Nickel(II) chain with alternating end-on/end-to-end single azido bridges:: A combined structural, magnetic, and theoretical study

The reaction of a tridentate Schiff base LH (L-: 1,1,1-trifluoro-7-(dimethylamino)-4-methyl-5-aza-3-hepten-2-onato) with a Ni(II) salt in the presence of azide salt has led to a new alternating end-on (EO)/end-to-end (EE) azidobridged Ni(II) chain of formula {[Ni-2(mu(1,1)-N-3)(mu(1,3)-N-3)(L)(2)(MeOH)(2)]}(n). Its originality lies in the presence of single EE and EO coordination modes for the azide. It crystallizes in the C2/c space group, a = 21.570(7) angstrom, b = 10.79(1) angstrom, c = 16.154(5) angstrom, beta = 120.81(2)degrees, Z = 4. The chain can be viewed as Ni-2(N-3)(L)(2)(MeOH)(2)}(+) dimeric units linked to each other in a zigzag pattern by the other azide. Magnetic susceptibility and magnetization measurements have been performed and revealed that the chain can magnetically be depicted as isolated {Ni-2(N3)1 units exhibiting antiferromagnetic interaction (J(AF) similar to -37 cm(-1)). Ab initio calculations confirmed the efficient magnetic coupling through the EE bridge and vanishingly small EO {Ni-2((mu 1,1)-N-3)} interactions.