Nickel(II) complexes with nitrogen-containing derivatives of the closo-decaborate anion

The reactions of the salt (Bu4N)[2-B10H9O2C4H8] (1) with ammonia and ethylenediamine in ethanol were studied. These reactions afford substituted closo-decaborates with nitrogencontaining groups linked to the cluster through a diethylene glycol spacer. Using this method, we synthesized derivatives of the closo-decaborate anion with the pendant groups -NH3 (+) and -NHCH2CH2NH2; the complexes [Ni(H2O)(en)(L)] (7) and [Ni(en)(L)]center dot 0.5H(2)O (8), where L = [2-B10H9O(CH2)(2)O(CH2)(2)NH(CH2)(2)NH2](2-), were synthesized. The X-ray diffraction study showed that the coordination sphere of the Ni2+ ions in complexes 7 and 8 have the same composition (4 N + 2 O). However, the coordination environment differs in the nature of the oxygen atom. Thus the oxygen atom directly bonded to the boron cluster is involved in the coordination of the metal ion in compound 8, whereas a water molecule is involved in the coordination in compound 7.