Mixtures obtained by reacting trans-(+/-)-1,2-diaminocyclohexane with acetylacetone in the presence of simple cobalt(II) salts

In the absence of a metal ion, racemic trans-1,2-diaminocyclohexane (trans- (+/- )DCH) reacts with acetylacetone (acacH) (1:2.5 mole ratio) to form the bisoxoenamine condensation product, boe (1). CoCl2-6H(2)O and CO(ClO4)(2). 6H(2)O each react with trans-(+/- )DCH in air to give complexes containing the oxidised Co(III) ion, [Co((+/- )DCH)(3)](3+), which does not subsequent ly react with added acacH to give a Schiff base complex. Mixtures of comple xes are obtained from one-pot reactions involving trans-(+/- )DCH, a simple Co(II) salt and acacH (1:1:2.5 mole ratio). When CoCl2.6H(2)O is used, the mixed-ligand Co(II) complex [Co((+/- )DCH)Cl-2] (4) precipitates first and , after a period of weeks, the Co(II) complex (diazH)(2)[CoCl4] (5) (diazH( +) is a diazepinium cation), the Co(II) complex [Co(boe)Cl-2](n) (6) and th e Co(III) complex [Co(acac)(3)] (7). co-crystallise from the mother liquor. Using Co(ClO4)(2).6H(2)O in the reaction with trans-(+/- )DCH and acacH al so gives a mixture of products. Complexes 7, the Co(II) complex [Co-2(acac) (4)(H2O)(2)][Co(acac)(H2O)(4)]ClO4.EtOH (8) and the Co(III) complex [Co(aca c)(2)(+/- )DCH]ClO4 (9) co-crystallise. Complexes 1, 5, 7, 8 and 9 were cha racterised using X-ray crystallography. The major difference between using CoCl2.6H(2)O and CO(ClO4)(2).6H(2)O in reactions involving (+/- )DCH and ac acH is that no DCH/acacH condensation products are identified in the produc t mixtures when the perchlorate salt is employed. (C) 2001 Elsevier Science Ltd. All rights reserved.