Multicolor Luminescent Supramolecular Bidirectional Shuttles Driven by Light

Abstract

Possessing special photophysical behavior, supramolecular space-confined assembly is widely applied in bioimaging, information anti-counterfeiting, and luminescent materials. Herein, two different multicolor luminescent supramolecular bidirectional shuttles driven by light are reported, which are constructed by spiropyran-modified p-styrene derivatives (BPSP), cucurbit[7]uril (CB[7]) and cucurbit[8]uril (CB[8]). CB[7] encapsulated BPSP not only effectively enhance the fluorescence intensity both in the ring-closed and ring-open states accompanied with multicolor luminescence from blue to red, but also produce ortho-hexagonal nanosheets. Different from CB[7], the binding of CB[8] to BPSP formed a nanospherical topological morphology. It induce the red-shift of fluorescence from blue to yellow, which completely transform into red fluorescence in the dark. Both the multicolor luminescence and topological morphology can be reversibly regulate under alternating visible light and darkness. Due to the photo-controlled time-dependent multicolor reversible luminescence of the two kinds of supramolecular assemblies, they are successfully applied to logic gates, bidirectional reversible anti-counterfeiting, and controllable cell imaging, providing a new strategy for macrocycle-confined molecular assembly.

Keywords: cucurbituril; multicolor luminescent; photo‐responsive; supramolecular assembly.

Scheme 1

Schematic illustration for constructing photo‐controlled time‐dependent multicolor luminescent supramolecular shuttle with tunable topological morphology.

Figure 1

a) UV‐vis absorption spectra of BPMC with the addition of CB[7] ([BPMC] = 2.0 × 10⁻⁵ M, [CB[7]] = 0–4.4×10⁻⁵ M). b) ¹H NMR spectra of BPMC with the addition of CB[7] (D₂O:DMSO‐d₆ = 20:1, [BPMC] = 5.0×10⁻⁴ M, [CB[7]] = 0, 3 × 10⁻⁴, 6 × 10⁻³ M). c) UV‐vis absorption spectra of BPMC with the addition of CB[8] ([BPMC] = 2.0 × 10⁻⁵ M, [CB[8]] = 0–3.6 × 10⁻⁵ M). d) DLS of BPMC⊂CB[7] ([BPMC] = 2.0 × 10⁻⁵ M, [CB[7]] = 2.0 × 10⁻⁵ M). TEM images of e) BPMC⊂CB[7] and f) BPMC⊂CB[8] ([BPMC] = [CB[7]] = [CB[8]] = 2.0×10⁻⁵ M).

Figure 2

a) Fluorescence spectra of BPSP with the addition of CB[7] ([BPSP] = 2.0 × 10⁻⁵ M, [CB[7]] = 0–2.4 × 10⁻⁵ M). (b) Fluorescence spectra of BPMC with the addition of CB[7] ([BPMC] = 2.0×10⁻⁵ M, [CB[7]] = 0–3.0 × 10⁻⁵ M). c) Fluorescence spectra of BPMC⊂CB[7] upon visible light irradiation ([BPMC] = 2.0 × 10⁻⁵ M, [CB[7]] = 2.0 × 10⁻⁵ M). d) Time‐dependent fluorescence spectra of BPSP⊂CB[7] in the dark. Inset: fluorescence image of BPSP⊂CB[7] under UV portable light ([BPSP] = 2.0×10⁻⁵ M, [CB[7]] = 2.0×10⁻⁵ M). e) The CIE 1931 chromaticity diagram of BPSP⊂CB[7] in the dark. f) Fluorescence intensity at 480 nm and 616 nm of BPSP⊂CB[7] during cyclic darkness and visible irradiation ([BPSP] = 2.0×10⁻⁵ M, [CB[7]] = 2.0×10⁻⁵ M).

Figure 3

a) Fluorescence spectra of BPSP with the addition of CB[8] ([BPSP] = 2.0×10⁻⁵ M, [CB[8]] = 0–1.2 × 10⁻⁵ M). (b) Fluorescence spectra of BPMC with the addition of CB[8] ([BPMC] = 2.0 × 10⁻⁵ M, [CB[8]] = 0–2.4 × 10⁻⁵ M). c) Ex‐Em mapping spectra of BPMC⊂CB[8] upon visible light irradiation ([BPMC] = 2.0 × 10⁻⁵ M, [CB[8]] = 2.0 × 10⁻⁵ M). d) The CIE 1931 chromaticity diagram of BPSP with the addition of CB[8] and cyclic visible light as well as darkness. e) UV‐vis absorption spectra of BPSP⊂CB[8] upon visible light. f) Time‐dependent fluorescence spectra of BPSP⊂CB[8] in the dark. Inset: fluorescence image of BPSP⊂CB[8] under UV portable light. g) Fluorescence intensity at 616 nm of BPSP⊂CB[8] during cyclic darkness and visible irradiation ([BPSP] = 2.0 × 10⁻⁵ M, [CB[8]] = 2.0 × 10⁻⁵ M). h) Fluorescence spectra of BPMC, BPMC⊂CB, [7] and BPMC⊂CB[8] ([BPSP] = 2.0 × 10⁻⁵ M, [CB[7]] = [CB[8]] = 2.0 × 10⁻⁵ M). i) Normalized fluorescence spectra of BPSP⊂CB, [7] BPSP⊂CB[8] and absorption spectra of BPSP, BPMC ([BPSP] = [BPMC] = 2.0 × 10⁻⁵ M, [CB[7]] = [CB[8]] = 2.0 × 10⁻⁵ M).

Figure 4

Schematic diagram and corresponding results for constructing the logic gate containing a) “NOT” gate and b) “NOR” gate. c) The process of dynamic information encryption and light‐driven decryption using BPMC⊂CB[8] and BPMC⊂CB.[7]. d) Confocal laser scanning microscopy images of photo‐modulation after co‐incubation of assemblies and A549 cells ([BPSP] = 2.0 × 10⁻⁵ M, [CB[8]] = 2.0 × 10⁻⁵ M, [CB[7]] = 2.0 × 10⁻⁵ M).