Alkali metal complexes of an unsymmetrical imino-phosphanamidinate (N-P-N) ligand

The syntheses and characterization of alkali metal complexes of an unsymmetrical monoanionic imidazolin-2-imino-phosphanamidinate ligand, {(NHIP)-P-Dipp(Ph)N(Dipp)}(-) {L}(-) [Dipp = 2,6-diisopropylphenyl] is reported. The protio-ligand [(NHIP)-P-Dipp(Ph)NH(Dipp)] (LH) was obtained by the reaction of N-heterocyclic imine (NHI) and [PhP(Cl)NHDipp] in the presence of Et3N in toluene at room temperature. The lithium complex [{(NHIP)-P-Dipp(Ph)N(Dipp)}Li(OEt2)] (1) (Et = ethyl) was synthesized by the reaction of the protio ligand LH and one equivalent LiCH2SiMe3 in diethyl ether at room temperature. The reaction of sodium or potassium hexamethyldisilazide [MN(SiMe3)(2)] (M = Na or K) with LH in 1:1 molar ratio yielded corresponding alkali metal complexes [{(NHIP)-P-Dipp(Ph)N(Dipp)}Na(THF)] (2) and [{(NHIP)-P-Dipp(Ph)N(Dipp)}K(THF)(2)] (3) respectively in good yield. The molecular structures of the protio-ligand LH and alkali metal complexes 1 and 3 were established by single-crystal X-ray diffraction analysis. In the solid-state structures of 1 and 3, the lithium and potassium ions are kappa(2) bonded to the monoanionic ligand moiety through the imine nitrogen and phosphanamidinate nitrogen atoms. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The synthesis and characterization of alkali metal complexes of an unsymmetrical monoanionic imidazolin-2-imino-phosphanamidinate ligand were reported. The structures of lithium, sodium, and potassium complexes were established using single-crystal X-ray diffraction analysis, showing kappa(2) bonding to the ligand moiety.