Alkynyl cobalt complexes. An electrochemical study

Synthesis, structures and comparative electrochemical study of 2,5-bis(trimethylsilylethynyl)thiophene coordinated cobalt carbonyl units

“…The interest in this kind of complexes is due, in part, to the stabilising influence of the metal on reactive unsaturated carbon chains and polycarbon ligands [1,2] and, on the other hand, to their potential optoelectronic properties as non-linear optical and electroluminescent materials [3], or as ''molecular'' wires [4,5]. Thus alkynyl or polyynediyl bridging ligands have been shown to be especially efficient in allowing the passage of electronic effects between redox active centres [6][7][8] and therefore the electronic properties can be modified by changing both, metal fragments and/or alkyne ligands [9]. The electronic communication through such potential molecular wires is often evaluated by studying the redox response of electroactive groups [10].…”

Synthesis, crystallographic and electrochemical study of ethynyl[2.2]paracyclophane-derived cobalt metallatetrahedranes

“…6). Overall, the electrochemical behaviour of 2 is similar to those of related hexacarbonyl complexes Co 2 (CO) 6 (alkyne) (alkyne ¼ alkynylthiophene, butadiyne) [2b, 12,18]. The oxidation and reduction mechanisms described above are summarized in Scheme 3.…”

“…The radical anion 2 À formed during this chemical process is rapidly decomposed into a variety of fragments, including the [Co(CO) 4 ] À anion due to metalemetal bond cleavage [12,18].…”

“…Electrochemical data reported for other Co 2 (CO) 6 (alkyne) (alkyne ¼ alkynylthiophene, butadiyne) complexes indicated that chemical reversibility could be gradually achieved when the temperature is decreased [2b, 12,18]. Indeed, around À40 C, Scheme 2.…”

Synthesis, Structure and Electrochemical Properties of Triarylamine Bridged Dicobaltdicarbon Tetrahedrane Clusters

“…This simple reaction sequence, coupled with the capacity to readily tune the electrochemical behaviour of the resulting Co 2 C 2 clusters through ligand substitution reactions and relatively simple IR (CO) spectra has led to several investigations of the redox chemistry and electron transfer behaviour in ligand bridged species based on these moieties [43][44][45]. For example, following initial electrochemical studies by Osella [46], the Otago group have used a combination of electrochemical and spectroelectrochemical methods to show that oxidation of [{Co 2 (CO) 4 (dppm)} 2 (-PhC 2 C 2 Ph)] in which two tetrahedrane clusters are linked by a C-C single bond, gives rise to a mono-cation in which the cluster centres are in identical electronic environments on the IR timescale [47].…”