I. Efimenko, A. Churakov, O. S. Erofeeva
Sep 1, 2019
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Journal
Russian Journal of Coordination Chemistry
Abstract
The effect of the nature of halogen-substituted carboxylic acids RCOOH, where R is ClCH2, Cl2CH, Cl3C, or F3C, on the complexation of palladium halocarboxylates with morpholine C4H9NO was investigated. Reactions with ClCH2COOH and Cl2CHCOOH gave binuclear complexes [(C4H9NO)2Pd2(μ-OOCR)2(OOCR)2] with palladium-coordinated morpholine, whereas reactions with Cl3CCOOH and F3CCOOH afforded the first tetra(halocarboxylate) palladium complexes with protonated morpholine as the cation, (C4H10NO)2[Pd(RCOO)4]. The acid–base balance of morpholine and halocarboxylic acid was the key factor determining the composition of the resulting complexes. For the formation of palladium tetra(halocarboxylates) with morpholine, the difference between the morpholine and acid pKa values should be not lower than 7.63. X-ray diffraction studies were carried out for the first tetra(halocarboxylate) palladium complex with a monocarboxylic acid (C4H10NO)2[Pd(OOCCF3)4 ∙ 2H2O] (I) and for trans-[(C4H9NO)2Pd(OOCCH2Cl)2 ∙ 2H2O] (II), trans-[(C4H9NO)2Pd(OOCCHCl2)2] (III), and trans-[(C4H9NO)2Pd(OOCCF3)2 ∙ 2H2O] (IV) (CIF files CCDC nos. 1008564, 1894300, 1008566, and 1894299, respectively).