SYNTHESIS AND STRUCTURES OF INFINITE SHEET COPPER(I) COMPLEX POLYMERS WITH 2,6-DIMETHYLPYRAZINE, ([CU2(C6H8N2)3](CLO4)2(C3H6O)2)INFINITY, AND WITH 2-CHLOROPYRAZINE, ([CU2(C4H3N2CL)4.5](CLO4)2)INFINITY

The new copper(I) coordination polymers, {[Cu2(2,6-Me2pz)3](ClO4)2(C3H6O)2}infinity (1) and {[Cu2(2-Clpz)4.5](ClO4)2}infinity (2) (2,6-Me2pz = 2,6-dimethylpyrazine; 2-Clpz = 2-chloropyrazine) have been synthesized and their structures have been X-ray crystallographically characterized. 1 crystallizes in the monoclinic, space group P2(1)/a with a = 15.520(5), b = 19.315(2), c = 12.493(2) angstrom, beta = 110.82(2)-degrees, U = 3322(2) angstrom3, and Z = 4. 2 is orthorhombic, space group Pbca with a = 28.567(6), b = 17.560(9), c = 11.512(9) angstrom, U = 5774(8) angstrom3, and Z = 8. These complexes show an infinite sheet structure of macrocations with uninteracting ClO4- anion. 1 shows planar sheets composed of Cu6, hexagons, in which copper atoms are three-coordinate and linked by 2,6-Me2pz molecules. Acetone molecules sit over the cavities of the Cu6, hexagons, resulting in an intercalated layer between the copper sheets. 2 provides the unique polymers having an unprecedented four coordination geometry in binary copper-pyrazine systems. There are terminal and bridging types of 2-Clpz molecules, which produce Cu6 and Cu4 motifs for infinite pleated sheets. The factors governing the mode of polymerization are found by examination of the crystal structures for a series of copper(I) polymers of pyrazine derivatives.