Examples of Heterometallic 3d–3d Azido Complexes by One-Pot Synthesis



The assembly of CuII, MII (CoII or NiII), azido, and isonicotinate acid N-oxide under hydrothermal conditions straightforwardly gives two isomorphic heterometallic 3d–3d azido complexes formulated [Cu2M(N3)4(INO)2(H2O)4] (INO = isonicotinate N-oxide; M = Co for 1 and Ni for 2). In the structure of the complexes, CuII ions have a trigonal-bipyramidal-coordinated configuration, whereas the MII ions have octahedral geometry with two water molecules in the apical positions. The structure of the complexes is based on azido-carboxylate mixed-coordination Cu–M–Cu trimers, which are further linked by double end-on (EO) azido anions through the CuII ions to form a chain structure, and the 1D structure can be described as EO azido/syn–syn carboxylates and double EO azido mixed-bridge spin-sequence chains with –1/2–J1–3/2–J1–1/2–J2–1/2– for 1 and –1/2–J1–1–J1–1/2–J21/2– for 2. Magnetic studies indicated that 1 and 2 are both metamagnets for the weak antiferromagnetic interactions between the ferromagnetic chains.