A Novel Azido and Pyrazine-Dioxide Bridged Three-Dimensional Manganese(II) Network with Antiferromagnetic Ordering (TN ) 62 K) and a Spin Flop State

Bao-Qing Ma,† Hao-Ling Sun,† Song Gao,*,† and Gang Su‡

State Key Laboratory of Rare Earth Materials Chemistry and Applications & PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, People’s Republic of China, and Department of Physics, Graduate School at Beijing, University of Science and Technology of China, CAS, P.O. Box 3908, Beijing 100039, China

Received November 28, 2000 Revised Manuscript Received March 1, 2001

Much attention has been paid to the molecule-based magnetic materials in the past decades.1 The azide ligand is a suitable candidate for the design of magnetic coordination polymers because of its good superexchange pathway.2 Its end-to-end (EE) and end-on (EO) coordination modes favor antiferromagnetic and ferromagnetic interactions, respectively. Furthermore, the magnetic properties can be tuned by modifying the bond parameters of the bridging region. The high-dimensional networks are of particular interest, as it is believed that the bulk magnetic properties can be enhanced by increasing the dimensionality. One of the synthetic strategies to high-dimensional azides is to increase the number of azide ligands by adding a countercation, such as in Csn[Mn(N3)3]n, 3 [N(C2H5)4]n[Mn2(N3)5(H2O)]n, 3 Cs2n[Co3(N3)8]n, 4 Cs2[Ni(N3)4]‚H2O,4 and [N(CH3)4][Mn(N3)3].5 Another is the introduction of a second bridging ligand to extend the architectures such as in [Mn2(N3)4- (bipym)]n 6 and [MnL(N3)2]n (L ) 4,4′-bipy,7 pyrazine,8 1,2-bis(4-pyridyl)ethane9). Using the latter approach, we succeeded in assembling a three-dimensional (3D) network, Mn(N3)2(pzdo) (1), through azide and pyrazinedioxide (pzdo) ligands. Its structure and magnetic properties are presented herein