Abstract: A wide range of various stabilizing ligands is applied in the metalloorganic chemistry of lanthanides, which suits to the different aims. Depending on the nature of the ligand, coordination type, steric bulkiness, presence of redox active or chromophore groups, lanthanide complexes with them can be applied in material science, catalysis, they are of interest from the point of view of magnetic and luminescent properties. Thus, constructing and development of new ligands are of current interest even nowadays. Amidinates RC(NR')2 – are one of the most frequently used families of ligands in lanthanideorganic chemistry, side by side with the famous cyclopentadienyls. A closely related group of silanediamido ligands R2Si(NR')2 2– is known along them, but much less investigated due to a somewhat more complicated synthesis and a restricted air stability of silanediamines. Nevertheless, their higher negative charge (2–) and a heavier central Si arom replacing the C(R) fragment could be useful for the functional lanthanide complexes We investigated known silanediamides of type H2(ArNSiN) = SiMe2(HNAr)2 (Ar = Dipp, Mes), and supplemented them with new ones bearing chromophore groups (Ar = Pbt, Btd; Pbt = ophenylbenzotiazole, Btd = 2,1,3-benzotiadiazole). By their deprotonation followed by the salt metathesis with lanthanide(III) halides we obtained series of the complexes with lanthanides of the different ionic radii. For Dipp- and Mes- substituted ligands, the binuclear complexes [{Ln(ArNSiN)(thf)2}2(μ-Cl)2] were synthesized; also, a mononuclear complex [Y(DippNSiN)Cl(thf)3] and ate-complexes [{Ln(DippNSiN)(μ-Cl)(thf)(Li(thf)3)}2(μ-Cl)2] (Ln = Y, Tb) were structurally characterized. Pbt- and Btd- substituted ligands have a tendency to the formation of bis-ligand anionic complexes [Ln(ArNSiN)2]– because of the additional donor atoms of substituents, and the synthesis of mono-ligand complexes in this case appears challenging. The energy of the triplet levels of the ligands were experimentally determined by measuring the emission of the Gd complexes at 77 K. Dipp- and Mes- substituted ligands were found to exhibit a suitable antenna effect for the sensitization of the Tb3+ luminescence in the visible range with the energies of 2.05∙104 and 2.63∙104 cm–1, respectively. Pbt-substituted ligand, despite the promising bright emission of NH2Pbt, has a lower energy insufficient for the sensitization of the lanthanides emitting in the visible region, but may be suitable for the NIR region. Further studies are in progress.

Cite: Mironova O.A. , Bashirov D.A. , Sukhikh T.S. , Konchenko S.N. , Pushkarevskii N.A. , Lashchenko D.
Synthesis and photophysical properties of silanediamido complexes of lanthanides
The Sixth International Scientific Conference "Advances in Synthesis and Complexing" 26-30 Sep 2022