Shedding Light on the Protonation States and Location of Protonated N Atoms of Adenine in Metal-Organic Frameworks

Gladysiak, Andrzej, Nguyen, Tu N, Anderson, Samantha L, Boyd, Peter G, Palgrave, Robert G, Bacsa, John, Smit, Berend, Rosseinsky, Matthew J ORCID: 0000-0002-1910-2483 and Stylianou, Kyriakos C (2018) Shedding Light on the Protonation States and Location of Protonated N Atoms of Adenine in Metal-Organic Frameworks INORGANIC CHEMISTRY, 57 (4). pp. 1888-1900. ISSN 0020-1669, 1520-510X

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Abstract

We report the syntheses and structures of five metal-organic frameworks (MOFs) based on transition metals (Ni^II, Cu^II, and Zn^II), adenine, and di-, tri-, and tetra-carboxylate ligands. Adenine, with multiple N donor sites, was found to coordinate to the metal centers in different binding modes including bidentate (through N7 and N9, or N3 and N9) and tridentate (through N3, N7, and N9). Systematic investigations of the protonation states of adenine in each MOF structure via X-ray photoelectron spectroscopy revealed that adenine can be selectively protonated through N1, N3, or N7. The positions of H atoms connected to the N atoms were found from the electron density maps, and further supported by the study of C-N-C bond angles compared to the literature reports. DFT calculations were performed to geometrically optimize and energetically assess the structures simulated with different protonation modes. The present study highlights the rich coordination chemistry of adenine and provides a method for the determination of its protonation states and the location of protonated N atoms of adenine within MOFs, a task that would be challenging in complicated adenine-based MOF structures.

Item Type:	Article
Uncontrolled Keywords:	3402 Inorganic Chemistry, 34 Chemical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	09 Mar 2018 15:43
Last Modified:	16 Jun 2026 05:17
DOI:	10.1021/acs.inorgchem.7b02761
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3018811
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