Aggregation-induced emission and aggregation-promoted photochromism of bis(diphenylmethylene)dihydroacenes

Solid-state photochromism was found in bis(diphenylmethylene)dihydrotetracene, caused by photocyclization of the embedded cis-stilbene motifs.

Aggregation-induced emission properties of BDPM-DHA and BDPM-DHP 4. UV-vis absorption in solution 5. UV-vis reflectance absorption 6. Differential scanning calorimetry and thermal gravimetric analysis 7. Instruments for in-situ single crystal X-ray analysis 8. Photocyclization of cis-stillbene 9. Density functional theory calculation 10. High resolution mass spectrum 11. 1 H-NMR analysis of photocyclization mechanism 12. Electronic structures summary 13. NMR spectra Electronic Supplementary Material (ESI) for Chemical Science. This journal is © The Royal Society of Chemistry 2015 General: Tetrahydrofuran and toluene were distilled from sodium benzophenone ketyl under nitrogen immediately prior to use. All the chemicals and other regents employed were commercially available and used without any further purification if not specified elsewhere. 1 H-NMR and 13 C-NMR spectra recorded on a Brucker ADVANCE III 400MHz spectrometer in deuterated chloroform using tetramethylsilane (TMS; δ = 0) as internal reference. UV-vis solution spectra were measured on a Milton Roy Spectronic 3000 Array spectrophotometer. UV-vis reflectance spectra were measured on Perkin Elmer UV-vis Lambda 20 spectrometer. Photoluminescence was recorded on a Perkin-Elmer LS 55 spectrofluorometer. The MALDI-TOF mass spectrum was recorded on a GCT premier CAB048 mass spectrometer. Differential Scanning Calorimetry (DSC) was performed on Perkin Elmer Differential Scanning Calorimeter Pyris 1.

5, 12-bis(dibromomethylene)-5,12-dihydrotetracene
A mixture of CBr 4 (8.6 g, 25.9 mmol) and PPh 3 (13.6 g, 51.8 mmol) in 100 ml dry toluene was stirred for 30 minutes at room temperature before 5,12-tetracenequinone (2.06 g, 8.0 mmol) was added in one portion and the solution was heated to reflux for 24 h. The reaction mixture was cooled to room temperature; the solid was removed by filtration and washed with toluene. The filtrates were concentrated under reduced pressure and the crude product was obtained. The crude product was triturated with ethanol and filtered to give pure product (4.3 g) in 95% yield. 1

5, 12-bis(diphenylmethylene)-5,12-dihydrotetracene (BDPM-DHT)
To a solution of 5,12-bis(dibromomethylene)-5,12-dihydrotetracene (2.26 g, 4.0 mmol) and phenyl boronic acid (3.90 g, 32 mmol) in 100 mL toluene was added 5 ml ethanol and 5 ml water. The mixture was stirred at room temperature and bubbled with nitrogen for 30 minutes. Then K 2 CO 3 (5.52 g, 40 mmol) and Pd(PPh 3 ) 4 (0.23 g, 0.20 mmol) were added in one portion and the mixture was heated to reflux for 24 hours. The reaction mixture was cooled to room temperature and filtered through a pad (silicon gel height: 5 cm), washing with dichloromethane until the filtrate was clean. The filtrates were concentrated under reduced pressure and the crude product was obtained. The crude product was then triturated with ethanol and filtered to give product (2.18 g) in 97% yield. Firstly, run fast chromatography using CH 2 Cl 2 :hexane = 1: 4 as eluent; then dissolve in CHCl 3 and put them in the hexane atmosphere, high purity products are obtained as colorless crystals after 2 days. 1

13,18-diphenylbenzo[h]naphtho[1,2,3,4-rst]pentaphene(DPBNP)
A standard photochemical reaction vessel with a double-walled quartz immersion well was used for the photo coupling, and a circulating chiller was used to provide cooling water to the quartz immersion well. N 2 was bubbled through a stirred solution of 5, 12-bis(diphenylmethylene)-5,12-dihydrotetracene (260mg, 0.50 mmol)， iodine (0.64 g, 2.50 mmol), and propylene oxide (20 mL) in 300 ml cyclohexane for 20 minutes before photo-irradiation, and the N 2 flow was maintained throughout irradiation with a 500 W high-pressure mercury vapor lamp placed in the immersion quartz well. The progress of the reaction was monitored by TLC. After completion of the reaction (20 minutes), the solvent was evaporated under reduced pressure. 225 mg 13,18-diphenylbenzo[h]naphtho[1,2,3,4-rst]-pentaphene was obtained as yellow powder in a yield of 81% after column chromatography. 1

5, 12-bis(dithiophenylmethylene)-5,12-dihydrotetracene (BDPM-DHT)
To a solution of 5,12-bis(dibromomethylene)-5,12-dihydrotetracene (1.13 g, 2.0 mmol) and 3-thiophenyl boronic acid (2.05 g, 16 mmol) in 50 mL toluene was added 5 ml ethanol and 5 ml water. The mixture was stirred at room temperature and bubbled with nitrogen for 30 minutes. Then K 2 CO 3 (2.76 g, 20 mmol) and Pd(PPh 3 ) 4 (0.12 g, 0.1 mmol) were added in one portion and the mixture was heated to reflux for 24 hours. The reaction mixture was cooled to room temperature and filtered through a pad (silicon gel height: 5 cm), washing with dichloromethane until the filtrate was clean. The filtrates were concentrated under reduced pressure and the crude product was obtained. The crude product was then triturated with ethanol and filtered to give product (0.95 g) in 82% yield. Firstly, run fast chromatography using CH 2 Cl 2 :hexane = 1: 4 as eluent; then dissolve in CHCl 3 and put them in the hexane atmosphere, high purity products are obtained as colorless crystals. 1

Instruments for in-situ single crystal X-ray analysis
Fig. S10 Instrument for collecting X-ray crystallography data with continuous UV irradiation.

UV light source
Scheme S2. Photocyclization of cis-stillbene and its oxidation to phenanthrene. 9. Density functional theory calculation The systems were studied by the DFT calculations performed with the Gaussian 09 program. 1 The geometries were first optimized with B3LYP hybrid density function with the 6-31G (d,p) basis set. The single-point energy and the energy levels of HOMO and LUMO were calculated with the 6-311++G (d,p) basis set.