0000000000919009
AUTHOR
Markus Leboschka
Silver(I), Copper(I) and Copper(II) Complex of the New N,Se-Chelate Ligand 2-Phenylselenomethyl-1H-benzimidazole: Electrochemistry and Structure
Abstract. 2-Phenylselenomethyl-1H-benzimidazole (psbi) can form complexes in 2:1 ratio with coinage metal ions. Crystal structure analysis revealed a flattened metal coordination for [AgI(psbi)2](BF4) (1), approaching a distorted planar arrangement with weak Ag-Se bonds (d > 2.9 A) and confirmed as energy minimum by DFT calculations. The typical Jahn-Teller system [CuII(psbi)2Cl2] (2) exhibits a planar CuN2Cl2 core with weak Se---Cu---Se axial ligation (3.2944(8) A Cu--Se distance). The oxygen-sensitive compound [CuI(psbi)2](BF4) (3) exhibits electrochemically reversible oxidation in contrast to the silver(I) analogue 1.
2-Organoselenomethyl-1H-benzimidazole Complexes of Copper(II) and Copper(I)
Structurally characterized 2-methylselenomethyl-1H-benzimidazole (msbi) is shown to form complexes in 2:1 ratio with copper(II). Whereas the central cation [Cu(msbi)2Cl]+ = 1+ in [Cu(msbi)2Cl]Cl·2MeOH crystallizes in an approximately mixed square-pyramidal/trigonal-bipyramidal structure (τ = 0.52) with the second and third row atoms chlorine and selenium in the equatorial plane, the related [Cu(msbi)2(MeOH)](BF4)2 = [2](BF4)2 exhibits a closer to square-pyramidal arrangement with τ = 0.36 for that complex dication 22+. In both cases, the Cu–N bonds are short at about 1.94 A, whereas the Cu–Se distances vary between 2.62 A for 1+ and ca. 2.54 A for 22+. Slight differences between the Jahn–Te…