Formation of a cyclooctatetraenylsamarium(III) inverse sandwich that ring-opens tetrahydrofuran.

Reductive trapping of the cyclooctatetraenyl dianion (COT2-) by treatment of [Sm(DippForm)2(thf)2] (DippFormH = N,N'-bis(2,6-diisopropylphenyl)formamidine; thf = tetrahydrofuran) with 1,3,5,7-cyclooctatetraene (C8H8) in toluene yields an inverse sandwich dinuclear complex [Sm2(DippForm)4(COT)] (1), but [Sm(DippForm)(COT)(thf)2] (2) and [Sm(DippForm)2(O-C4H8-DippForm)(thf)] (3) in thf, and 1 yields 2 and 3 on treatment with thf.

3d-4f heterometallic complexes by the reduction of transition metal carbonyls with bulky LnII amidinates.

The redox chemistry between divalent lanthanide complexes bearing bulky amidinate ligands has been studied with 3d transition metal carbonyl complexes (iron and cobalt). The reaction of [(DippForm)2SmII(thf)2] (DippForm = N,N'-bis(2,6-diisopropylphenyl)formamidinate) with [Co2(CO)8] resulted in the formation of a tetranuclear Sm-Co complex, [{(DippForm)2SmIII(thf)}2{(µ-CO)2Co(CO)2}2]. The product of the reaction of [(DippForm)2YbII(thf)2] and [Co2(CO)8] gives the dinuclear Yb-Co complex [{(DippForm)2YbIII(thf)}{(µ-CO)Co(CO)3}] in toluene. The reaction of [(DippForm)2SmII(thf)2] was also carried with the neighbouring group 8 carbonyl complexes [Fe2(CO)9] and [Fe3(CO)12], resulting in a pentanuclear SmIII-Fe complex, [{(DippForm)2SmIII}2{(µ3-CO)2Fe3(CO)9}], featuring a triangular iron carbonyl cluster core.