Effect of crystallization conditions and position of fluorine substituents on the composition and structure of {CdTb} tetrafluorobenzoate complexes
摘要
The reaction of the 2,3,4,5-tetrafluorobenzoate (6H-tfb) compounds [Cd(H2O)4-(6H-tfb)]n • n(6H-tfb) (1) and [Tb(H2O)2(6H-tfb)3]n (2) with 1,10-phenanthroline (phen) affords the heterometallic complex [Cd2Tb2(phen)2(6H-tfb)10] (3). The 2,3,5,6-tetra-fluorobenzoate (4H-tfb) complexes [Cd2Tb2(phen)4(4H-tfb)10]·4MeCN (4) and [Cd2Tb2(phen)2(4H-tfb)10] • 4 C6H6 (5) were obtained by reacting cadmium and terbium nitrates with K(4H-tfb) and phen. Depending on the crystallization medium, compounds of different compositions and structures are formed. The use of two isomers of tetrafluorobenzoic acid allowed the analysis of the effect of the substituent position on the structure and the crystal packing of the resulting complexes. Unlike {CdLn} pentafluorobenzoate compounds, new complexes 3–5 do not have a polymer structure, which may be evidence of weaker intermolecular interactions of these isomeric tetrafluorobenzoate anions compared to compounds containing pentafluorobenzoate anions. The synthesized compounds were characterized by X-ray diffraction, IR spectroscopy, and elemental analysis. Noncovalent interactions were investigated using the Hirshfeld surface analysis. The main contribution to the stabilization of the crystal packing is made by π⋯π, C−H⋯F, and C−F⋯π interactions. For complex 2, the luminescence quantum yield and the excited state lifetime are 45% and 1.95 ms, respectively, which are comparable with the corresponding values for heterometallic phenanthroline-containing pentafluorobenzoate complexes.