Tetrametallic Divalent Samarium Cluster Hydride and Dinitrogen Complexes

Reduction of trivalent samarium complexes obtained via reaction of SmCl 3 (THF) 3 with the disodium salt of the dipyrrolide dianion [R 2 C(H 3 C 4 N) 2 ] 2 - (R = Ph, 1 / 2 −(CH 2 ) 5 −) were carried out with sodium in THF and under nitrogen. The two reactions respectively yielded the tetranuclear divalent hydride {Na(THF) 6 }{([Ph 2 C(C 4 H 3 N) 2 ]Sm) 4 (H)(THF) 2 } ( 1 ) and the tetranuclear dinitrogen complex {[(CH 2 ) 5 C(C 4 H 3 N) 2 ]Sm} 4 (THF) 2 (μ-N 2 )[Na(THF)] 2 ·2THF ( 2 ). Transmetalation of [(Me 3 Si)N] 2 Sm(THF) 2 with 1,1-dipyrrolylcyclohexane afforded the dinitrogen complex {[(CH 2 ) 5 C(C 4 H 3 N) 2 ]Sm} 4 (μ-N 2 )·0.5THF ( 3 ). Despite the different oxidation states of 2 and 3 and the presence/absence of alkali-metal cation the two complexes display the same N−N distance.