858656-55-0Relevant articles and documents
Reactivity of bulky formamidinatosamarium(II or III) complexes with C=O and C=S bonds
Deacon, Glen B.,Junk, Peter C.,Wang, Jun,Werner, Daniel
, p. 12553 - 12563 (2014)
The preparation of a new heterobimetallic samarium(II) formamidinate complex and selected reactions of samarium(II) complexes and one samarium(III) formamidinate complex with benzophenone or CS2 are discussed. Treatment of the tris(formamidinato)samarium(III) complex [Sm(DippForm)3] 1 (DippForm = N,N′-bis(2,6-diisopropylphenyl)formamidinate, (CH(NC6H3-iPr2-2,6)2) with potassium graphite in toluene yielded the dark brown heterobimetallic formamidinatosamarium(II)/potassium complex [KSm(DippForm)3]n 2. Divalent 2, a Lewis base solvent free homoleptic species, differs significantly from the related heteroleptic formamidinatosamarium(II) complex [Sm(DippForm)2(thf)2] 3 with respect to its constitution, structure, and reactivity toward benzophenone. While 2 reacts giving complex 1, the reaction of 3 with benzophenone generates the highly unusual [Sm(DippForm)2(thf){μ-OC(Ph)=(C6H5)C(Ph)2O}Sm(DippForm)2] (C6H5 = 1,4-cyclohexadiene-3-yl-6-ylidene) 4. The formation of 4 highlights a rare C-C coupling between a carbonyl carbon and the carbon at the para position of a phenyl group of the OCPh2 fragment. An analogous reaction of [Yb(DippForm)2(thf)2] gives an isostructural complex 4Yb. 3 reacts with carbon disulfide forming a light green dinuclear formamidinatosamarium(III) complex [{Sm(DippForm)2(thf)}2(μ-2(C,S):(S′,S″)-SCSCS2)] 5 through an unusual C-S coupling induced by an amidinatolanthanoid species giving the thioformylcarbonotrithioate ligand. The trivalent organometallic [Sm(DippForm)2(CCPh)(thf)] complex activates the C=O bond of benzophenone by an insertion reaction, forming the light yellow [Sm(DippForm)2{OC(Ph)2C2Ph}(thf)] 6 as a major product and light yellow unsolvated [Sm(DippForm)2{OC(Ph)2C2Ph}] 7 as a minor product. Molecular structures of complexes (2, 4-7) show that (N,N′) bonding between a DippForm and samarium atom exists in all compounds, but in 2, DippForm also bridges K and Sm by 1(N):2(N′) bonding and two 2,6-diisopropylphenyl groups are 6-bonded to potassium.
Steric control of the reduction of carbodiimides by samarium(II) and the synthesis of very crowded samarium(III) complexes
Cole, Marcus L.,Deacon, Glen B.,Forsyth, Craig M.,Junk, Peter C.,Polo-Ceron,Wang, Jun
, p. 6732 - 6738 (2010/08/21)
Reduction of N,N′-di(2,6-diisopropylphenyl)carbodiimide (DippNCNDipp) by [SmL2(thf)2] (1) (L = N,N′-bis(2,6- diisopropylphenyl)formamidinate, DippNC(H)NDipp) in PhMe gave [Sm(L) 3] (2) in good yield. An analogous reaction of 1 with N,N′-dimesitylcarbodiimide (MesNCNMes) gave [SmL2(MesNC(H)NMes) ] (3). In contrast, reduction of N,N′-dicyclohexylcarbodiimide (CyNCNCy) by 1 in PhMe gave mixture of products from which [SmL2(CyNC(CH 2Ph)NCy)] (4) and [SmL2(CyNC(H)NCy)] (5) were isolated by fractional crystallisation. Using thf as the reaction solvent, solely compound 5 was crystallised. Reactions of [Sm(L)2(CCPh)(thf)] (6) with the carbodiimides RNCNR (R = Cy, Mes) gave [Sm(L)2(RNC(CCPh)NR)] (R = Cy (7) or Mes (8)) which are analogues of 4. No reaction was observed between 6 and DippNCNDipp. The Royal Society of Chemistry 2010.
