A novel one-dimensional chain compound [Cu(dafo)_2 (H_2O)_2] (OPA) _2 was synthesized. Its structure was determined by single-crystal X- ray diffraction. The crystal belongs to monoclinic system, P2 (1)/n space group. The crystallographic data are: a = 0.71093 (16) nm, b = 1. 5724(4) nm, c = 1.5357(3) nm, α=90.000(5) °, β= 102.220(4) °, γ=90. 000(5) °, V = 1.6778 (6)nm~3, Z = 2, F(000) = 814, M_r = 794.17, D_c = 1.527 g/cm3, μ= 0.727 mm~(-1), R_1 = 0.0406, wR_2 = 0.0930. The analysis of the crystal structure indicates that the compound has a one-dimensional chain structure, which is formed by hydrogen bonds.

Key words: COPPER COMPLEX, CRYSTAL STRUCTURE, SUPERMOLECULAR STRUCTURE, FLUORENONE P, O-BENZENEDICARBOXYLIC ACID, COPPER NITRATE