Synthesis, structures, and magnetic properties of two pyrazolato-bridged trinuclear copper(II) complexes

One nonlinear and one linear trinuclear copper(II) complex [Cu3(dien)2(pdc)2CH3OH]2 center dot 6CH3OH (1) and [Cu3(pdc)2(CH3OH)6(H2O)4] (2) were prepared and characterized structurally, where dien is diethylenetriamine and pdc3- the trianion of 3,5-pyrazoledicarboxylic acid. Both complexes consist of 3,5-pyrazoledicarboxylato-bridged trinuclear copper(II) centers. In 1, copper(II) ions are five-coordinate in distorted square pyramids with bond angles 164.78 degrees for Cu(1)-Cu(2)-Cu(3) and 164.51 degrees for Cu(4)-Cu(5)-Cu(6). In 2, the three copper(II) ions are six-coordinate with elongated octahedral geometry. The trinuclear units of 1 and 2 interact through hydrogen bonds to form 3-D and 2-D supramolecular networks, respectively. Variable temperature magnetic susceptibility measurements show that 1 and 2 are antiferromagnetically coupled with J values of -11.2 and -13.3 cm-1.