Non-covalent interaction in metal cation-directed assembly of supramolecular architectures: Synthesis, characterization and crystal structures

Three new complexes [Zn(NCS)2L2] (1), [Hg(SCN)2L2] (2) and [Mn(NCS)2L4] (3), have been synthesized by the self-assembly of 4-imidazolychalcone (abbreviated as L) with M(SCN)2 (M = Hg2+, Zn2+, Mn2+). The complexes have been characterized by spectroscopic and crystallographic methods. 1H NMR spectra of complexes 1–3 present that metal ions have effect on the chemical shifts of protons of coordinated groups. Three complexes illustrate different molecular structures due to the different coordinated modes of the metal ions. In the title complexes, the coordination geometries of Zn, Hg and Mn ions are tetrahedral N4, N2S2 and octahedral N6, respectively. Finally, hydrogen bonding interactions assemble the different coordination units into higher-dimensional frameworks. The results show that the metal ion and weak non-covalent interactions play important roles in the construction of the final supramolecular structures.

Graphical abstractThree different structural supramolecular complexes based on the reaction of 4-imidazolychalcone and M(SCN)2 (M = Hg2+, Zn2+, Mn2+) were synthesized by self-assembling. The complexes have been characterized by spectroscopic and crystallographic methods. 1H NMR spectra of complexes 1–3 present that metal ions have effect on the resonances of the protons of coordinated groups. The results show that the coordination geometries of Zn, Hg and Mn ions are tetrahedral N4, N2S2 and octahedral N6, respectively. The complexes illustrate different molecular structures due to the different coordinated modes of the metal ions. Finally, higher-dimensional supramolecular structures are formed through different weak non-covalent interactions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlight► A new ligand containing imidazolyl and carbonyl groups was synthesized and fully characterized. ► Three complexes based on reaction of the ligand and M(SCN)2 (M = Hg2+, Zn2+, Mn2+) were synthesized. ► The complexes were characterized by spectroscopic and crystallographic methods. ► 1H NMR spectra show metal ions have effect on the resonances of the protons of coordinated groups. ► Higher-dimensional structures are formed through coordinate bonds and weak non-covalent forces.