. 27…”

Metal complexes bearing photochromic ligands: photocontrol of functions and processes

“…At the end of this section, we would like to point out the innovative approach of Aromi et al to provide DTE-light switchable qubits systems where the magnetic interaction between weakly coupled spins with long quantum coherence can be switched on and off with light. 73,74 These systems are of interest for quantum computing realizations.…”