mu-BENZENE-1,2,4,5-TETRACARBOXYLATO-kappa O-2(1)O-4)BIS-[AQUA-BIS-2-(AMINOMETHYL) PYRIDINE-kappa N-2,N ') NICKEL (II)] DECAHYDRATE: STRUCTURE AND MAGNETIC PROPERTIES
Abstract
mu-Benzene-1,2,4,5-tetracarboxylato-kappa O-2(1)O-4)bis-[aqua-bis-2-(aminomethyl) pyridine-kappa N-2,N') nickel (II)] decahydrate, [Ni-2(amp)(4)(btc)(H2O)(2)]center dot 10H(2)O has been synthesized and its crystal structure determined by X-ray diffraction. The complex crystallizes in the Monoclinic space group P2(1)/n with cell dimensions a= 11.0102 (10) angstrom, b = 21.5416 (19) angstrom, c = 11.0445 (10) angstrom and beta = 118.753 (1)degrees, and two formula units per cell (Z = 2, Z' = 0.5). The structure consists of centrosymmetric dimeric units in which the benzene tetracarboxylate anions (btc) bridge the symmetry-related nickel (II) cations, two bidentate chelating molecules of 2-(aminomethyl) pyridine and a terminal aqua ligand completing the six-fold coordination at each metal. These dimers link to each other via H-bonding to form chains parallel to [100], while the water solvates form a strongly bound 2D network parallel to (100), made up by small (R-4(4)(8)) and large (R-20(20)(40)) rings, the latter ones "pierced" by the chains of dimmers, with a profuse H-bonding interconnection between both substructures. Magnetic susceptibility measurements as a function of temperature disclose weak interdimeric exchange interactions. Fitting of these data to a dimeric model yields J=-3.5 cm(-1) and g=2.13.
Domains
Chemical Sciences
Origin : Publisher files allowed on an open archive
Loading...