Unusual crystalline heterobimetallic trinuclear β-diketiminates [Yb{L(µ-Li(thf)}2] and [Yb{L′(µ-Li(thf)}2]·thf [L, L′ = {N(SiMe3)C(R)}2CH, R = Ph, C6H4Ph-4]Electonic supplementary information (ESI) available: NOE data for 1 and NMR data for 2. See http://www.rsc.org/suppdata/cc/b2/b203321f/

YbCl3 with successively 2KL or 2KL′ and then >2Li in thf yields crystalline [Yb{L(μ-Li(thf)}2] 1 or [Yb{L′(μ-Li(thf)}2].thf 2, characterised by X-ray, multinuclear NMR spectral and VT magnetic susceptibility data; 1 and 2 are best formulated as Yb(II) complexes having dianionic L2− or L′2− ligands, L or L′ = {N(SiMe3)C(R)}2CH (R = Ph or C6H4Ph-4).