High efficiency luminescent liquid crystal : aggregation-induced emission strategy and biaxially oriented mesomorphic structure

Department of Chemistry, The Hong Kong University of Science & Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China, School of Chemistry and Chemical engineering, Shanghai Jiao Tong University, Shanghai 200240, China, School of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060, China, State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130023, China, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and State Key Laboratory of Molecular Neuroscience, HKUST

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry This journal is © The Royal Society of Chemistry 2012 S3 1 H and 13 C NMR spectra were measured on a Bruker ARX 400 spectrometer using chloroform-d as solvent and tetramethylsilane (TMS, δ = 0) as internal standard.Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) high-resolution mass spectra (HRMS) were recorded on a GCT premier CAB048 mass spectrometer.Elemental analysis was performed on an Elementar Vario EL equipment (Germany).Absorption spectra were taken on a Milton Roy Spectronic 3000 Array spectrometer.Emission spectra were taken on a Perkin-Elmer spectrofluorometer LS 55.The quantum yields (Φ F 's) in THF solutions were estimated using 9,10-diphenylanthracene (Φ F = 90% in cyclohexane) as standard according to the following equation: where Ф (Ф st ), A (A st ), F (F st ), and n (n st ) are the fluorescence quantum efficiency, the absorbance at the excitation wavelength, the integral over the emission spectrum, and the refractive index of the solvent used for the testing sample (standard), respectively.Different to the comparison technique utilized for the solution quantum efficiency measurement, absolute measurement was adopted for the film photoluminescence quantum efficiency (Φ F,f ) using an integrating sphere [1] with an error of ±5%.
The thermal stability of the resulting compound TPE4Mes was evaluated on a Perkin-Elmer TGA 7 under nitrogen at a heating rate of 20 °C/min.A Perkin-Elmer DSC 7 was employed to measure the phase transition thermograms.An Olympus BX 60 polarized optical microscope (POM) equipped with a Linkam TMS 92 hot stage was used to observe the anisotropic optical textures.One-dimensional wide-angle X-ray diffraction (1D-WAXD) powder experiments were performed on a Philips X'Pert Pro diffractometer with a 3 kW ceramic tube as the X-ray source (Cu Kα) and an X'celerator detector.The sample stage was set horizontally and the samples were protected by nitrogen gas during the measurements.The reflection peak positions were calibrated with silicon powder (2θ > 15°) and silver behenate (2θ < 10°).Background scattering was recorded and subtracted from the sample patterns.A temperature control unit (Paar Physica TCU 100) in conjunction with the diffractometer was utilized to study the

S4
structure evolutions as a function of temperature.Two dimensional (2D) WAXD patterns were obtained using a Bruker D8 Discover diffractometer with general area detector diffraction system (GADDS) as a 2D detector.2D WAXD experiments were carried out using molecularly oriented sample to identify the mesophase.To obtain the mono-domains oriented liquid crystalline film, TPE4Mes was slowly cooled from its isotropic state to 140 °C, annealed overnight [2] and then quenched to room temperature.The organic phase was washed with 150 mL of water three times and 100 mL of brine twice and then dried over 5 g of magnesium sulfate for 4 h.The crude product was condensed and purified on a silicagel column using hexane as eluent.A white solid of 6 was obtained in 60.6% yield.

Preparation of 1-ethynyl-4-(4-pentylcyclohexyl)benzene (10).
Into a 100 mL round-bottom flask was placed 30 mL of a THF solution of 9 (3.27 g, 10 mmol) and 15 mL of 1 M TBAF.After stirring for 45 min, 30 mL of water was added.The mixture was extracted with 200 mL of DCM three times and then washed by brine twice.The mixture was then dried over 5 g of anhydrous sodium sulfate for 4 h.The crude product was condensed and purified on a silica-gel column using hexane as eluent.A white solid of 10 was obtained in 97.8% yield.Preparation of TPE4Mes.Into a 100 mL two-necked round-bottom flask equipped with a reflux condenser was placed 0.26 g of zinc dust (4 mmol), 619.9 mg (0.5 mmol) of 1.The flask was evacuated under vacuum and flushed with dry nitrogen three times, after which 60 mL of THF was added.The mixture was cooled to around 0 °C, to which 0.22 mL (2 mmol) of titanium tetrachloride was slowly added.The mixture was slowly warmed to room temperature and then stirred for 24 h under reflux.After being cooled to room temperature again, the reaction mixture was quenched with a 10% potassium carbonate aqueous solution.A large amount of water was added until the solid is turned to grey or white.
The mixture was then extracted with DCM three times and the combined organic layer was washed by brine twice.The mixture was dried over 5 g of anhydrous sodium sulfate.The crude product was condensed and purified on a silica-gel column using a mixture of DCM/hexane (1:3 v/v) as eluent.A white solid was obtained in 65.1% yield.
Scheme S1.Synthetic route to intermediate 3

Fig. S2 (
Fig. S2 (A) Emission spectra of 3 in THF and THF/water mixtures; (B) Plots of the mission maxima of

Fig. S4
Fig. S4 TGA thermogram of 1 measured under nitrogen at a heating rate of 20 o C/min.

Fig. S5
Fig. S5 Peak fitting of the XRD pattern for TPE4Mes recorded at 100 o C during the cooling process.

Fig. S6
Fig. S6Schematic illustration of the geometry adopted in 2D WAXD experiments with the X-ray inci-

Scheme S1. Synthetic route to intermediate 3
Scheme S1.Synthetic route to intermediate 3 Fig. S1 Absorption spectra of TPE4Mes and compound 3 in THF.ε: molar absorptivity; concentration Fig. S2 (A) Emission spectra of 3 in THF and THF/water mixtures; (B) Plots of the mission maxima of 3 in THF and THF/water mixtures versus water fractions (f w ).Concentration = 20 μM.Excitation wave- Fig. S5 Peak fitting of the XRD pattern for TPE4Mes recorded at 100 o C during the cooling process.

Table S1 .
1D WAXD analysis data of TPE4Mes at varying temperatures a d-spacing (in units of nm).b isotropic state.c mesomorphic state.