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

The 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 [Cu-2-(bppym)(C2H4)2](BF4)(2)center dot Me2CO (1) and [Cu-2(bppym)(2)(C2H4)(2)](ClO4)(2)center dot 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 {[Cu-2(bppz)(2)](BF4)(2)center dot 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 [Cu-4(tptz)(2)(C2H4)(2)(MeCN)(2)](PF6)(4)center dot MeEtCO (4b). 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 [Cu-4(tppz)(2)(MeCN)(4)](PF6)(4)center dot MeOH (5a). 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.