Synthesis, spectral characterisation, crystal structure and Hirshfeld surface analysis of a dinuclear zinc(II) complex with a bis(imine)pyrrole ‘clamp’ ligand

The tridentate nitrogen-containing pincer ligand, (1H-pyrrole-2,5-diyl) bis(methanyliden) bis(2,6-diisopropylaniline) (L), was synthesised in 81% yield by the condensation of 1H-pyrrole-2,5-dicarbaldehyde with 2,6-diisopropylaniline. Its deprotonation, followed by reaction with zinc(II) chloride, led to the isolation of a dinuclear zinc complex, (L)Zn₂(µ-Cl)Cl₂, with a yield of 75%. Spectroscopic characterisation by NMR (¹H and ¹³C) confirms the desymmetrisation of the molecular environment resulting from coordination. X-ray diffraction analysis on a single crystal reveals that the complex crystallises in the triclinic system (space group P1). The Zn(II) metal centres adopt distorted coordination geometries, namely octahedral (ZnN₂Cl₄) and pentacoordinated (ZnN₂Cl₃). Finally, analysis of Hirshfeld surfaces and 2D fingerprints highlights the predominance of H•••H dispersive interactions (73.3 %), supplemented by secondary C–H•••π (14.5 per cent) and C–H••• Cl (10.2 %), which contribute to the cohesion of the crystal structure.