σ-Donor versus η6-π-Arene Interactions in Monomeric Europium(II) and Ytterbium(II) Thiolates − An Experimental and Computational Study

Abstract

Keywords: Ab initio calculations / Lanthanides / π interactions / S ligands / YtterbiumThe base-free, hydrocarbon-soluble complexes M(SAr*) 2 (4a: M = Eu, orange; 4b: M = Yb, purple; Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6-iPr 3 C 6 H 2 ) have been prepared by a protolysis reaction of the Grignard-analogous compound RLnI (R = 2-F 3 CC 6 H 4 ) with HSAr*. Compound 4b has been characterized by melting point, elemental analysis, 1 H, 13 C, and 171 Yb NMR, IR spectroscopy, UV/Vis spectrophotometry, mass spectrometry, and X-ray crystallography. Additionally, the purple Yb III complex YbI 2 (SAr*)(THF) 3 (3) and the yellow DME adduct Yb(SAr*) 2 (dme) 2 (5) have been synthesized and characterized by X-ray crystallography. The solid-state structures of 4a and 4b (as THF or benzene hemisolvates) show monomeric units with the metal atom bonded to two terminal

Novel Sterically Congested Monoorganobismuth(III) Compounds: Synthesis, Structure, and Bismuth−Arene π Interaction in ArBiXY (X, Y = Br, I, OH, 2,6-Mes2-4-t-Bu-C6H2PHO2)

“…Thus, there is no correlation of the energy barrier for rotation and the Bi−arene distance (Bi(1)−Ar cent[C(51)−C(56)] 3.522 Å, Bi(1)−Ar cent[C(21)−C(26)] 3.376 Å) observed in the solid state. It is interesting to note that in Yb(SAr*) 2 (Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6- i Pr 3 C 6 H 2 ) a similar intramolecular metal−arene π complexation was found and that the dynamic character of the metal−arene coordination is associated with an energy barrier of 54.3 kJ mol −1 based on variable-temperature NMR studies in methylcyclohexane solution . Theoretical studies on the model system Yb(SH) 2 (C 6 H 6 ) 2 gave a value of 31.5 kJ mol −1 (B3LYP) for benzene dissociation.…”

Developments in the Coordination Chemistry of Europium(II)

“…Thiolate-containing complex Eu(SAr*) 2 (THF) 0.5 ( 30 ), in which Ar* is 2,6-[2,4,6-( i Pr) 3 C 6 H 2 ] 2 C 6 H 3 , was prepared from Eu 0 , Ar*SH, and 2-iodobenzotrifluoride. [48] This thiolate complex is characterized by η 6 -π interactions of Eu 2+ with two o -2,4,6-triisopropylphenyl rings of the terphenyl groups, as evidenced by IR spectroscopy and X-ray crystallography. [48] Another example of a Eu 2+ -containing complex that shows η 1 -π interactions with Eu 2+ and was prepared from europium metal is Eu(Dpp)(THF) 2 ( 31 ), where Dpp is 2,6-Ph 2 C 6 H 3 .…”

“…[48] This thiolate complex is characterized by η 6 -π interactions of Eu 2+ with two o -2,4,6-triisopropylphenyl rings of the terphenyl groups, as evidenced by IR spectroscopy and X-ray crystallography. [48] Another example of a Eu 2+ -containing complex that shows η 1 -π interactions with Eu 2+ and was prepared from europium metal is Eu(Dpp)(THF) 2 ( 31 ), where Dpp is 2,6-Ph 2 C 6 H 3 . Complex 31 was synthesized from Eu 0 and DppI in THF and exhibits a distorted tetrahedral geometry with two aryl ligands and two THF molecules.…”

Lanthanide(III) 4,6-Dimethylpyrimidine-2-thionate Complexes as Efficient Catalysts for Isocyanate Cyclodimerization

“…In the past decades, the synthesis of lanthanide thiolate complexes has attracted much attention due to their interesting structures, luminescence properties, and potential applications in catalytic processes and the preparation of organic or organolanthanide complexes . So far, a number of these complexes with alkane- or arenethiolates , have been synthesized. Among them, the tendency for thiolates to serve as bridging ligands and for the lanthanide ions to maximize coordination numbers generally leads to the formation of oligomeric or polymeric lanthanide thiolate complexes unless the lanthanide ion is coordinated by strong donor molecules or very bulky thiolate ligands.…”