Study on the Crystal Structure Magnetic Exchange Interaction of (μ-Pyrazine)-BisIminodiacetato Copper(II) Complex

A bridged binuclear complex μ-PyzCu(IDA)₂ had been synthesized, and its single crystal structure had determined in this paper The crystal belong to monoclinic system, and P2₁/c space group. Unit cell Parameters are:a=11.725(3)Å; b=6.630(2)Å; c=14.089(5)Å; β=107.9 (2) and Z=2. Final unweighted factor R=0.080.
The N(1), O(1), O(3) atoms of iminodiacetic arid as tridentiform meridionally coordinate with Cu(Ⅱ) ion and form the equatorial coordination plane with N(2) atom of Pyrazine. Two H₂O molecules coordinate to Cu(Ⅱ) ion in axial direction, and formed a drawing distortional octahedral ligand field. The two Cu(IDA) complexes is bridged by pyrazine. The bihedral angle between the plane of pyrazine ring and the equatorial coordination plane is 47 degree.
ESR measurement shows a weak magnetic exchange interaction between two Cu(Ⅱ) ions through pyrazine bridge.
EHMO calculation shows that q_g and b_1g orbitals of pyrazine are mian contributions to transportation of magnetic exchange interaction. The a_g orbital tyansporte the magnetic exchange interaction passing through σ-exchange mechanism, and the b_1g orbital passing through π-exchange mechanism.
Owing to pyrazine coordination with Cu(Ⅱ) ion is not too strong, so that the pyrazine bridge transporting magnetic exchange interaction also is weak in this complex.