Synthesis, crystal structures and blue emission of zinc(II) halide complexes of 1-alkyl-imidazole and (–)-nicotine

Abstract

Zn(II) halide complexes of the form L2ZnX2 (X=Cl, Br, I) containing bio-relevant or bio-related ligands like 1-alkyl-imidazoles (alkyl=methyl, ethyl and iso-propyl) or (–)-nicotine are presented. All complexes were characterized by 1H NMR spectroscopy, mass spectrometry and elemental analysis. The molecular structures of the majority of complexes were determined by single crystal X-ray diffraction. The zinc ion exists in a tetrahedral environment coordinated by two halide anions and two nitrogen atoms of the N-heterocycles. Upon photoexcitation the nicotine complexes feature a blue emission which we tentatively assign to phosphorescence.

Zn(II) halide coordination compounds with imidazole and 2-methylimidazole. Structural and computational characterization of intermolecular interactions and disorder

“…The Zn–N distances are similar in all three compounds, whereas those of Zn–X increase with the size of the ligand. They are consistent with those in the related compounds [ 22 , 23 , 24 , 25 ] and fall within the range of bond lengths in complexes of tetrahedrally coordinated Zn with two N-coordinated ligands and two halide atoms, found in the CSD [ 32 ]. There are 932 entries of such complexes having the Zn–N bond with a mean value of 2.09(8) Å (range 1.90–2.50 Å), 670 entries with the Zn–Cl bond (mean value 2.23(3) Å; range 2.13–2.44 Å), 165 entries with compounds having the Zn–Br bond (mean value 2.36(3) Å; range 2.28–2.48 Å) and 97 entries with the Zn–I bond (mean value 2.56(3) Å; range 2.50–2.71 Å).…”

“…Only a limited number of other methyl-substituted zinc(II) imidazole coordination compounds with halide ligands have been structurally characterized, such as dichlorobis(1-methylimidazole)zinc(II) [ 24 ], dibromobis(1-methylimidazole)zinc(II) and diiodobis(1-methylimidazole)zinc(II) [ 25 ]. However, these complexes are N -alkylated and therefore do not have N–H hydrogen bond donors as in our structures.…”

Novel Fluorescent Tetrahedral Zinc (II) Complexes Derived from 4-Phenyl-1-octyl-1H-imidazole Fused with Aryl-9H-Carbazole and Triarylamine Donor Units: Synthesis, Crystal Structures, and Photophysical Properties

“…Furthermore, the N-C-N bond angles for the two imidazole moieties of the complex were at 116.6(3) • for N(1)-C(1)-N(2) and 111.6(2) • for N(4)-C(36)-N(5), while the C-N-C bond angles of the same systems ranged from 1056(3) • to 126.5(3) • . The N-Zn-N and Cl-Zn-Cl bond lengths fall within the range of bond lengths in complexes of tetrahedral coordinated Zn with two N-coordinated ligands and two halide atoms previously reported [39][40][41][42]. The optical properties of the free ligands and their corresponding complexes were studied by UV-Vis absorption in ethanol solution recorded at room temperature (at a concentration of 2 × 10 −4 mol/dm 3 ) and PL emission spectroscopy in both solid and ethanol solutions.…”

Copper(II) complexes bearing cyclobutanecarboxylate and pyridine ligands: a new series of dinuclear paddle-wheel complexes

“…For 1 and 2, π-π* transitions of the pyridine moieties are found at ~ 255 nm (Figs. 1, S6) [16,17]. For 3 and 4, these absorptions are shifted to 261-271 nm with additional short wavelength bands at 212-217 nm (Figs.…”