CRYSTAL-STRUCTURE OF A SILVER(I) COMPLEX WITH THE 1,2,4,5-BENZENETETRACARBOXYLIC ACID (PYROMELLITIC ACID)

The reaction between freshly precipitated silver oxide Ag2O and an aqu eous solution of tetrabenzenecarboxylic acid H4L leads to the anhydrou s Ag2H2L complex. It crystallizes in the space group P2(1)/c, with a = 6.457(1), b = 8.180(1), c = 9.982(1) Angstrom, beta = 97.83(1)degrees , V = 522.3(1) Angstrom(3), Z = 2, d = 2.976 g cm(-3). This structure is a three dimensional polymeric network polymer without any silver si lver interaction. The silver environment is a bipyramid trigonal polyh edron with three short bond distances in the equatorial plane (Ag-O = 2.255(2), 2.295(2), and 2.499(2) Angstrom) and two longer bond distanc es in axial positions (Ag-O = 2.558(2) and 2.617(2) Angstrom). Thus, t he silver polyhedron involves five different ligands. It is noteworthy that the (H2L2)(2-) ligand is located around an inversion centre.