Structural diversity of copper(i)-ethylene complexes with 2,4-bis(2-pyridyl)pyrimidine directed by anions

The 3 : 1 reaction of [Cu(C2H4)(n)]ClO4 with 2,4-bis(2-pyridyl)pyrimidine (bpprd) in Me2CO under C2H4 afforded yellow prism crystals of the dinuclear Cu(I)-C2H4 complex [Cu-2(bpprd)(eta(2)-C2H4)(2)(ClO4)(2)] (1). The 3 : 1 reaction of [Cu(C2H4)(n)]NO3 with bpprd in Me2CO under C2H4 afforded yellow plate crystals of the tetranuclear Cu(I)-C2H4 complex [Cu-4(bpprd)(2)(eta(2)-C2H4)(4)(mu-NO3)(2)](NO3)(2) (2). The 10 : 1 reaction of [Cu(C2H4)(n)]BF4 with bpprd in Me2CO under C2H4 afforded yellow plate crystals of the dinuclear Cu(I)-C2H4 complex [Cu-2(bpprd)(eta(2)-C2H4)(2)(BF4)]BF4 (3). The 3 : 1 reaction of [Cu(C2H4)(n)]BF4 with bpprd in Me2CO under C2H4 afforded red prism crystals of the polymeric Cu(I)-C2H4 complex {[Cu-6(bpprd)(4)(eta(2)-C2H4)(2)(mu-eta(2):eta(2)-C2H4)(mu-BF4)(2)](BF4)(4)}(n) (4). The X-ray crystal structures of complexes 1-4 have been determined. The structural diversity of Cu(I)-C2H4 complexes bridged by bpprd with different anions was demonstrated. The 1D Cu(I)-bpprd/C2H4 coordination polymer 4 bridged by unusual mu-eta(2):eta(2)-C2H4 and the mu-BF4- anion is of particular significance. Complex 1 exhibited relatively well-resolved H-1 NMR signals of bpprd and C2H4 (delta = 4.97 ppm) in (CD3)(2)CO at 23 degrees C.

Automated summary

The crystal structures of Cu(I)-C2H4 complexes with different ligands and reaction conditions have been determined. Among them, the coordination polymer 4 bridged by unusual mu-eta(2):eta(2)-C2H4 and mu-BF4- has particular significance.