Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 20. Synthetic and Structural Studies on Sandwich Ln(III) Carborane Clusters. II (Ln(III) = Sm, Gd, Dy, Ho, Er)

Abstract

The room-temperature reactions of closo- exo-4,5-[(µ-H) 2 Li(TMEDA)]-1-Li(TMEDA)-2,3-(SiMe 3 ) 2 -2,3-C 2 B 4 H 4 with anhydrous LnCl 3 (Ln ) Sm, Gd, Dy, Ho, Er), in molar ratios of 2:1 in dry benzene (C 6 H 6 ), produced the sandwich paramagnetic species [Li(TMEDA 1), Gd (2), Dy (3), Ho (4), Er ( 5)) in yields of 65%, 88%, 71%, 90%, and 93%, respectively. The compounds were characterized by IR spectroscopy, magnetic susceptibility measurements, and single-crystal X-ray diffraction studies. Compounds 2 and 3 were further characterized by EPR spectroscopy, and compound 1 was also characterized by 1 H, 13 C, 11 B, and 7 Li NMR spectroscopy. All compounds are bent-sandwich complexes in which a Ln(III) atom is coordinated to two carborane ligands and two chloride ions. The room-temperature magnetic susceptibilities of 1-4 were found to be 1.1, 7.3, 9.4, and 10.1 µ B per metal atom, respectively. Experimental SectionMaterials. Benzene, N,N,N′,N′-tetramethylethylenediamine (TMEDA), and n-hexane were dried over NaH and Na metal and doubly distilled before use. All other solvents were dried over 4-8 Å molecular sieves (Aldrich) and were either saturated with dry argon or degassed before use. The syn

Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

“…As THF seems to be the source of the oxygen atom as well as of the methoxy group, the same reactions were carried out using the TMEDA- with additional Cl, LiCl, or solvent ligands, is bonded to two carborane units which are bridged by one Li(TMEDA). 185,[188][189][190] Repeated crystallization causes the loss of one LiCl(TMEDA) moiety. 185 A very similar structure is presented by the reac- …”

Synthesis and Structural Characterization of closo- and exo-nido-Lanthanacarboranes

“…Since then, they have published a series of papers describing the syntheses and structures of the sandwich and half-sandwich complexes of divalent and trivalent lanthanide metals (Sm, Yb, and Eu) with C 2 B 9 H 11 2- and C 2 B 10 H 12 2- ligands. − For example, reactions of Na 2 [C 2 B 9 H 11 ] with LnI 2 (Ln = Sm, Yb) in THF gave half-sandwich complexes of the type Ln(C 2 B 9 H 11 )(THF) 4 , followed by oxidation with [Tl(C 2 B 9 H 11 )] - to generate sandwich complexes of the general formula [Ln(C 2 B 9 H 11 ) 2 ] - . , The reactions of LnI 2 (Ln = Sm, Eu, Yb) with the larger C 2 B 10 H 12 2- were more complicated. Both polymeric and monomeric structures were obtained depending on both the nature of the lanthanide metals and the metal-to-ligand molar ratios employed in the reactions. , The smaller [(Me 3 Si) 2 C 2 B 4 H 4 ] 2- anion was introduced to organolanthanide chemistry by Hosmane and co-workers. − This anion reacted with mid- to late-lanthanide trichlorides to produce various types of lanthanacarboranes depending on both the solvents and the metal-to-carborane molar ratios used in the reactions. For instance, the sandwich species of the general formula [1-Cl-1-(μ-Cl)-2,2‘,3,3‘-(Me 3 Si) 4 -5,6-[(μ-H) 2 Li(TMEDA)]-4,4‘,5‘-[(μ-H) 3 Li(TMEDA)]-1,1‘- commo -Ln(2,3-C 2 B 4 H 4 ) 2 ] - were isolated in good yield from 1:2 (Ln to carborane) molar reaction stoichiometries in a TMEDA ( N,N,N‘,N‘ -tetramethylethylenediamine)/benzene solvent system .…”

“…Both polymeric and monomeric structures were obtained depending on both the nature of the lanthanide metals and the metal-to-ligand molar ratios employed in the reactions. , The smaller [(Me 3 Si) 2 C 2 B 4 H 4 ] 2- anion was introduced to organolanthanide chemistry by Hosmane and co-workers. − This anion reacted with mid- to late-lanthanide trichlorides to produce various types of lanthanacarboranes depending on both the solvents and the metal-to-carborane molar ratios used in the reactions. For instance, the sandwich species of the general formula [1-Cl-1-(μ-Cl)-2,2‘,3,3‘-(Me 3 Si) 4 -5,6-[(μ-H) 2 Li(TMEDA)]-4,4‘,5‘-[(μ-H) 3 Li(TMEDA)]-1,1‘- commo -Ln(2,3-C 2 B 4 H 4 ) 2 ] - were isolated in good yield from 1:2 (Ln to carborane) molar reaction stoichiometries in a TMEDA ( N,N,N‘,N‘ -tetramethylethylenediamine)/benzene solvent system . On the other hand, the results were quite different when THF was involved in the reactions, from which trinuclear lanthanacarborane clusters of the type {[η 5 -1-Ln-2,3-(Me 3 Si) 2 -2,3-C 2 B 4 H 4 ] 3 [(μ 2 -1-Li-2,3-(Me 3 Si) 2 -2,3-C 2 B 4 H 4 ) 3 (μ 3 -OMe)][(μ 2 -Li(C 4 H 8 O)] 3 (μ 2 -O)} were isolated …”

Main Group Multiple C–H/N–H Bond Activation of a Diamine and Isolation of A Molecular Dilithium Zincate Hydride: Experimental and DFT Evidence for Alkali Metal–Zinc Synergistic Effects

“…There are currently 147 compounds in the CCDB containing Li hydride contacts with their lengths spanning the wide range 1.607 166 –2.802 Å. 167 The average distance (2.044 Å) is comparable with those found in 7 . To the best of our knowledge there are no previously reported zinc μ 3 -hydride complexes.…”