Synthesis, structure, and theoretical study of the nonclassical [CuTe(7)](3-) anion

The compound PPh(4)](2)NEt(4)]CuTe(7)] has been synthesized from the reaction of CuCl with a polytelluride solution in dimethylformamide at room temperature. The compound crystallizes with two formula units in the triclinic space group P(-)1 in a cell with dimensions a = 8.9507(18) A, b = 14.714(3) A, and c = 23.277(5) A and alpha= 86.32(3) degrees, beta= 80.17(3) degrees, and gamma= 75.63(3) degrees (T = -120 degrees C). Ab initio calculations indicate that the nonclassical CuTe(7)](3)(-) anion is the result of joining Te(3)(2-) and CuTe(4)](1-) fragments through donor-acceptor interactions.