Insertion reactions of beta-diketiminate-stabilised calcium amides with 1,3-dialkylcarbodiimides

摘要

A series of heteroleptic beta-diketiminate-stabilised calcium amides of the form [{ArNC(Me)CHC(Me)NAr}Ca{(NRR2)-R-1}(THF)] (Ar = 2,6- diisopropylphenyl; R-1 = H, R-2 = Ar; R-1 = H, R-2 = CH2CH2OMe; R-1 = R-2 = Ph) react with 1,3-dialkylcarbodiimides, (RN)-N-3= C= NR3 (R-3 = Cy, Pr-i), to yield the corresponding insertion products [{ArNC(Me)CHC(Me)NAr}Ca{((RN)-N-3)(2)(CNRR2)-R-1}( THF)] at room temperature in hydrocarbon solutions. These latter compounds contain both beta-diketiminate and guanidinate ligands bound to calcium. Solid- state data are consistent with the guanidinate ligands adopting a number of binding modes including kappa 2 through kappa(3) coordination, with varying degrees of delocalisation of the non-bound guanidinate nitrogen lone-pair across the pi-framework of the ligand. DFT computational studies have been conducted to address these variations in coordination behaviour.