Synthesis and Characterization of Nickel(II) Complex Containing 2‐(t‐Butylaminomethyl)pyrrole

Two aminopyrroles, 2‐(t‐butylaminomethyl)pyrrole ( HL1 ) and 2, 5‐di(t‐butylaminomethyl)pyrrole ( HL2 ), were synthesized and the hydrogen‐bond interactions were observed in the single‐crystal X‐ray structures of HL1 ·HCl and HL2. Bis2‐(t‐butylaminomethyl)pyrrole]nickel( II ) Ni(L1) ₂] was prepared by treatment of the NiCl₂ with 2 equiv. of mono‐deprotonated HL1 in THF solvent. The solid‐state structure of Ni(L1) ₂ shows the N₄‐coordinated nickel atom, with a geometry corresponding to a square‐planar structure, in which two intramolecular C‐H···Ni interactions are present at the axial positions with contact distances of 2.77 Å. The complex displays an irreversible reduction response at ?0.66 V (vs. Fc⁺/Fc) in CH₃CN. Furthermore, ¹H, ¹³C‐HSQC NMR experiments performed at room temperature revealed that the two methylene protons of the chelating L1^?1 are chemically nonequivalent and one of them is coupled to the amino proton. The coupling constants (J_HH') observed are close to the values predicted from the vicinal Karplus correlation diagram.