Tricarbonyl Mono- and Dinuclear Rhenium(I) Complexes with Redox-Active Bis(pyrazole)–Tetrathiafulvalene Ligands: Syntheses, Crystal Structures, and Properties

Abstract

Two new bis(3,5-dimethylpyrazole)-substituted tetrathiafulvalene ligands, 2,6(7)-bis(methylthio)-3,7(6)-bis(3sulfanyl-3,5-dimethylpyrazole)tetrathiafulvalene (L 1 ) and 2,3-bis(methylthio)-6,7-bis(3-sulfanyl-3,5-dimethylpyrazole)tetrathiafulvalene (L 2 ), have been prepared and characterized. On the basis of the two ligands, three interesting rhenium(I) tricarbonyl mono-or dinuclear complexes, ClRe(CO) 3 (cis-L 1 ) (1), [ClRe(CO) 3 (trans-L 1 )] 2 (2), and [ClRe(CO) 3 (L 2 )] 2 (3), have been prepared and structurally characterized. Electrochemical studies show sequential oxidation processes of the compounds to the corresponding radical cation and dication states, suggesting that redox events are essentially dependent on the structures of the rhenium(I) complexes. The results have evidenced electronic interactions between the TTF cores in complexes 1 and 2. Geometric and electronic structures as well as the spectroscopic properties for complexes 1−3 have been investigated by using DFT and TDDFT calculations.

Metal-driven self-assembly: the case of redox-active discrete architectures

“…8a). 27 The latter was obtained in one step by the reaction of a mixture of cis and trans bis(pyrazole)-TTF ligands with Re(CO) 5 Cl. Their XRD analysis revealed that the TTF skeleton is bended in 15 and planar in metalla-ring 16.…”

A Self-Assembled Electro-Active M8L4 Cage Based on Tetrathiafulvalene Ligands

“…In this context, very few examples of coordination-driven redox-active self-assembled discrete structures have been described so far. Their constituting ligands are usually based on electro-deficient skeletons such as triazine [ 17 , 18 ] or perylene diimide [ 19 – 25 ] units and more rarely on oxidable fragments [ 26 , 27 ]. It has to be noted that the electro-activity can also be located on the metal complex [ 28 – 38 ] or on pendant units [ 39 – 43 ] instead of being centered on the side-walls.…”

Coordination assemblies based on a flexible tetrathiafulvalene derivative

“…This type of macrocyclic assembly has been observed with other TTF derivatives bearing peripheral nitrile, phosphine, pyrazole or pyridine moieties. [34][35][36][37][38][39] In particular, it is worth noting that a [2+1] metallamacrocycle has been described upon assembly of Co(hfac)2 (hfac = hexafluoroacetylacetonate) with an analogue of 1 incorporating a 2-pyridyl group and the longer ethylene spacer. [34] In this case, however, coordination of the metal cations involved the two binding units at the periphery of the same dithiol ring.…”