Structurally Diverse Polynuclear Copper(I) Complexes Bridged by Pyrimidine–, Pyrazine–, and Triazine–based Ligands with Several 2–Pyridyl Groups

Abstract

AbstractThe reactions of [Cu(MeCN)4]BF4 or [Cu(C2H4)n]ClO4 complexes with 4,6–bis(2–pyridyl)pyrimidine (bppym) in Me2CO under C2H4 afforded dinuclear Cu(I)–bppym/C2H4 adducts [Cu2‐(bppym)(C2H4)2](BF4)2•Me2CO (1) and [Cu2(bppym)2(C2H4)2](ClO4)2•Me2CO (2), respectively. One Cu(I) atom is coordinated by bppym and C2H4 in a distorted trigonal–planar geometry. The other Cu(I) atom is coordinated by bppym, Me2CO, and C2H4 toward a distorted tetrahedral geometry. The reaction of [Cu(MeCN)4]BF4 with 2,3–bis(2–pyridyl)pyrazine (bppz) in MeOH under C2H4 afforded a Cu(I)–bppz coordination polymer {[Cu2(bppz)2](BF4)2•MeOH}n (3). Two Cu(I) atoms are alternately bridged by two bppz to form a 1–D zigzag–chain structure. Each Cu(I) coordination sphere is largely distorted from a normal tetrahedral structure toward a square planar structure. The reaction of [Cu(MeCN)4]PF6 with 2,4,6–tris(2–pyridyl)–s–triazine (tptz) in MeEtCO under C2H4 afforded a tetranuclear Cu(I)–tptz/C2H4 adduct [Cu4(tptz)2(C2H4)2(MeCN)2](PF6)4•MeEtCO (4 b). Two Cu(I) atoms are bridged by the central triazine ring, the 2–pyridyl group, the central triazine ring, and the 2–pyridyl group in a different tptz to form a double helical structure. The other Cu(I) atom is coordinated by the central triazine ring, the 2–pyridyl group, MeCN, and C2H4 in a distorted tetrahedral geometry. The reaction of [Cu(MeCN)4]PF6 with tetra–2–pyridylpyrazine (tppz) in MeOH under C2H4 afforded a tetranuclear Cu(I)–tppz complex [Cu4(tppz)2(MeCN)4](PF6)4•MeOH (5 a). Each Cu(I) atom is coordinated by the central pyrazine ring, the 2–pyridyl group, the 2–pyridyl group in a different tppz, and MeCN in a distorted tetrahedral geometry. These four Cu(I) atoms are bridged by the two opposite tppz ligands to form a unique tetranuclear Cu(I) cage structure.