Citrulline (C6H13N3O3) is a non-protein amino acid found in watermelon. In physiological conditions, it is almost entirely present as a zwitterion, so its carboxylic and amine groups can act as Lewis donors, chelating metallic cations. In addition, Citrulline possesses a terminal ureide group of the aliphatic chain, which appears to be non-innocent. Although Citrulline is similar to other classical amino acids, only one coordination complex has been reported in the Cambridge Crystallographic Database. As part of our search for Casiopeina® analogs, we synthesized and characterized the copper bis-citrullinato complex, [Cu(Citr)2]n. The compound was described using UV-Vis, Infrared, and Raman spectroscopy, together with single-crystal X-ray diffraction. Computational tools were also used. The optimized structure, MEP map, IR and Raman spectra, and 1H and 13C chemical shifts were obtained with functional mPW1PW91 using 6-31G(d) basis set for N, O, C, and H atoms, and LANL2DZ basis set and ECP=LANL2DZ for the Cu atom. TD-mPW1PW91 calculations generated the UV-Vis spectrum. Finally, AIM and Hirshfeld surface analysis were used to examine non-covalent interactions. Previous investigations suggest Casiopeina®-like complexes can interact with DNA/RNA, creating potential anticancer chemicals. The [Cu(Citr)2]n complex’s polymeric nature and insolubility make it difficult for such purposes. However, the facile synthesis of D-Citrulline could be a novel way to find new applications for this interesting amino acid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.