26816-79-5Relevant academic research and scientific papers
Hybrid α-Diimine/Bis(chalcogenoether) Ligands for Copper(I) and Copper(II) Complexes
Bubrin, Martina,Kvapilová, Hana,Fiedler, Jan,Ehret, Fabian,Záli?, Stanislav,Kaim, Wolfgang
, p. 661 - 670 (2018)
The new ligands L = 1,4-bis(2-methylchalcogenophenyl)-2,3-dimethyl-1,4-diaza-1,3-diene [chalcogen = O (1), S (2) or Se (3)] have been studied in their coordination behavior towards CuI and CuII. Whereas the O-ether containing ligand forms complex ions [Cu(L)2]n+ = 4n+, with exclusive N-coordination (n = 1) or N and weaker O coordination (n = 2), the species with E = S or Se contain tetradentate ligands in [Cu(L)]+ (5+, 6+) and [Cu(L)L′]n+ [n = 1, L′ = TfO– (E = S) or n = 2 and L′ = H2O (E = Se)]. Molecular structures in the crystals of 5+ and 6+ show distorted tetrahedral N coordination at the metal and innocently behaving α-diimine functions, in agreement with spectroscopic and computational data. The copper(II) ions [Cu(L)L′]2+ with one tetradentate ligand L = 2 or 3 exhibit a square-pyramidal configuration at the metal. Two isolated crystalline forms of 42+ show weak coordination (2.636–2.96 ?) of three or four ether oxygen atoms, resulting in 4+3 or 4+4 coordination arrangements for N and O donors, respectively. In agreement with the rather different CuI and CuII structures the electrochemical oxidation of the copper(I) complexes and the reduction of the corresponding CuII species reveal an ECEC behavior within a square scheme, whereas the reduction of the CuI compounds, most likely at the diimine site, proceeds irreversibly. UV/Vis spectroelectrochemical results showing intense MLCT and IL absorptions were analyzed with the help of TD-DFT calculations.
