Anion-tuned self-assembly of zinc(II)–fluconazole complexes: Crystal structures, luminescent and thermal properties

Four novel fluconazole-bridged Zn(II) complexes, [Zn(HFlu)Cl2(DMF)]2 (1), {[Zn(HFlu)2(H2O)2](NO3)2·2DMF}n (2), {[Zn(HFlu)2(H2O)2](NO3)2}n (3) and {[Zn(HFlu)(SCN)2]·H2O}n (4) [HFlu = 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol], have been synthesized and structurally characterized by X-ray diffraction method. The structure of dimeric complex 1 consists of 20-membered macrometallacyclic ring-like structure, in which the Zn(II) ion is in a five-coordinated distorted trigonal bipyramidal geometry with the Zn⋯Zn distance of 10.265(3) Å across the cis HFlu ligand. Complex 2 shows infinite 1-D macrocyclic double chain structure with the central Zn(II) ions being six-coordinated by four HFlu ligands and two apical water molecules and with the intrachain Zn⋯Zn distance of 10.722(3) Å across the trans HFlu ligand. The crystal structure of complex 3 is analogous to that of complex 2 with the intrachain Zn⋯Zn distance of 10.654(2) Å. The structure of complex 4 consists of infinite 1-D coordination polymeric chain with the tetrahedral coordination geometry of Zn(II) ion and with the intrachain Zn⋯Zn distance of 11.173(2) Å across the cis HFlu ligand. Complexes 1–4 show the similar fluorescence emission to the free HFlu ligand at ambient temperature and the thermal stabilities of the complexes have also been investigated.