Coordination assemblies of rigid–flexible 1,3-bis(5-(pyridine-2-yl)-1,2,4-triazole-3-yl)propane ligands with MCl2 (M = Fe, Co, Cu or Zn): structural diversity and mass spectra

Reactions of the rigid–flexible N-heterocycle 1,3-bis(5-(pyridine-2-yl)-1,2,4-triazole-3-yl) propane (H2L) with MCl2 (M = Fe, Co, Cu or Zn) gave coordination complexes, {[Fe 2 III Cl4(H2L)2]·2Cl}·EtOH·H2O (1), {[Co3Cl5(HL)]·H2O} n (2), {[Co4Cl4(H2L)2(H2O)4]·[CoCl4]2}·H2O (3), [Cu2Cl3(HL)(H2O)]6·5H2O (4), [Cu 2 II CuICl4(HL)] n (5), {[Zn2Cl2(L)H2O]·H2O} n (6) and [Zn4Cl6(HL)2] (7), which have been characterized by single-crystal X-ray diffraction. Structural analysis reveals that the pyridine triazole ligand attains versatile coordination modes in these complexes. Complexes 1, 3, 4 and 7 consist of 0D clusters with binuclear or tetranuclear units; complex 2 presents a 2D network accompanied by HL− and chloride bridges; complexes 5 and 6 show 1D chains with [Cu3] and [Zn2] subunits. In addition, the electrospray ionization mass spectrometry properties of selected complexes were investigated, revealing the stabilities and structural states of these complexes in solution. These results indicate that H2L is an excellent multiconnection linker for the construction of diverse coordination complexes.