410 ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2018, Vol. 44, No. 6, pp. 410–414. © Pleiades Publishing, Ltd., 2018. Original Russian Text © D.M. Roitershtein, M.D. Dobrokhodov, A.A. Vinogradov, M.E. Minyaev, K.A. Lyssenko, A.V. Churakov, N.P. Datskevich, I.V. Taidakov, I.E. Nifant’ev, 2018, published in Koordinatsionnaya Khimiya, 2018, Vol. 44, No. 3, pp. 206–210. Spontaneous Association of the Terbium Cyclopentadienyl Complexes under Controlled Hydrolysis D. M. Roitershtein a, b, *, M. D. Dobrokhodov a , A. A. Vinogradov a , M. E. Minyaev a , K. A. Lyssenko c , A. V. Churakov d , N. P. Datskevich e , I. V. Taidakov c, e , and I. E. Nifant’ev a, f a Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, 119992 Russia b Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, 119991 Russia c Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russia d Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, 119991 Russia e Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991 Russia f Moscow State University, Moscow, 119899 Russia *e-mail: roiter@server.ioc.ac.ru Received August 17, 2017 Abstract—Controlled hydrolysis of the terbium cyclopentadienyl complexes results in the formation of the heteroligand tetranuclear terbium complex [{Tb(η 5 -C 5 H 5 )} 3 {Tb(THF) 3 }(μ 3 -Cl)(μ 2 -Cl) 6 (μ 4 -O)] (I), the recrystallization of which from tetrahydrofuran (THF) gives solvatomorph I · 0.5THF (Ia). According to the X-ray structure analysis data (CIF files CCDC 1569329 (I) and 1569330 (Ia)), the complexes are tetrahedral with the μ 4 -bridging O 2– anion at the center of the tetrahedron. The cyclopentadienyl ligand in complex I is shown to act as an “antenna” providing luminescence of the complex. Keywords: rare-earth metals, X-ray structure analysis, luminescence, cyclopentadienyl ligand DOI: 10.1134/S1070328418060052 INTRODUCTION Cyclopentadienyl (Ср) complexes of rare-earth metals predominate in the organometallic chemistry of 4f elements from the middle of the 20th century when the first organolanthanide compounds, tris-Ср complexes [Ln(C 5 H 5 ) 3 ], have been discovered [1, 2]. Their heteroligand analogs, mono- and bis-Cp halide complexes of rare-earth metals [Ln(C 5 H 5 ) 2 Cl] 2 [3] and [Ln(C 5 H 5 )Cl 2 (THF) 3 ] 2 , were synthesized later [4]. In spite of considerable diversity of ligands in the modern chemistry of 4f elements, the Cp ligand and its substituted analogs still play the leading role in the organometallic chemistry of rare-earth elements [5, 6]. The development of the chemistry of Cp com- plexes of rare-earth metals is caused, to a high extent, by the possibility of relatively easy modification of the Cp ligand by the substitution of one or several hydrogen atoms of the five-membered ring. Signifi- cant changes in the steric hindrance of the ligand that occur during the substitution make it possible to pur- posefully change the properties of the organolantha- nide ligands, whose reactivity is considerably con- trolled, as was repeatedly mentioned, by the volume of the ligands and coordination saturation of the com- plex [7, 8]. One of specific features of the coordination and organometallic compounds of rare-earth metals is spontaneous association to form polynuclear com- plexes with bridging donor ligands between Ln 3+ cat- ions. The formation of these polynuclear complexes is due to a tendency of lanthanide to form complexes with a high coordination number of the central ion [9]. The formation of such structures is most characteristic of the complexes with carboxylate and alkoxide ligands [10, 11]. Nevertheless, polynuclear structures can be formed even for the tris-Cp complexes having no donor ligands. A combination of two factors, the steric hindrance of the ligand and the ionic radius of the metal changing with moving along the 4f series, leads to a change in the degree of association from the mononuclear [Ln(C 5 H 5 ) 3 ] (Ln = Yb) to coordination polymers [Ln(C 5 H 5 ) 3 ] ∞ (Ln = La, Pr, Nd) [6]. In this work, we report the possibility of the pur- poseful construction of tetranuclear structures of ter- bium Cp complexes with the Tb 4 tetrahedral frame- work by the controlled hydrolysis of the terbium Cp complexes.