AIEE-active dichlorobenzene and chlorobenzene ratiometric fluorescent probe based on [2.2]paracyclophane.

Two AIEE-active [2.2]paracyclophanyl-based diester and monoester (1a and 1b) were facilely synthesized by one-pot method and applied as ratiometric fluorescent probe to detect dichlorobenzene (DCB) and chlorobenzene (CB). Compared with compound 1b, 1a exhibits high sensitivity and low detection limits for DCB and CB in dichloromethane (DCM), particularly, the detection sensitivities for ortho-dichlorobenzene (o-DCB), meta-dichlorobenzene (m-DCB) and chlorobenzene can be modulated by AIEE behavior with lower detection limits of 23.64, 56.27, and 5.92 ppm, respectively in THF/H2O mixed solutions with water fraction (fw) of 70 % due to the formation of aggregation-state. The X-ray structure analysis, theoretical calculations and photophysical properties in different solvents were investigated to reveal the distinctive photophysical behaviors of 1a and 1b. The facile synthesis, X-ray structure, AIEE modulated sensing properties for o-DCB, m-DCB, and CB in DCM and THF/H2O mixed solutions make 1a potential application as fluorescent probe for trace DCB and CB detection in drinking water.

Recent Progress in Research on [2.2]Paracyclophane-Based Dyes.

In recent years, the [2.2]paracyclophane (PCP) ring has attracted extensive attention due to its features of providing not only chirality and electron-donating ability but also steric hindrance, which reduces intermolecular π-π stacking interactions and thereby improves the fluorescence properties of dyes. To date, some circularly polarized luminescence (CPL)-active small organic molecules based on the PCP skeleton have been reviewed; however, the application of the PCP ring in improving the photophysical properties of fluorescent dyes is still limited, and new molecular design strategies are still required. This review summarizes and promotes the application of PCP in fluorescent dye design, fluorescence detection, and CPL modulation. We expect that this review will provide readers with a comprehensive understanding of the PCP skeleton and lead to further improvement in fluorescent dye design.

AIE-active aurones for circularly polarized luminescence and trace water detection.

AIE-active phenyl- and [2.2]paracyclophanyl-based aurones (2-Ph and 2-PCP) were synthesized and investigated with different structures and photophysical properties. The results illustrated that the PCP ring can provide chirality, electron-donating ability and steric hindrance. Accordingly, (Rp)/(Sp)-2-PCP exhibit high sensitivity in trace water detection and aggregation-induced CPL with enhanced quantum yields and luminescence dissymmetry factors.

Planar chiral [2.2]paracyclophanyl-based boron fluoride complexes: synthesis, crystal structure and photophysical properties.

Planar chiral [2.2]paracyclophanyl-based boron fluoride complexes (3a-3d) were designed and facilely synthesized. The X-ray structure study, theoretical calculations and CD spectra reveal the intense emission and planar chiral structures of these complexes. In particular, 3a-3d show moderate quantum yields and large Stokes shifts both in solution and solid state. Furthermore, the blue-shifted mechanochromic properties of 3a and 3b were both investigated in the solid state. This work is the first study on planar chiral boron monofluoride complexes within the boron fluoride complex field.

Axially chiral 1,4-dihydropyridine derivatives: aggregation-induced emission in exciplexes and application as viscosity probes.

By combining the fluorophores of axially chiral 1,1'-binaphthol (BINOL) and 1,4-dihydropyridine derivatives, axially chiral 1,4-dihydropyridine derivatives ((R)-/(S)-2) with aggregation-induced emission (AIE) in exciplexes were designed and synthesized. (R)-/(S)-2 emitted low fluorescence in THF solutions of their locally excited states; however, they emitted red-shifted fluorescence in the aggregate state upon exciplex formation. Moreover, (R)-/(S)-2 showed linear and multi-exponential relationships between their local excited and exciplex fluorescence intensities and the viscosity of the medium, which allowed us to determine the viscosities of different mixed solvents. In addition, as an axially chiral viscosity probe, (R)-/(S)-2 show excellent CD signals and have potential applications in the fields of chiral recognition and fluorescence imaging, which will broaden the new family of AIE fluorophores. To the best of our knowledge, there are few reports of axially chiral intramolecular exciplex-mediated AIE molecules.

Solvatochromism, acidochromism and aggregation-induced emission of propeller-shaped spiroborates.

Propeller-shaped pyridyl-enolato-catecholate/-salicyl spiroborates (Sborepy1-6) were synthesized. The complexes Sborepy3-6 show weak emission in fluid solution and aggregation-induced emission enhancement in the aggregation state with large Stokes shifts of 4025-5237 cm-1. Moreover, intense solid-state emissions with high Φf ranging from 25% to 37% were observed for Sborepy3-6 owing to the weak intermolecular interactions in their solid-state. The AIE and intense solid-state emission have been revealed via the X-ray diffraction analysis and theoretical calculations. Furthermore, the solvatochromism in the solution state and the potential application as a fluorescent acidic vapour sensor in the solid state of Sborepy3 and Sborepy6 were also demonstrated.

AIE-active boron complexes based on benzothiazole-hydrazone chelates.

A new family of aggregation-induced emission (AIE)-active monoboron and bisboron complexes based on benzothiazole-hydrazone chelates was synthesized. These complexes showed very weak fluorescence in fluid solution due to active intramolecular rotation and were emissive in high-viscosity solvents or in the aggregation state. Single crystal X-ray diffraction analyses and theoretical calculations were carried out to explain AIE behavior. The large Stokes shifts (3590-7400 cm-1) and relatively highly efficient solid-state emission make these complexes valuable AIE luminophores for further potential applications.

Diaqua-(2,6-dioxo-1,2,3,6-tetra-hydro-pyrimidin-3-ide-4-carboxyl-ato-κN,O)(1,10-phenanthroline-κN,N')manganese(II).

The title compound, [Mn(C(5)H(2)N(2)O(4))(C(12)H(8)N(2))(H(2)O)(2)], was synthesized by the reaction of manganese(II) acetate and orotic acid in the presence of 1,10-phenanthroline. The crystal structure exhibits inter-molecular N-H⋯O and O-H⋯O hydrogen bonds . The Mn coordination environment consists of an N(3)O(3) donor set in an octa-hedral geometry.

4-Amino-13-(1-naphth-yl)-[2,2]paracyclo-phane.

THE TITLE COMPOUND [SYSTEMATIC NAME: 1(2)-amino-4(2)-(1-naphth-yl)-1,4(1,4)-dibenzenacyclo-hexa-phane], C(26)H(23)N, was synthesized from 4-amino-13-bromo-[2,2]paracyclo-phane and 1-naphthalene-boronic acid in the presence of 1,4-dioxane. It is a new cyclo-phane-derived compound which can be regarded as a prospective ligand for asymmetric synthesis and catalysis. The benzene rings of the paracyclo-phane units are very slightly deformed from planarity as shallow boats.