Rare formyl-coordinated homotrinuclear copper(II) salamo-based N2O3-donor complex: Experimental and theoretical studies

A formyl-coordinated phenoxo-bridged homopolynuclear dimeric Cu(II) complex of a salamo-like N2O3-donor ligand, [(L)2Cu3(MeOH)2](ClO4)2, has been synthesized and characterized structurally. The weak interactions of the Cu(II) complex were studied via MEPs, IRI and Hirshfeld surfaces analyses, and the energy gaps and electronic properties of H2L and the Cu(II) complex were investigated through DFT & TD-DFT calculations. [Display omitted] •A rare trinuclear Cu(II) complex was synthesized and characterized structurally.•Both phenoxy and formyl oxygen atoms participate in coordination.•The weak interactions were studied via MEPs, IRI and Hirshfeld surfaces analyses.•The energy gaps and electronic properties were investigated through DFT & TD-DFT calculations. A formyl-included salamo-based N2O3-donor ligand (H2L) was synthesized, and has two cavities of N2O2 and O3. Coordination reactivity of the ligand H2L toward Cu(II) atoms can result in an unprecedented centrosymmetric sandwich-like homotrinuclear Cu(II) complex, [(L)2Cu3(MeOH)2](ClO4)2, here Cu1 lies in the N2O2 positions, Cu2 is surrounded at the O6 coordination sphere and bridged via two metalated [(L)Cu(MeOH)] units, and coordinates further with two oxygen atoms of formyl groups of another two ligand (L)2- moieties. Finally, the dimeric structure’s complex was elucidated by elemental analyses and infrared spectroscopy, and fluorescence behaviors of the formyl-included ligand and the title complex were investigated. The weak interactions of the title complex were studied via MEPs, IRI and Hirshfeld surfaces analyses. Finally, the energy gaps and electronic properties of H2L and the title complex were investigated through DFT & TD-DFT calculations.