Co(trz)

ne sont entour6s que de 12 voisins (environnement icosa+drique: 7,6-10,3 A). Toutes ces remarques viennent ainsi justifier le comportement particulier d6jfi signal6 pour Cr(1), quant fi son orientation et son mode de cohesion intermol6culaire.Cette description met donc en +vidence que (+)-[Cr(en)3]Br3.0,6H20 poss+de un arrangement structural de seN ions complexes, de type pseudocubique, correspondant fi une maille cristalline construite sur les trois axes orthorhombiques [1001, 10111 et [01i1 (param&res: 21,02, 22,5 et 22,5 A reflexions) and 0.034 (R w --0.041, 1217 reflexions) for the Co, Zn and Cu compounds respectively. All three compounds exhibit the same basic features, namely two-dimensional M H networks with 2,4-bridging triazole molecules and NCS-groups, acting as N donors, on either side of the planes. The MIIN6 octahedra are tilted. Hydrogen bonding is shown to be present between neighbouring layers. For the Co complex, a satisfactory result could only be obtained by imposing constraints upon the triazole ring and by introducing an inversion centre, implying 50% disorder in the orientation of the triazole rings.

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