Hydrogen-bonded chains of α,ω-diaminoalkane and α,ω-dihydroxyalkane guest molecules lead to disrupted tunnel structures in urea inclusion compounds?

New Journal of Chemistry Pub Date: 2005-08-09 DOI: 10.1039/B502004M

Abstract

Structural features of the urea inclusion compounds containing 1 ∶ 1 mixtures of α,ω-diaminoalkane and α,ω-dihydroxyalkane guest molecules, reported in this paper, provide interesting contrasts to those of conventional urea inclusion compounds. All the α,ω-diaminoalkane/α,ω-dihydroxyalkane/urea inclusion compounds reported have a hydrogen-bonded chain of alternating α,ω-diaminoalkane and α,ω-dihydroxyalkane guest molecules, which is surrounded by urea molecules in a manner that bears some resemblance to the conventional urea tunnel structure, but with the urea–urea hydrogen bonding scheme disrupted by the formation of N–H?O hydrogen bonds between NH2 groups of the urea molecules and OH groups of the α,ω-dihydroxyalkane molecules. As a consequence, the guest and host components have the same periodicity, and these inclusion compounds are commensurate, in contrast to conventional urea inclusion compounds. So far, attempts to prepare α,ω-diaminoalkane/α,ω-dihydroxyalkane/urea inclusion compounds for α,ω-dihydroxyalkanes longer than 1,3-dihydroxypropane have been unsuccessful, suggesting that there may be an upper limit to the length of the α,ω-dihydroxyalkane component in this family of structures.

Graphical abstract: Hydrogen-bonded chains of α,ω-diaminoalkane and α,ω-dihydroxyalkane guest molecules lead to disrupted tunnel structures in urea inclusion compounds
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