Synthesis, Characterization, and Reactivity Studies of New Cyclam-Based Y(III) Complexes.

[(Bn 2 Cyclam)Y(N(SiMe 3 ) 2 )] was prepared by reaction of H 2 Bn 2 Cyclam with Y[N(SiMe 3 ) 2 ] 3 . The protonation of the macrocycle ligand in [(Bn 2 Cyclam)Y(N(SiMe 3 ) 2 )] is observed upon reaction with [HNMe 3 ][BPh 4 ] leading to the formation of [(HBn 2 Cyclam)Y(N(SiMe 3 ) 2 )][BPh 4 ]. DFT analysis of [(Bn 2 Cyclam)Y(N(SiMe 3 ) 2 )] showed that the HOMO is located on the anionic nitrogen atoms of the cyclam ring indicating that protonation follows orbital control. Addition of H 2 Bn 2 Cyclam and H 2 ( 3,5-tBu2 Bn) 2 Cyclam to a 1:3 mixture of YCl 3 and LiCH 2 SiMe 3 in THF resulted in the formation of [((C 6 H 4 CH 2 )BnCyclam)Y(THF)(µ-Cl)Li(THF) 2 ] and [Y{(η 3 - 3,5-tBu2 Bn) 2 Cyclam}Li(THF)], respectively. The reaction of H 2 3,5-tBu2 Bn 2 Cyclam with Y(CH 2 SiMe 3 ) 3 (THF) 2 was studied and monitored by a temperature variation NMR experiment revealing the formation of [( 3,5-tBu2 Bn 2 Cyclam)Y(CH 2 SiMe 3 )]. Preliminary catalytic assays have shown that [Y{(η 3 - 3,5-tBu2 Bn) 2 Cyclam}Li(THF)] is a very efficient catalyst for the intramolecular hydroamination of 2,2-diphenyl-pent-4-enylamine.