Synthesis and Characterization of Copper(II) and Nikel(II) Complexes of 1,5-Diamino-3-pentanol and Its Derivatives

Dihydrochloride of a binucleating ligand, 1,5-diamino-3-pentanol (Hdpl·2HCl) has been synthesized by a new method in a high yield (>70%). This ligand forms 1 : 1 complexes with copper(II), Cu(dpl)X(X=BF4, ClO4, NO3, and Cl(H2O)). The cryomagnetic study of the copper complexes has shown that they are binuclear, and a strong antiferromagnetic interaction is operating between two copper ions. The binuclear structure seems to be quite stable even in aqueous solution. The 1 : 1 complex with nickel(II) was also isolated as tetraphenylborate, which was essentially diamagnetic. A planar binuclear structure similar to the copper complexes was assumed for this complex. Its absorption band at 29.8×103 cm−1 (ε=160) was attributed to the charge transfer transition from the bridging oxygen to the nickel similarly to the bands in the 25–29×103 cm−1 region usually observed for alkoxo-oxygen bridged binuclear copper(II) complexes. Some 2 : 1 copper(II)–dpl complexes have also been synthesized and characterized as binuclear complexes. 1,5-Bis(dimethylamino)-3-pentanol has been synthesized, and its 2 : 1 copper(II) complexes have been isolated.