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

Abstract

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. Bis[2-(t-butylaminomethyl)pyrrole]nickel(II) [Ni(L1) 2 ] was prepared by treatment of the NiCl 2 with 2 equiv. of mono-deprotonated HL1 in THF solvent. The solid-state structure of Ni(L1) 2 shows the N 4 -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. F c + /Fc) in CH 3 CN. Furthermore, 1 H, 13 C-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.