Rationalizing the Influence of Small-Molecule Dopants on Guanine Crystal Morphology
Many spectacular optical phenomena in animals are produced by reflective assemblies of guanine crystals. The crystals comprise planar H-bonded layers of π-stacked molecules with a high in-plane refractive index. By preferentially expressing the highly reflective π-stacked (100) crystal face and cont...
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Published in | Chemistry of materials Vol. 36; no. 18; pp. 8910 - 8919 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
24.09.2024
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Online Access | Get full text |
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Summary: | Many spectacular optical phenomena in animals are produced by reflective assemblies of guanine crystals. The crystals comprise planar H-bonded layers of π-stacked molecules with a high in-plane refractive index. By preferentially expressing the highly reflective π-stacked (100) crystal face and controlling its cross-sectional shape, organisms generate a diverse array of photonic superstructures. How is this precise control over crystal morphology achieved? Recently, it was found that biogenic guanine crystals are composites, containing high quantities of hypoxanthine and xanthine in a molecular alloy. Here, we crystallized guanine in the presence of these dopants and used computations to rationalize their influence on the crystal morphology and energy. Exceptional quantities of hypoxanthine are incorporated into kinetically favored solid solutions, indicating that fast crystallization kinetics underlies the heterogeneous compositions of biogenic guanine crystals. We find that weakening of H-bonding interactions by additive incorporation elongates guanine crystals along the stacking directionthe opposite morphology of biogenic crystals. However, by modulation of the strength of competing in-plane H-bonding interactions, additive incorporation strongly influences the cross-sectional shape of the crystals. Our results suggest that small-molecule H-bond disrupting additives may be simultaneously employed with π-stack blocking additives to generate reflective platelet crystal morphologies exhibited by organisms. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0897-4756 1520-5002 |
DOI: | 10.1021/acs.chemmater.4c01771 |