Trinuclear copper(II) complexes with bridging (N-N) diazine ligands: structural and magnetic studies

The polytopic ligands 2poap and po2p have a linear disposition of coordinat ion pockets suitably disposed to bind metal ions in close proximity and pro duce linear trinuclear copper(II) complexes. The complexes [Cu-3(2poap - 2H )(CH3CO2)(4)]. 3H(2)O (1), [Cu-3(2poap - 2H)(H2O)(DMF)(3)(CH3OH)(2)](BF4)(4 ) (2), and [Cu-3(po2p - H)(2)(H2O)(2)](ClO4)(4). 2H(2)O (3) have a linear a rrangement of Cu(II) centres linked by a trans arrangement of N-N single bo nds. Each metal is assigned a d(x2-y2) magnetic ground state, and the trans diazine bridging arrangement leads to strong antiferromagnetic coupling in complete agreement with previous magnetostructural correlations relating t he twist of the copper magnetic planes around the N-N bond to the exchange integral.