Co-crystallisation of cytosine with 1,10-phenanthroline: computational screening and experimental realisation

Hoxha, Kreshnik; Case, David H.; Day, Graeme M.; Prior, Timothy J.

Abstract

Attempts to co-crystallise the nucleobases adenine, thymine, guanine, and cytosine with 1,10-phenanthroline by ball milling and solvent evaporation methods are described. A 1:1 co-crystal of cytosine and 1,10-phenanthroline can be obtained by grinding or by solvent evaporation. The structure contains two crystallographically independent cytosine and two independent 1,10-phenanthroline molecules (Z′ = 2). The cytosine molecules form two similar but crystallographically independent hydrogen-bonded chains, while the 1,10-phenanthroline molecules are arranged in π-stacks. Between the chains of cytosine and the π-stacks exist N-H⋯N and C-H⋯N interactions. Crystal structure prediction (CSP) calculations were applied to all four systems to assess their potential for co-crystallisation as well as the likely structures and intermolecular interactions that could result from co-crystallisation. Calculations on the cytosine system demonstrate that co-crystallisation results in a lower energy than the crystalline forms of the two starting materials, in line with the co-crystal formation observed. For the systems which did not form a co-crystal, CSP was used to explore potential packing arrangements, but found none which were lower in energy than that of the pure crystalline forms. In these cases there is significant disruption to the nucleobase hydrogen bonding between the pure compound and the hypothetical co-crystal. For pure adenine and guanine, the hydrogen-bonded ribbons form sheets which must be broken, whereas for thymine, the lack of hydrogen bond donors does not allow the hydrogen bonding present for pure thymine to be maintained while forming thymine-1,10-phenanthroline hydrogen bonds.

Citation

Hoxha, K., Case, D. H., Day, G. M., & Prior, T. J. (2015). Co-crystallisation of cytosine with 1,10-phenanthroline: computational screening and experimental realisation. CrystEngComm RSC, 17(37), 7130-7141. https://doi.org/10.1039/c5ce01286d

• Journal Article Type: Article
• Acceptance Date: Aug 12, 2015
• Publication Date: Aug 12, 2015
• Deposit Date: Sep 10, 2015
• Publicly Available Date: Nov 23, 2017
• Journal: CrystEngComm
• Print ISSN: 1466-8033
• Electronic ISSN: 1466-8033
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 17
• Issue: 37
• Pages: 7130-7141
• DOI: https://doi.org/10.1039/c5ce01286d
• Keywords: General Materials Science; General Chemistry; Condensed Matter Physics
• Public URL: https://hull-repository.worktribe.com/output/378963
• Publisher URL: http://pubs.rsc.org/en/content/articlelanding/2015/ce/c5ce01286d#!divAbstract
• Additional Information: : This document is CrossCheck deposited; : Supplementary Information; : Crystal Structure Data; : Graeme M. Day (ORCID); : Graeme M. Day (ResearcherID); : The Royal Society of Chemistry has an exclusive publication licence for this journal; OPEN ACCESS: This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0); : Received 2 July 2015; Accepted 12 August 2015; Accepted Manuscript published 12 August 2015; Advance Article published 19 August 2015; Version of Record published 16 September 2015