Self-assembly of 3d-4f "square-in-square" coordination clusters based on substituted diethanolamine ligands

The combination of substituted N-diethanolamine and pivalic (or benzoic) acid ligands has proved to be an extremely fruitful route for assembling in solution 3d/4f blends of metal ions within coordination clusters. In this article we wish to focus on the analysis of the synthetic routes for accessing 3d-Dy(III) coordination clusters with an overall [(MDy4III)-Dy-III(mu(3)-X)(4)(O2CBut)(4)(O2CBut)(8)(x-dea)(4)].solv formulation, where M = Mn, x = tert-butyl, X = N-3 (1), X = OCN (2), X= NO3 (3); M = Cr, x = methyl, X= N-3 (4); solv = MeCN or toluene, and [(FeDY4III)-D-III(mu 3-OH)(4)(O2CC6H4CFH3)(12)(n-bdea)(4)].2CH(3)CN (5). The metal topology in the aggregates can be described as consisting of a "Dy-4-square inscribed in a M-4-square". Complexes 1-4 were prepared from reaction of t-butyldiethanolamine (t-bdeaH(2)) or methyldiethanolamine (mdeaH2) with preformed polynuclear compounds or simple salts of transition metals (Mn(II) and Cr(II)), Dy(NO3)(3).6H(2)O and in the presence or absence of NaN3 or NaNCO if appropriate. Complex 5 was obtained from the reaction between n-bdeaH(2) and Dy(NO3)3.6H(2)O with [Fe3O(m-CH3C6H4COO)(6)(H2O)(C2H2OH)(2)](NO3).2H(2)O. It was found that the nature of the central bridging ligands, i.e. N-3, OCN or NO3, does not appear to have significant influence on the structural features of the isolated manganese derivatives. Concerning the synthesis of the Fe derivative, it was found important to use a different type of diethanolamine ligand and a different carboxylic acid as well. (C) 2016 Elsevier B.V. All rights reserved.