Unprecedented reaction of bridged bis(guanidinate) lanthanide complexes: sterically induced deprotonation

作者：Wang Chuanyong; Zhang Xingmin; Xue Mingqiang^*; Zhang Yong; Shen Qi

来源：Dalton Transactions, 2013, 42(19): 7009-7018.

DOI：10.1039/c3dt32882a

Reaction of LnCl(3) with a lithium salt of bridged bis(guanidinate) bearing a rigid naphthalene linker [Li-2{LH2}(2)Li-2] (LH2 = 1,8-C10H6{NC((NPr)-Pr-i)(NHiPr)}(2)) (1), which was synthesized by the reaction of 1,8-diaminonaphthalene with 2 equiv. of (BuLi)-Bu-n, followed by treatment with 2 equiv. of N,N'-diisopropylcarbodiimide, yielded the chlorides [LnCl{LH2}] (Ln = Yb (2), Y (3)) in good yields. Metathesis reaction of 2 and 3 with NaN(SiMe3)(2) did not afford the corresponding amide complexes, but the deprotonation products of [Ln{LH}](2) (LH = 1,8-C10H6{NC((NPr)-Pr-i)((NHPr)-Pr-i)}{NC((NPr)-Pr-i)(2)}; Ln = Yb (4), Y (5)) were isolated instead. The LH in 4 and 5 both act as a bridging ligand binding to two metals in a mu-eta(1):eta(2):eta(2) fashion, and the re-arrangement of LH occurred during the reaction. The size of the amido group was found to have a great influence on the outcome of the metathesis reaction. Reaction of 2 with bulky NaNH((C6H3Pr2)-Pr-i-2,6) afforded 4 as the only product, whereas the same reaction with less bulky LiNH(C6H4Cl-4) and LiNH(C6H4CH3-4) led to the corresponding amides, [Yb{LH2}(NHC6H4Cl-4)](2) (6) and [Yb{LH2}(NHC6H4CH3-4)](2) (7), respectively. The re-arrangement of ligands was also observed in both cases. A possible pathway for the deprotonation of LH2 was discussed. Molecular structures of 1-7 were determined by X-ray single crystal analysis.

• 出版日期2013
• 单位苏州大学