Copper(II) and copper(I) tetrafluoroborate complexes with 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L): Synthesis, structures and luminescence

Copper(II) and copper(I) complexes, [CuIIL2(BF4)2]·0.5H2O, [CuIL2](BF4)·2MeCN and [CuIL2](BF4)·H2O, with 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L) have been synthesized. The compound [CuIIL2(BF4)2]·0.5H2O was obtained in the M:L = 1:1 and 1:2 molar ratios in EtOH solutions. It represents an example of a complex containing coordinated BF4− anion. The Cu–F(BF3) distances, 1.964(2) and 2.000(2) Å, are the shortest for copper tetrafluoroborate complexes. The compounds [CuIL2](BF4)·2MeCN and [CuIL2](BF4)·H2O were obtained in the M:L = 1:1 and 1:2 molar ratios in MeCN solutions. According to X-ray data, the molecules of L in the structures of [CuIIL2(BF4)2]·0.5H2O and [CuIL2](BF4)·2MeCN are coordinated to the copper atoms through N2(pyrazole) and N3(pyrimidine) atoms. The complex [CuIL2](BF4)·2MeCN is unstable in the ambient air and transforms into [CuIL2(BF4)]·H2O. The complex [CuIL2](BF4)·H2O was found to display orange photoluminescence.

Graphical abstractCopper(II) and copper(I) tetrafluoroborate complexes with 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L), [CuIIL2(BF4)2]·0.5H2O, [CuIL2](BF4)·2MeCN and [CuIL2](BF4)·H2O, have been synthesized. The compound [CuIIL2(BF4)2]·0.5H2O represents an example of a complex containing coordinated BF4− anion. The Cu–F(BF3) distances, 1.964(2) and 2.000(2) Å, are the shortest for copper tetrafluoroborate complexes. The complex [CuIL2](BF4)·H2O was found to display orange luminescence.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Copper(II) and copper(I) complexes with a 4-pyrazolylpyrimidine ligand. ► Orange luminescence of copper(I) complex. ► Coordination of BF4− to copper(II). ► The shortest Cu–F(BF3) distances (1.964 and 2.000 Å).