Trivalent Lanthanide Compounds with Fluorinated Thiolate Ligands:  Ln−F Dative Interactions Vary with Ln and Solvent

Abstract

The fluorinated tris-thiolate compounds Ln(SC(6)F(5))(3) can be isolated as THF, pyridine, or DME coordination complexes. In THF, the larger Ce forms dimeric [(THF)(3)Ce(SC(6)F(5))(3)](2) (1) with bridging thiolate ligands, while the smaller lanthanides (Ln = Ho (2), Er (3)) form monometallic (THF)(3)Ln(SC(6)F(5))(3) compounds. There is a tendency for fluoride to coordinate to Ln throughout the lanthanide series (Ce-Er). The cerium compound 1 contains a pair of bridging thiolates connecting two eight-coordinate Ce(III) ions. Of the two terminal thiolates, only one exhibits a distinct Ce-F bond. In contrast, the Ho derivative (THF)(3)Ho(SC(6)F(5))(3) is a molecular compound in the solid state, with two monodentate thiolates and one thiolate that again coordinates through both S and F atoms. Incorporation of a stronger Lewis base reduces but does not necessarily eliminate the tendency to form Ln-F bonds. Structural characterization of the eight-coordinate (pyridine)(4)Sm(SC(6)F(5))(3) (4) reveals a single, clearly defined Ln-F interaction, while in (pyridine)(4)Yb(SC(6)F(5))(3) (5) there are no Yb-F bonds. In the structure of (DME)(2)Er(SC(6)F(5))(3) (6) the DME ligands completely displace F from the Er coordination sphere.

Intramolecular Metal–Fluorocarbon Coordination, CF Bond Activation and Lanthanoid–Fluoride Clusters with Tethered Polyfluorophenylamide Ligands

“…[10] The remaining two peaks may therefore represent ytterbiumA C H T U N G T R E N N U N G (III)-fluoride species. Comparable data for lanthanoid fluorides are rare, but [La(L) 2 …”

“…In most cases the polyfluoroaryl group is coordinated both through fluorine and another donor atom, for example, 1) carbon (C,F bridging [1] and C,F chelating [2][3][4][5] ) in polyfluorophenyl-rare-earth compounds, 2) nitrogen in polyfluorophenylamides, [6][7][8] 3) oxygen in polyfluorophenolates [9] and 4) sulfur in polyfluorothiolates. [10][11][12] In addition, BA C H T U N G T R E N N U N G (C 6 F 5 ) 4 À and related anions can act as C(Ar)-F-Ln donors, often chelating through two fluorine atoms. [13][14][15] Even discrete fluorine-bonded complexes between [ScA C H T U N G T R E N N U N G (C 5 Me 5 ) 2 ]…”

Synthesis and Structures of the First Cationic Perfluoroaryllanthanoid(II) Complexes

“…[11] The bulkiness of the N(SiMe 3 ) 2 groups leads to a large N-Yb-N angle and correspondingly narrow C-Yb-C angle (Table 3). The two C 6 F 5 groups are asymmetrically bound to Yb, each having one of the ortho-fluorines tilted toward the metal (as evidenced by narrow C-C-Yb angles 4 ] intramolecular LnÀF bonds are in the range 2.579(2)-2.749(2) ä, [31] well (1) Yb (2)ÀC (25) 2.569(9) 403(4), 2.158(3) ä). [32] Arguably, the YbÀs-aryl linkage in the latter is lengthened due to the bulky 2,6-mesityl substituents, and indeed this and the current YbÀC bond lengths are at the long end of the range for the terminal unsubstituted Ph groups of six-coordinate [YbPh 3 (thf) 3 ] [14,33] and [Yb III Ph 2 (thf)(m-Ph) 3 Yb II (thf) 3 ] (2.39(6)±2.46(4) ä) [34] despite the higher coordination numbers of the last two compounds.…”

1D‐Polyoxometalate‐Based Composite Compounds − Design, Synthesis, Crystal Structures, and Properties of [{Ln(NMP)6}(PMo12O40)]n (Ln = La, Ce, Pr; NMP = N‐methyl‐2‐pyrrolidone)

“…The average bond length for all PrϪO bonds is 2.429 Å , which is 0.099 Å longer than the mean Pr(1)ϪO bond length (2.393 Å ) of [Pr 2 (bbpen) 2 -(NO 3 )(H 2 O)]NO 3 ϫCH 3 OH, [28] in which the coordination number of the Pr 3ϩ ion is 8 and the coordination polyhedron around the Pr 3ϩ ion is a distorted cube. The average bond length for all CeϪO bonds is 2.47 Å , which is 0.064 Å shorter than the mean Ce(1)ϪO bond length of 2.53 Å in [(THF) 3 Ce(SC 6 F 5 ) 3 ] 2 , [29] in which the coordination number of the Ce 3ϩ (1) ion is 8. The variation of the LnϪO average bond separations along the La, Ce, and Pr series (LaϪO Ͼ CeϪO Ͼ PrϪO) is consistent with the effects of the lanthanide contraction (ionic radius: La 3ϩ Ͼ Ce 3ϩ Ͼ Pr 3ϩ ).…”