Structural characterization, spectroscopic properties, and Hirshfeld surface analysis of two copper(II) complexes with 3,14-dimethyl and 3,14-diethyl-2,6,13,17-diazadiazoniatricyclo[16.4.0.07,12]docosa-2,13-diene

Abstract

Herein, two unsaturated macrocyclic copper(II) complexes, namely, [CuLA(ClO4)2] (1) [LA = 3,14-dimethyl-2,6,13,17-diazadiazoniatricyclo[16.4.0.07,12]docosa-2,13-diene) and [CuLB(ClO4)]ClO4 (2) (LB = 3,14‑diethyl-2,6,13,17-diazadiazoniatricyclo[16.4.0.07,12]docosa-2,13-diene), were synthesized. The complexes were characterized by single-crystal X-ray determination and physico-chemical methods. Complex 1 crystallized in the monoclinic P21/n space group with Z = 2, while complex 2 crystallized in the monoclinic P21/c space group with Z = 4. The asymmetric unit of complex 1 contained one half of the [CuLA]2+cation and a single perchlorate anion, whereas complex 2 comprised a single [CuLB(ClO4)]+ cation and one doubly disordered perchlorate anion. The Cu(II) ion in complex 1 adopted a six-coordinated tetragonal geometry coordinated by four N atoms of the macrocyclic ligand LA [Cu–Namine 2.000 (2) Å and Cu–Nimine 1.962 (3) Å] and two axial perchlorate O atoms [Cu–O 2.6736 (4) Å], while the Cu(II) ion in complex 2 adopted a five-coordinated square pyramidal geometry coordinated by four N atoms of LB [mean Cu–Namine 1.9892 (17) Å and Cu–Nimine 1.9915 (18) Å] and an apical perchlorate O-atom [Cu–O 2.6318 (5) Å]. The crystals were stabilized by hydrogen bonds involving the secondary amine NH groups of the macrocycles and O atoms of the perchlorate groups. Hirshfeld surface analysis with 2D fingerprint plots revealed that the H⋯H and O⋯H interactions in both complexes 1 and 2 were the main intermolecular interactions.