Thiocyanate-induced conformational transformation of a flexible fluconazole ligand in Cd(II) coordination polymers

Six Cd(II) coordination polymers with a flexible fulconazole ligand, {[Cd(HFlu)2(H2O)2](ClO4)2}n (1), {[Cd(HFlu)3(NO3)]2(NO3)2·H2O}n (2), {[Cd(HFlu)2(SCN)](ClO4)}n (3), {[Cd(HFlu)2(SCN)](NO3)}n (4), {[Cd(HFlu)2Cl](SCN)}n (5) and {[Cd(HFlu)2(SCN)2]·2H2O}n (6) [HFlu = 2-(2′,4′-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol] have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 presents a 1-D chain-like structure with anti–gauche (A-G) conformation of HFlu. Complex 2 shows a 1-D ladder-like structure with both A-G and anti–anti (A-A) conformations of HFlu, and complexes 3, 4 and 5 show the 2-D grid structures bridged by A-G and A-A HFlu. However, in the 2-D grid network of 6, only A-A conformation of HFlu is observed. The conformational change of the HFlu ligand is induced step-by-step by the addition of the SCN− inorganic anion. The thermal stability and fluorescence of these complexes have also been studied.