Luminescent Zinc(II) Complexes of Fluorinated Benzothiazol-2-yl Substituted Phenoxide and Enolate Ligands

Abstract

Zn(II) complexes of the following new, fluorine-containing, benzothiazole-derived ligands have been synthesized and characterized crystallographically: 2-(3,3,3-trifluoro-2-oxopropyl)benzothiazole (3), 4,5,6,7-tetrafluoro-2-(3,3,3-trifluoro-2-oxopropyl)benzothiazole (4), 4,5,6,7-tetrafluoro-2-(2-hydroxyphenyl)benzothiazole (12), 2-(3,4,5,6-tetrafluoro-2-hydroxyphenyl)-4,5,6,7-tetrafluorobenzothiazole (13), and 2-(3,4,5,6-tetrafluoro-2-hydroxyphenyl)benzothiazole (16); the Cu(II) complex of ligand 4 is also reported. These are analogs of the important photo- and electroluminescent material [Zn(BTZ)(2)](2), where H-BTZ = 2-(2-hydroxyphenyl)benzothiazole. DFT calculations indicate that HOMO and LUMO energy levels in these materials are substantially lowered by fluorination. The fluorinated ZnL(2) complexes are mononuclear (in contrast to the dinuclear, nonfluorinated material [Zn(BTZ)(2)](2)). They easily sublime and show broad visible photoluminescence. A common crystallographic feature is the existence of pairs of fluorinated ZnL(2) molecules related by inversion centers, with their π systems facing one another.

Chemistry of 3-carbonyl-2-methyl-4-oxo-4H-1-benzopyrans

“…and benzothiazole 157 84,85 by treating the tetrafluorinated ester 118a respectively with o-phenylenediamine 154 and 2-aminothiophenol 155 in boiling ethanol. Later Li et al 86 reported that the product 157, if prepared from 118a and 155, remains admixed with the benzothiazole 158; it can be had exclusively by treating the acid chloride 159 with the thiophenol 155 in N-methyl-2-pyrrolidone at 100 °C. A mixture of Zn(OAc) 2 and potassium salt of thiazole 157 in a molar ratio of 1:2 in MeOH-H 2 O forms the four coordinated Zn(II) complex 160. as well as with phenyltrimethylammonium tribromide 91 give the corresponding 3-bromoacetylchromones (Equation 10), the latter reagent being claimed to improve the yield.…”

Zinc and cadmium halide compounds with the tridentate ligand 2-(methylsulfanyl)-N-(pyridin-2-ylmethylidene)aniline showing yellow luminescence

“…The compounds ZnLCl 2 (1) and CdLC 2 (4) show a relatively intense yellow color emission, while ZnLBr 2 (2+3), CdLBr 2 (5) exhibit a medium intense yellow color emission upon irradiation of 400 nm. The emission spectra of all four compounds contain only one peak with a maximum at around 540 nm (535 nm for the chloride compounds, 545 nm for the bromide compounds), which is assigned to the ligand π-π* transition [29][30][31][32][33][34]. For ZnLCl 2 (1), CdLCl 2 (4) and CdLBr 2 (5); although the excitation spectra contain two peaks, varying the excitation wavelength did not make any influence of the shape and position of emission spectra.…”

Field-induced single-ion magnetic behaviour in a highly luminescent Er3+ complex

“…This complex has shown to exhibit an intrinsic radiative lifetime of 13±1ms. When this compound, [Er(F-TPIP)3], is associated with a perfluorinated zinc-based organic chromophore, the zinc salt of 2-(3,4,5,6-tetrafluoro-2-hydroxyphenyl-4,5,6,7-tetrafluorobenzothiazole, [Zn(F-BTZ)2] [4], in a composite material, it becomes very highly sensitised. In this situation the sensitization is attained in an indirect way: the [Zn(F-BTZ)2] in the medium is able to absorb radiation in the 350 to 475 nm range and transmit the energy to the erbium ion in the [Er(F-TPIP)3].…”