On basis of the broken symmetry approach and density functional theory (DFT), the magnetostructural characterization of azido-bridged c Cu(Ⅱ) dimers is studied which have end - to - end (EE) and end - on (EO) two main coordination modes. The calculating results show that EE mode gives antiferromagnetic interaction, whereas EO mode gives ferromagnetic coupling in which θis about 91°～107 °, basically agreealde with the experimental value 96°～104 °. The essence of the magnetostructural characterization lies in d - p - d three centers σ antibonding action between two Cu dxy orbitals and bridged N px orbital in SOMO b1g. In the θ region of 95°～ 110 ° the σ antibonding overlap has the maximum, which leads to the maximum ferromagnetic coupling. It is also shown that τhas no great influence on J, whereas J decreases linearly with increasing rCu-Nμ.

Key words: BRIDGE BOND, SYMMETRY, FAILURE, DINUCLEAR COMPLEX, AZIDO COMPLEX, FERROMAGNETIC MATERIALS, COPPER COMPLEX, STRUCTURE ACTIVITY RELATIONSHIP