18-Crown-6 Coordinated Metal Halides with Bright Luminescence and Nonlinear Optical Effects

Abstract

The crown-ether coordination compounds ZnX 2 (18-crown-6), EuX 2 (18-crown-6) (X: Cl, Br, I), MnI 2 (18crown-6), Mn 3 Cl 6 (18-crown-6) 2 , Mn 3 I 6 (18-crown-6) 2 , and Mn 2 I 4 (18-crown-6) are obtained by ionic-liquid-based synthesis. Whereas MX 2 (18-crown-6) (M: Zn, Eu) show conventional structural motives, Mn 3 Cl 6 (18-crown-6) 2 , Mn 3 I 6 (18-crown-6) 2 , and Mn 2 I 4 (18-crown-6) exhibit unusual single MnX 4 tetrahedra coordinated to the crown-ether complex. Surprisingly, some compounds show outstanding photoluminescence. Thus, rare Zn 2+ -based luminescence is observed and unexpectedly efficient for ZnI 2 (18-crown-6) with a quantum yield of 54%. Unprecedented quantum yields are also observed for Mn 3 I 6 (18-crown-6) 2 , EuBr 2 (18-crown-6), and EuI 2 (18-crown-6) with values of 98, 72, and 82%, respectively, which can be rationalized based on the specific structural features. Most remarkable, however, is Mn 2 I 4 (18crown-6). Its specific structural features with finite sensitizer−activator couples result in an extremely strong emission with an outstanding quantum yield of 100%. Consistent with its structural features, moreover, anisotropic angle-dependent emission under polarized light and nonlinear optical (NLO) effects occur, including second-harmonic generation (SHG). The title compounds and their optical properties are characterized by single-crystal structure analysis, X-ray powder diffraction, chemical analysis, density functional theory (DFT) calculations, and advanced spectroscopic methods.

Electrochemical and Fluorescent Properties of Crown Ether Functionalized Graphene Quantum Dots for Potassium and Sodium Ions Detection

“…As shown in Figure S3a,b, a slight increase in fluorescence was observed when increasing concentrations of the two ions were added to the GQDs solutions, regardless of the added salt. For the unbound crown ethers, the observed increase in emission (Figure S3c-f) is particularly evident for the complexation of the ion of interest with the corresponding crown ether (K + for NH 2 -18-crown-6 and Na + for NH 2 -15-crown-5), as also reported in the literature for a similar system [44,45].…”

Unveiling White Light Emission of a One-Dimensional Cu(I)-Based Organometallic Halide toward Single-Phase Light-Emitting Diode Applications

“…Figure c depicts the specific coordination for the crown cation. Each 18-crown-6 ether is coordinated to a Cs atom to form the cation, which is comparable with previously reported crown-cation-based compounds. , Figure a further gives the Rietveld difference plot of the XRD pattern of (C 12 H 24 O 6 )­CsCu 2 Br 3 , which is consistent with the simulated data of (C 12 H 24 O 6 )­CsCu 2 Br 3 . One can also find that the crystal powder of (C 12 H 24 O 6 )­CsCu 2 Br 3 shows a white body color and white emission under daylight (left) and 365 nm UV light (right), as given in the inset of Figure a.…”

Insights of the Structure and Luminescence of Mn2+/Sn2+-Containing Crown-Ether Coordination Compounds

“…Surprisingly, the Mn 2+ -based compounds showed very intense emission with extraordinarily high quantum yields (e.g., ≥95% for Mn 3 I 6 (18crown-6) 2 , Mn 2 I 4 (18-crown-6)) as well as nonlinear optical (NLO) effects (i.e., Mn 2 I 4 (18-crown-6)). 23 The promising luminescence performance of some crownether coordination compounds in the Mn 2+ /18-crown-6 system has motivated us to study the structural and optical properties of crown-ether coordinated divalent cations more systematically, especially including the smaller crown ethers 12-crown-4 and 15-crown-5. As a result, we present the syntheses, structures, and optical properties of MnI 2 (15- understanding the unique situation of some compounds in the Mn 2+ /18-crown-6 system.…”