Two novel quinoline-decorated half-salamo-type Co(II) complexes: Synthesis, crystal structure, Hirshfeld surface analysis, DFT calculation and fluorescence properties

Self-assembly through a quinoline-decorated N3O donor half-salamo-type tetradentate ligand HL and coordinative preference of Co(II) ion, two novel Co(II) complexes [Co(L)Cl] (1) and [Co(L)(NCS)] (2) were synthesized and characterized. X-ray crystallography revealed that both complexes 1 and 2 have similar mononuclear structure, in which the five-coordinated Co(II) atoms are not only surrounded by the N3O cavity of the deprotonated ligand (L)(-) unit, but also coordinated with different Cl- and NCS- anions. For the involvement of different anions, the crystal structures of the two complexes exhibit intermolecular C-H center dot center dot center dot Cl and C-H center dot center dot center dot S hydrogen interactions in building supramolecular assemblies, respectively. The two complexes are stabilized by C-H center dot center dot center dot O, C-H center dot center dot center dot N, C-H center dot center dot center dot C, C-H center dot center dot center dot S bonds and C-H center dot center dot center dot Pi, Pi center dot center dot center dot Pi interactions. The spectral properties of the complexes were investigated through UV-Vis and fluorescence spectroscopy. In addition, the detailed analyses of Hirshfeld surfaces and fingerprint plots provide the basis of the intermolecular interactions in building crystal blocks.

Automated summary

Two novel Co(II) complexes were synthesized and characterized through self-assembly of a newly designed ligand HL and coordinative preference of Co(II) ion. The crystal structures of the complexes revealed their mononuclear structure with specific coordination patterns and intermolecular hydrogen interactions. The complexes exhibited stable structures supported by various bonding interactions. The spectral properties of the complexes were investigated, and the intermolecular interactions in the crystal blocks were analyzed.