TRINUCLEAR COPPER(II) COORDINATION-COMPOUNDS WITH THE NEW LIGAND S-(3-AMINO-4H-1,2,4-TRIAZOL-5-YL)-3,7-DITHIANONANE - X-RAY STRUCTURES AND MAGNETOCHEMISTRY

The syntheses of three new trinuclear copper(II) complexes with the li gand 1,9-bis-(3-amino-4H-triazol-5-yl)-3,7-dithianonane (attn) are des cribed. The X-ray structures of two of them, [Cu-3(attn)(2)(H2O)(2)Cl- 2]Cl-4(H2O)(4) (1) and [Cu-3(attn)(2)(ZnCl4)(2)Cl-2](H2O)(4) (2), have been solved. The magnetic properties of these and those of the third related complex, [Cu-3(attn)(2)(H2O)(2)Br-2]Br-4(H2O)(4) (3), have bee n studied. Crystallographic data: 1: Cu3Cl6C22H52N16O6S4, P (1) over b ar, a = 8.003(3), b = 11.330(4), c = 13.072(6) Angstrom, alpha = 112.3 6(3), beta = 90.62(3), gamma = 96.64(3)degrees, Z = 1, V = 1087(1) Ang strom(3), least-squares refinement based on 8956 significant reflectio ns converged to R (R(w)) = 0.028(0.037); 2: Cu3Zn2Cl10C22H48N16O4S4, P 2(1)/c, a = 8.248(5), b = 28.203(3), c = 10.405(4) Angstrom, beta = 93 .07(2)degrees, Z = 2, V = 2417(2) Angstrom(3), refinement based on 151 0 significant reflections converged to R (R(w)) = 0.043(0.049); 3 is i somorphous to 1. The structures consist of linear trinuclear units of three copper(II) ions bridged by two triazole N1N2 bridges and one chl oride. The central copper ion lies on a centre of symmetry, coordinate d by 4 N and 2 Cl. The coordination distances in Angstrom are: 1: Cu-N = 2.040(1) and 1.985(1), Cu-Cl(bridging) = 2.7390(3); 2: Cu-N = 2.04( 1) and 1.98(1), and Cu-Cl(bridging) = 2.878(3). The terminal copper io ns are coordinated by N2S2Cl1O1 (1) and N2S2Cl2 (2), respectively. The distances in Angstrom are for 1: Cu-N = 2.003(1) and 2.023(1), Cu-S = 2.3854(3) and 2.3637(3), Cu-Cl(bridging) = 2.5505(3), Cu-O(water) = 2 .659(1); for 2: Cu-N = 1.99(1) and 1.98(1), Cu-S = 2.369(4) and 2.390( 4), Cu-Cl(bridging) = 2.713(4), Cu-Cl-ZnCl3 = 2.979(5). The shortest C u-Cu distances within one cluster are 3.5426(1) and 3.620(3) A for 1 a nd 2, respectively. The magnetic susceptibility data have been interpr eted on the basis of Heisenberg intracluster interactions (J = -75.1, -70.9, -72.3 cm(-1) for compounds 1, 2, 3, respectively); a small inte rcluster exchange (zj' = +1.47, +0.81, +2.03 cm(-1) for 1, 2 and 3, re spectively) has been taken into account in the mean field approximatio n.