[{Re6Q8}(SO3)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 Gd3+ Ions

Konstantin A Brylev; Bulat S Akhmadeev; Julia G Elistratova; Irek R Nizameev; Aidar T Gubaidullin; Kirill V Kholin; Ilya V Kashnik; Noboru Kitamura; Sung-Jin Kim; Yuri V Mironov; Asiya R Mustafina

doi:10.1021/acs.inorgchem.9b02346

[{Re₆Q₈}(SO₃)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 Gd³⁺ Ions

Inorg Chem. 2019 Dec 2;58(23):15889-15897. doi: 10.1021/acs.inorgchem.9b02346. Epub 2019 Nov 20.

Authors

Affiliations

¹ Nikolaev Institute of Inorganic Chemistry SB RAS , 3 Acad. Lavrentiev Ave. , 630090 Novosibirsk , Russian Federation.
² Novosibirsk State University , 2 Pirogova Str. , 630090 Novosibirsk , Russian Federation.
³ Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center , Russian Academy of Sciences , 8 Arbuzov str. , 420088 Kazan , Russian Federation.
⁴ Kazan (Volga region) Federal University , Kremlyovskaya str., 18 , 420008 Kazan , Russian Federation.
⁵ Department of Chemistry, Faculty of Science , Hokkaido University , 060-0810 Sapporo , Japan.
⁶ Department of Chemistry and Nano Science , Ewha Womans University , 03760 Seoul , Korea.

PMID: 31746193
DOI: 10.1021/acs.inorgchem.9b02346

Abstract

New octahedral rhenium cluster complexes [{Re₆Q₈}(SO₃)₆]^10- (Q = S or Se) were synthesized starting from [{Re₆Q₈}(H₂O)₄(OH)₂]·12H₂O. 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_x[{Re₆Se₈}(SO₃)₆]_y)^n- into a nanoparticulate form even at x = 1 and y ≥ 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_xGd_y[{Re₆Q₈}(SO₃)₆]-based colloids with the magnetic relaxivity values of r₁₍₂₎ = 21.0(24.1) and r₁₍₂₎ = 25.9(29.8) mM^-1 s^-1 for the {Re₆S₈}²⁺ and {Re₆Se₈}²⁺ derivatives, respectively.