Structures and Solid-State Dynamics of One-Dimensional Water Chains Stabilized by Imidazole Channels


  • We gratefully acknowledge the support of the University of Louisville and the National Science Fundation (Grant No. CHE-0328406) (R.M.B. and RJW), the Kentucky Science and Engineering Foundation (Grant No. KSEF-275-RDE-003) (R.M.B.), the National Institutes of Health (Grant No. AR41751-07) (R.J.W.), and the Kentucky Research Challenge Trust Fund for the upgrade of our X-ray facilities. Special thanks to Dr. George R. Pack and Dr. Craig A. Grapperhaus for helpful discussions, and Dr. Usha M. Gundusharma (Kimberly-Clark) and Rodica McCoy for their assistance with the TGA and DSC measurements.


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Proton wires: One-dimensional water chains play an important role in proton permeation through transmembrane proteins. The X-ray crystal structures as well as solid-state 2H and 17O NMR and calorimetry studies of two imidazole hydrates that stabilize infinite one-dimensional water chains are reported (see picture; N blue, O red, H white). The 2H NMR spectroscopic studies suggest that water molecules in both compounds undergo different reorientational dynamics.