Erbium Mixed‐Ligand β‐Diketiminato‐Diamido Complex: Unusual Structure of Diamide Ligand

Abstract

AbstractA novel mixed‐ligand erbium complex [(NacNac)ErL(THF)] (1) containing two types of sterically hindered ligands ‐ monoanionic N‐mesityl substituted β‐diketiminate (NacNac=(MesN−C(Me)CHC(Me)‐NMes)−, Mes=2,4,6‐Me3C6H2) and dianionic modified diamide ligand with mesityls as the N‐aryl substituents (L=(MesN−C(H)(Me)‐C(=CH2)‐NMes)2−) ‐ was isolated from the salt metathesis reaction of [(NacNac)Er(THF)2] with potassium salt of doubly reduced diazabutadiene K2(DAD‐Mes2−) (DAD‐Mes=MesN=C(Me)‐C(Me)=NMes) prepared in situ. A solid‐state structure of 1 was determined by single‐crystal X‐ray diffraction and revealed unusual asymmetrical diamide ligand with sp3‐ and sp2‐hybridized carbon backbone atoms and exometallacyclic double carbon‐carbon bond. In spite of the energy preference of symmetrical form of diamide ligand Lsym (Lsym=(MesN−C(Me)=C(Me)‐NMes)2−) calculated by DFT asymmetrical form L was found as minor product in the mixture of dipotassium salts obtained by reduction of DAD‐Mes.