title: Insertion reactions of beta-diketiminate-stabilised calcium amides with 1,3-dialkylcarbodiimides.
abstract: A series of heteroleptic beta-diketiminate-stabilised calcium amides of the form [{ArNC(Me)CHC(Me)NAr}Ca{NR1R2}(THF)] (Ar = 2,6-diisopropylphenyl; R1 = H, R2 = Ar; R1 = H, R2 = CH2CH2OMe; R1 = R2 = Ph) react with 1,3-dialkylcarbodiimides, R3NCNR3 (R3 = Cy, iPr), to yield the corresponding insertion products [{ArNC(Me)CHC(Me)NAr}Ca{(R3N)2CNR1R2}(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 2 through 3 coordination, with varying degrees of delocalisation of the non-bound guanidinate nitrogen lone-pair across the -framework of the ligand. DFT computational studies have been conducted to address these variations in coordination behaviour.
authors.affiliation: Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London, UKSW7 2AZ.
authors.forename: Anthony G M
authors.initials: AG
authors.lastname: Barrett
authors.forename: Mark R
authors.initials: MR
authors.lastname: Crimmin
authors.forename: Michael S
authors.initials: MS
authors.lastname: Hill
authors.forename: Peter B
authors.initials: PB
authors.lastname: Hitchcock
authors.forename: Panayiotis A
authors.initials: PA
authors.lastname: Procopiou
mesh_terms: D000577:Amides / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D002234:Carbodiimides / Q000737:chemistry*; D019791:Guanidine / Q000737:chemistry; D007097:Imines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D000577:Amides; D002234:Carbodiimides; D007097:Imines; D009570:Nitriles; C542835:ketimine; D019791:Guanidine; D002118:Calcium