Ferromagnetic interaction in mu(1,3)-cyanamido-derived copper(II) cryptates

摘要

The reaction of dinuclear copper(II) cryptates with calcium cyanamide, CaNCN, and sodium dicyanamide, Na[N(CN)(2)] results in dinuclear compounds of formulae [Cu-2(HNCN)(R3Bm)](ClO4)(3) (1), [Cu-2(dca)(R3Bm)](ClO4)(3).4H(2)O (2), and [Cu-2(NCNCONH2)(R3Bm)](CF3SO3), (3), in which R3Bm=N[(CH2)(2)NHCH2(C6H4-m)CH2NH(CH2)(2)](3)N and dca=dicyanamido ligand (NCNCN-). The X-ray diffraction analysis reveals for both 1 and 3 a dinuclear entity in which the copper atoms are bridged by means of the -NCN- unit. The molar magnetic susceptibility measurements of 1-3 in the 2-300K range indicate ferromagnetic coupling. The calculated J values, by using theoretical methods based on density functional theory (DFT) are in excellent agreement with the experimental data. Catalytic hydration of a nitrile to an amide functional group is assumed responsible for the formation of 3 from a mu(1,3)-dicyanamido ligand.