Dibenzoazepine hydrazine is a building block for N -alkene hybrid ligands: exploratory syntheses of complexes of Cu, Fe, and Li.

The new hydrazine 5 H -dibenzo[ b , f ]azepin-5-amine (2) reacts with P- and Si-electrophiles via deprotonation to afford P(III)-, P(V)-, and TMS-hydrazides 3-8 and with carbonyl electrophiles via acid-free condensation to the N -substituted hydrazones 9-12 that are potential N -alkene ligands. While β-ketohydrazone 9 and α-dihydrazone 10 react with [Mes(Cu)] 4 , [Cu(NCCCH 3 ) 4 ] 2 PF 6 , and FeCl 2 (THF) 1.5 to afford complexes devoid of alkene interaction, [Cu(OTf)] 2 ·C 6 H 6 reacts with the α-keto hydrazone 11 or with N , N dimethyl-hydrazone 12 to form the neutral dimeric Cu(I) complex 18 with bridging Cu(I)-alkene interactions or the tetrahedral cationic complex 19 in which 12 binds as a bidentate hydrazone-alkene ligand, respectively. The surprising stability of the alkene coordination in complexes 18 and 19 prevents substitutions with, e.g. , PPh 3 .