Synthesis and X-ray crystal structure of [(C 5 Me 5 ) 2 Sm] 2 C 4 Ph 2 , a samarium η 2 -complex derived from an alkyne

(C5Me5)2Sm(thf)2(thf = tetrahydrofuran) reacts with PhCCCCPh to form [(C5Me5)2Sm]2C4Ph2 which is found by X-ray crystallography to have η2-co-ordination of Sm3+ to the carbon–carbon multiple bonds.