Mono- and Disamarium Azacryptand Complexes: A Platform for Cooperative Rare-Earth Metal Chemistry.

Mono- (H 3 LSm) and disamarium complexes (LSm 2 ) were prepared by reaction of the azacryptand N[(CH 2 ) 2 NHCH 2 - p -C 6 H 4 CH 2 NH(CH 2 ) 2 ] 3 N (H 6 L) with 1 or 2 equiv of Sm[N(SiMe 3 ) 2 ] 3 , respectively. The disamarium complex features free coordination sites on both metal centers available for bridging ligands shielded by phenylenes from tetrahydrofuran (THF) coordination. The reaction of LSm 2 with KCN and 18-crown-6 yielded the adduct [LSm 2 -μ-η 1 :η 1 -CN][K(18-crown-6)(THF) 2 ] featuring a bridging cyanide. The complexes were characterized by crystallography, electrochemical analysis, NMR, and optical spectroscopy, and the effective magnetic moments were determined via the Evans method.