[{Re 6 Q 8 }(SO 3 ) 6 ] 10– (Q = S or Se): Facile Synthesis and Properties of the Most Highly Charged Octahedral Cluster Complexes and High Magnetic Relaxivity of Their Colloids with Gd 3+ Ions

• Published in: Inorganic chemistry Vol. 58; no. 23; pp. 15889 - 15897
• Main Authors: Brylev, Konstantin A., Akhmadeev, Bulat S., Elistratova, Julia G., Nizameev, Irek R., Gubaidullin, Aidar T., Kholin, Kirill V., Kashnik, Ilya V., Kitamura, Noboru, Kim, Sung-Jin, Mironov, Yuri V., Mustafina, Asiya R.
• Format: Journal Article
• Language: English
• Published: United States 02.12.2019
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b02346

New octahedral rhenium cluster complexes [{Re Q }(SO ) ] (Q = S or Se) were synthesized starting from [{Re Q }(H O) (OH) ]·12H O. The complexes were crystallized as sodium salts and characterized by X-ray single-crystal diffraction and elemental analyses, IR, UV/vis and luminescence spectroscopies. Magnetic relaxation data demonstrate the complex formation of the cluster units with gadolinium ions. The analysis of the magnetic relaxation rates measured at various Gd:cluster ratios and different concentrations revealed the conversion of the aggregates (Gd [{Re Se }(SO ) ] ) into a nanoparticulate form even at = 1 and ≥ 1. Thus, the self-assembly of the cluster units into the nanoparticles is greatly facilitated by counterion binding with sodium cations. The concentration conditions were optimized for the formation and hydrophilization of Na Gd [{Re Q }(SO ) ]-based colloids with the magnetic relaxivity values of = 21.0(24.1) and = 25.9(29.8) mM s for the {Re S } and {Re Se } derivatives, respectively.