Tris[(pentafluorophenyl)trimethylsilylamido](tetrahydrofuran)samarium(III)

Abstract

In the title complex, [Sm(C(9)H(9)F(5)NSi)(3)(C(4)H(8)O)], the Sm metal center is coordinated in a highly distorted tetrahedral geometry by the three N atoms of the amido ligands and by the O atom of the tetrahydrofuran ligand. Principal bond lengths include: Sm-N 2.299 (4), 2.339 (4) and 2.366 (4) A, and Sm-O 2.446 (3) A, close Sm. F contacts of 2.536 (3) and 2.556 (3) A, and an 'agostic' Sm.C interaction of 3.154 (4) A.

Lutetium Alkyls Supported by a Dearomatized and Functionalized Terpyridine Ligand: Preparation of Fluorinated Anilide Complexes

“…The terminal Lu−N anilide bond has a distance of 2.244(5) Å, which is slightly longer than those reported for other lutetium anilide complexes , and is likely a consequence of the electron-withdrawing pentafluorophenyl group on the amide ligand. There are only a handful – of structurally characterized lanthanide complexes supported by fluorinated amide ligands: (η-C 6 H 5 Me)Nd[N(C 6 F 5 ) 2 ] 3 , Sm[N(H)C 6 F 5 ] 3 (THF) 3 , and Sm[N(SiMe 3 )(C 6 F 5 )] 3 . However, unlike these Sm and Nd complexes, which all exhibit metal−fluorine interactions, the closest Lu−F distance in 7 is 2.943(4) Å, which is longer than the sum of the ionic radii of both lutetium (0.861 Å) and fluorine (1.285 Å) .…”

Electrophilic Ln(III) Cations Protected by C–F → Ln Interactions and Their Coordination Chemistry with Weak σ- and π-Donors

“…In order to access more electrophilic cations with accessible coordination sites for use in catalysis, reported efforts have included the preparation of lanthanide complexes with hemilabile donor groups, such as Nheterocyclic carbenes. 8 Metal−fluorine interactions have been widely observed for electron-deficient metal ions with organic C−F moieties, 9−11 including examples of actinide complexes 12−14 and lanthanide alkoxides, 15 thiolates, 16−19 amides, 20,21 diaminates, 22−24 aluminates, 25 organolanthanide complexes, 26,27 and a lanthanum cage complex. 28 Notably, Watkin and co-workers reported several lanthanide-fluorinated amide complexes bearing multiple weak interactions, including agostic interactions, η 6 -arene coordination, and Ln−F interactions.…”

“…28 Notably, Watkin and co-workers reported several lanthanide-fluorinated amide complexes bearing multiple weak interactions, including agostic interactions, η 6 -arene coordination, and Ln−F interactions. 20,21 Also, Gade and co-workers demonstrated the use of labile C−F → Zr moieties in an adaptive framework to accommodate the steric demands of small (A) or large (B) donor groups. 29−31 In a previous contribution, 14 we demonstrated that dative C−F → U interactions could be used to direct the coordination geometry around a uranium(IV) center into a unique pseudo-square planar geometry.…”

“…Metal–fluorine interactions have been widely observed for electron-deficient metal ions with organic C–F moieties, − including examples of actinide complexes − and lanthanide alkoxides, thiolates, − amides, , diaminates, − aluminates, organolanthanide complexes, , and a lanthanum cage complex . Notably, Watkin and co-workers reported several lanthanide-fluorinated amide complexes bearing multiple weak interactions, including agostic interactions, η 6 -arene coordination, and Ln–F interactions. , Also, Gade and co-workers demonstrated the use of labile C–F → Zr moieties in an adaptive framework to accommodate the steric demands of small ( A ) or large ( B ) donor groups. − In a previous contribution, we demonstrated that dative C–F → U interactions could be used to direct the coordination geometry around a uranium(IV) center into a unique pseudo-square planar geometry. The C–F → U interactions also contributed to the stabilization of an otherwise reactive U III complex, U[N(C 6 F 5 ) 2 ] 3 (THF) 2 .…”

Untitled

“…96 Refluxing [Ln 3 (OBu t ) 9 (Bu t -OH) 2 ] (Ln = La, Nd or Yb) in toluene gives 97 104 [Sm{N(C 6 F 5 )(Si-Me 3 )} 3 (thf)] 3 has distorted tetrahedral co-ordination of samarium but with additional close Sm…F contacts and an 'agostic' Sc…C contact. 105 The structure of [Sm{N(SiHMe 2 ) 2 } 3 (thf) 2 ] has been reported: it is TBPY with axial thf ligands. 106 [Y{N(SiHMe 2 ) 2 } 3 (thf) 2 ] readily reacts with p-tert-butylcalix [4]arene at room temperature exchanging all the amide ligands and forming a dimeric calix [4]arene complex.…”