Electronic Interplay between TTF and Extended-TCNQ Electrophores along a Ruthenium Bis(acetylide) Linker

Abstract

A bis(TTF-butadiynyl) ruthenium D-D'-D complex, with intramolecular electronic interplay between the three electron-donating electrophores, was easily converted through a cycloaddition-retroelectrocyclization with TCNQ into a D-A-D'-A-D pentad complex, which exhibits an intense intramolecular charge transfer together with an electronic interplay between the two acceptors along the conjugated organometallic bridge.

Metal (Hg, Pt, Ru) Bisalkynyl Bridge between Tetrathiafulvalene Electrophores and Electronic Interplay

“…166.84 • and 178.25 • respectively. It is interesting to compare the bond lengths of the butadiyne rod with those observed in the starting TTFs and the previously reported complex with two TTFs, namely trans-[Ru(-C≡C-C≡C-Me 3 TTF) 2 (dppe) 2 ], (Table 2) [28]. Within the mono-TTF substituted complex, the bond lengths for the butadiyne rod indicate a high degree of conjugation compared to the TTF precursors 2 and 4.…”

“…This indicates that the Ru bis(acetylide) linker is the only organometallic linker which allows the formation of mixed valence species (TTF/TTF +• and TTF +• /TTF 2+ ) within the series [16]. On the other hand, the introduction of a Ru bis(butadiyne) spacer group does not allow the observation of electronic interplay on the first redox process between the two TTF cores but only on the second redox process [28]. This redox behavior is uncommon in the case of TTF dimers and could be tentatively assigned to electrostatic repulsion generated in the TTF +• /TTF 2+ species, as previously observed for the oxidation of the TTF moieties in their dicationic states for the trans-[Ru(C≡CMe 3 TTF) 2 (dppe) 2 ] [16].…”

“…Therefore, we investigated the synthesis of a complex where the mercury was linked to two TTF units via such an alkynyl linkage and we describe here this bis(acetylide) mercury complex, trans-[Hg(C≡CMe 3 TTF) 2 ] (Chart 1). We also recently reported the effect of the length of the conjugated linker between the TTF core and the Ru center by replacing the ethyne linker with a butadiyne rod [28]. This structural modification between the Ru and the two TTFs still allows for an electronic interplay between the three electrophores however, with weaker interactions, such as in the trimetallic complexes with ferrocene electrophore in trans-[Ru(C≡C-C≡CFc) 2 (dppe) 2 ] vs. trans-[Ru(C≡CFc) 2 (dppe) 2 ] [29].…”

Charge‐Transfer Salts of 6,6‐Dicyanopentafulvenes: From Topology to Charge Separation in Solution

“…We describe the solid‐state structures of 1⋅ Cp 2 Co and 2⋅ Fc* and investigate the magnetic properties of these CT compounds by means of EPR and UV/Vis spectroscopy and superconducting quantum interference device (SQUID) measurements. In view of the rather subtle response of CT‐based materials on even minor topological changes, we show that it is essential to discern between the crystalline states and their frozen and fluid solutions.…”

“…[1] The field of organic materialsb ased on CT has grown substantially. [2,3] It is also well establishedt hat redox-active organometallic-based donors, such as metallocenes, readily form CT complexes with organic acceptors. [4][5][6][7][8][9][10][11] A crucial prerequisitef or the utilization of CT systems in devices is sufficient robustness.W eh ave embarked on new cyano-rich organic acceptors,6 ,6-dicyanopentafulvenes (DCFs), displaying uniquer eactivity.…”