Combination of primary amide and dipyrrin for the elaboration of extended architectures built upon both coordination and hydrogen bonding

Abstract

The 5-(benzamide)dipyrrin, a ditopic tecton bearing two different interaction poles, i.e. a primary amide as H-bond donor and acceptor and a deprotonated dipyrrin unit as a strong chelating group leads in the presence of metal cations (Cu(II), Zn(II..)) or metal complexes ([Cu(II)-acac]⁺ and [Co(III)-salen]⁺) to homo- and heteroleptic complexes. The latter behave as metallo-organic tectons and generate in the crystalline phase molecular networks. Whereas the homoleptic Cu complex leads to the formation of a 2-D network, its Zn analogue forms a 1-D ribbon type architecture owing to the presence of capping dioxane molecules. For the heteroleptic complexes, in the case of the Cu-acac, a 1-D network resulting from bridging of H-bonded dimers of dimers by dioxane molecules is observed whereas for the Co-salen, due to the salen ligand offering further hydrogen bonding capabilities, two different solvates with different connectivity patterns have been obtained.