Molecular structure, spectroscopic properties, and Hirshfeld surface analysis of chlorobis(N-methyl-1,3-propanediamine)copper(II) tetrafluoroborate and azidobis(2,2-dimethyl-1,3-propanediamine)copper(II) azide

Two new copper (II) complexes, [Cu(N-Metn)2Cl]BF4 (1) and [Cu(Me2tn)2(N3)]N3 (2) (N-Metn = N-methyl-1,3-propanediamine; Me2tn = 2,2-dimethyl-1,3-propanediamine), have been prepared, fully characterized, and their structures established by X-ray single-crystal analysis from synchrotron diffraction data. For these complexes, the Cu(II) ions are five-coordinate in an axially elongated square-pyramidal environment, with the four amine N atoms at the equatorial positions and the Cl atom (1) or N atom of one azide (2) at an apical site. The CuN bond lengths for amine N atoms in the complex 1 (2.0198(13)-2.0735(12) A°) and complex 2 (2.0239(9)-2.0489(9) Å) are typical, but the axial ligands are coordinated with a CuCl bond length of 2.5962 (7) Å for complex 1, and the CuN (azido) bond length is 2.1990 (10) Å for complex 2, adopting square-planar geometry around the Cu(II) with four N atoms from two N-Metn or Me2tn ligands. The crystals are stabilized by a three-dimensional network of intermolecular hydrogen bonds that are formed between the primary and secondary amine groups of the N-Metn ligands, the Cl ligands, and the F atoms of BF4− anion in 1, and by the primary amine groups of the Me2tn ligands and the N atoms of the azido ligand and azide ion in 2. Hirshfeld surface analysis with 2D fingerprint plots revealed that the H⋯H, F⋯H, Cl⋯H contacts in 1 and the H⋯H and N⋯H contacts in 2 are the main intermolecular interactions. The electronic absorption and IR spectral properties are also discussed.