A Holmium(III) `Carbons Adjacent' Carborane Cluster, [Li(C₆H₁₆N₂)₂][Li₂(C₆H₁₆N₂)₂{HoCl₂(C₈H₂₂B₄Si₂)₂}].0.5C₆H₆

The title compound, bis­[(N,N,N',N'- tetramethylethylenediamine)lithium μ-{1,1′-commo-1,1′dichlorobis[2,3-bis(trimethylsilyl)-2,3-dicarba-1-holma-closo-heptaborato]}-1κ³H^4,4′5:2κ²H^4′,5′, 2κCl-bis[(N,N,N',N'- tetramethylethylenediamine)lithium] benzene hemisolvate, [Li(TMEDA)₂][{1-Cl-1-(μ-Cl)-2,2′,3,3′-(SiMe₃)₄– 5,6-[(μ-H)₂Li(TMEDA)]-4,4′,5′-[(μ-H)₃Li(TMEDA)]}-1,1′-commo-Ho(2,3-C₂B₄H₄)₂].0.5C₆H₆ (TMEDA = tetramethylethylenediamine), crystallized in a monoclinic space group P2₁/n. The structure of this cluster consists of an Ho^III `carbons- adjacent' carborane bent-sandwich complex in which two Cl⁻ ions are present, in different bonding environments, in the primary coordination sphere of the Ho atom giving a very distorted tetrahedral arrangement about the metal with the Ho—Cnt(1,2) = 2.378, 2.350 Å, Cnt(1)—Ho—Cnt(2) = 128.5°, Cnt(1)—Ho—Cl(1,2) = 107.9, 103.2°, Cnt(2)-Ho-Cl(1,2) = 110.6, 104.4°, and Cl(1)—Ho—Cl(2) = 97.17 (6)° (Cnt = C₂B₃ centroid). One of the exo-polyhedral Li(TMEDA) units is linked to both opposing C₂B₃ faces via three B-H_(terminal) bonds and the other interacts with only one of the C₂B₃ faces via two B-H_(terminal) groups with an additional linkage to the central Ho atom via an Ho-Cl—Li bridge.

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