Europium-151 and iron-57 nuclear resonant vibrational spectroscopy of naturally abundant KEu(III)Fe(II)(CN) 6 and Eu(III)Fe(III)(CN) 6 complexes

• Published in: Dalton transactions : an international journal of inorganic chemistry 2022-11, Vol.51 (46), p.17753-17761
• Main Authors: Wang, Hongxin, Huang, Songping D, Yan, Lifen, Hu, Michael Y, Zhao, Jiyong, Alp, Ercan E, Yoda, Yoshitaka, Petersen, Courtney M, Thompson, Matthew K
• Format: Article
• Language: English
• Subjects: Contrast agents; Europium; Europium isotopes; Ferrous Compounds; Iron - chemistry; Iron 57; Iron cyanides; Magnetic resonance imaging; Nanoparticles; Spectrum Analysis
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/d2dt02600g

We have performed and analyzed the first combined Eu and Fe nuclear resonant vibrational spectroscopy (NRVS) for naturally abundant KEu(III)[Fe(II)(CN) ] and Eu(III)[Fe(III)(CN) ] complexes. Comparison of the observed Eu Fe NRVS spectroscopic features confirms that Eu(III) in both KEu(III)[Fe(II)(CN) ] and Eu(III)[Fe(III)(CN) ] occupies a position outside the [Fe(CN) ] core and coordinates to the N atoms of the CN ions, whereas Fe(III) or Fe(II) occupies the site inside the [Fe(CN) ] core and coordinates to the C atoms of the CN ions. In addition to the spectroscopic interest, the results from this study provide invaluable insights for the design and evaluation of the nanoparticles of such complexes as potential cellular contrast agents for their use in magnetic resonance imaging. The combined Eu and Fe NRVS measurements are also among the first few explorations of bi-isotopic NRVS experiments.