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Two derivatives of a new bis(pyrazolyl)carbazole pincer ligand H(CzPzR), R = iPr and Me, and their syntheses are reported. Lutetium dialkyl complexes of the ligand (CzPzR)Lu(CH2SiMe3)2, R = iPr and...

The synthesis of a pentadentate NNNNN bis(phosphinimine)carbazole pincer ligand bearing two pyrimidine N-aryl rings is reported. A dialkyl lutetium complex of the ligand, prepared by alkane elimination with Lu(CH2SiMe3)3(THF)2, was found to undergo an unusual transformation involving a double alkyl shift whereby the −CH2SiMe3 groups on the metal migrated to both pyrimidine rings. This migration afforded a final product that featured alkyl-functionalized, dearomatized ligand pyrimidine rings.

Reactivity involving metallacycle ring opening of ortho-metalated bis(phosphinimine)carbazolide complexes (LPh-κ3N,κ2CP-Ph)Lu(THF) (1a) and (LPipp-κ3N,κ2CP-Ph)Lu(THF) (1b); L = [1,8-(Ph2P═NAr)2dmc]; Ar = Ph (LPh), p-isopropylphenyl (LPipp); dmc = 3,6-dimethylcarbazolide) is described. Reaction of 1a,b with bulky anilines (2,4,6-trimethylaniline, MesNH2; 2,4,6-triisopropylaniline, TripNH2) promoted metallacycle ring opening of two ortho-metalated P-phenyl groups to liberate the bis(anilide) products (LPh-κ3N)Lu(NHMes)2 (2) and (LPipp-κ3N)Lu(NHTrip)2 (3). Regardless of the quantity of TripNH2 or MesNH2 utilized, double ring opening always prevailed to afford the bis(anilide) product, rather than the mono(anilide). In contrast, reaction of complex 1b with the bulkier reagent 2,4,6-tri-tert-butylaniline (Mes*NH2) only caused metallacycle ring opening of one ortho-metalated P-phenyl group, affording the mono(anilide) complex (LPipp-κ3N,κCP-Ph)Lu(NHMes*) (4) exclusively. Complex 4 rapidly undergoes an intramole...