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Hybrid α‐Diimine/Bis(chalcogenoether) Ligands for Copper(I) and Copper(II) Complexes
Author(s) -
Bubrin Martina,
Kvapilová Hana,
Fiedler Jan,
Ehret Fabian,
Záliš Stanislav,
Kaim Wolfgang
Publication year - 2018
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201800073
Subject(s) - diimine , copper , chemistry , ligand (biochemistry) , square pyramidal molecular geometry , crystallography , metal , coordination number , electrochemistry , coordination geometry , chalcogen , crystal structure , ether , ion , coordination complex , stereochemistry , molecule , hydrogen bond , organic chemistry , biochemistry , receptor , electrode , catalysis
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 Cu I and Cu II . Whereas the O‐ether containing ligand forms complex ions [Cu(L) 2 ] n + = 4 n + , 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′ = H 2 O ( 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 4 2+ show weak coordination (2.636–2.96 Å) 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 Cu I and Cu II structures the electrochemical oxidation of the copper(I) complexes and the reduction of the corresponding Cu II species reveal an ECEC behavior within a square scheme, whereas the reduction of the Cu I 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.