Unusual crystalline heterobimetallic trinuclear β-diketiminates YbL (µ-Li (thf) 2 and YbL′ (µ-Li (thf) 2·thf L, L′ = N (SiMe3) C (R) 2CH, R = Ph, C6H4Ph-4Electonic 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 YbL (μ-Li (thf) 2 1 or YbL′ (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).