Multilayer 3D Chiral Folding Polymers and Their Asymmetric Catalytic Assembly

A novel class of polymers and oligomers of chiral folding chirality has been designed and synthesized, showing structurally compacted triple-column/multiple-layer frameworks. Both uniformed and differentiated aromatic chromophoric units were successfully constructed between naphthyl piers of this framework. Screening monomers, catalysts, and catalytic systems led to the success of asymmetric catalytic Suzuki-Miyaura polycouplings. Enantio- and diastereochemistry were unambiguously determined by X-ray structural analysis and concurrently by comparison with a similar asymmetric induction by the same catalyst in the asymmetric synthesis of a chiral three-layered product. The resulting chiral polymers exhibit intense fluorescence activity in a solid form and solution under specific wavelength irradiation.


General Information
Unless otherwise stated, all reactions were magnetically stirred and conducted in oven-dried glassware in anhydrous solvents under Ar. Heated oil baths were used for reactions requiring elevated temperatures. Solvents were removed under reduced pressure at 40-65 °C using a rotavapor. All given yields are isolated yields of chromatographically and NMR spectroscopically materials.
The 1 H and 13 C NMR spectra were recorded in CDCl3 on 400 MHz and 100 MHz instruments with TMS as internal standard. For referencing of the 1 H NMR spectra, the residual solvent signal (δ = 7.26 for CDCl3) was used. In the case of the 13 C NMR spectra, the signal of solvents (δ = 77.06 ± 0.03 for CDCl3 and δ = 39.52 for DMSO-d6) were reported in ppm with respect to TMS. Data are represented as follows: chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, m = multiplet), coupling constant (J, Hz), and integration. MALDI-TOF analyses were carried out using an ABI/MDS SCIEX 4800 Mass Spectrometer with HABA matrix. UV-Vis spectra were collected on an Agilent 8453 UV-Visible Spectroscopy system. Fluorescence data were collected by using cary Eclipse Fluorescence Spectrophotometer and Eclipse ADL program. GPC data were collected by using TOSOH EcoSEC HLC-8320 GPC equipped with a dual-flow refractive index detector. A UV detector is also included for UV visible polymers and can be used in tandem with the RI detector. The installed columns have a range of 500-10 7 Da. Samples were run for 30 minutes with flow rate 1.001 mL/min. Polystyrene (PS) standards were used for calibration in our experiments.
X-ray data were collected on a Rigaku XtaLAB Synergy-i Kappa diffractometer equipped with a PhotonJet-i X-ray source operated at 50 W (50kV, 1 mA) to generate Cu Kα radiation (λ = 1.54178 Å) and a HyPix-6000HE HPC detector. Crystals were transferred from the vial and placed on a glass slide in polyisobutylene. A Zeiss Stemi 305 microscope was used to identify a suitable specimen for X-ray diffraction from a representative sample of the material. The crystal and a small amount of the oil were collected on a MiTeGen 100 micron cryoloop and transferred to the instrument where it was placed under a cold nitrogen stream (Oxford 700 series) at 100K.The sample was optically centered with the aid of a video camera to ensure that no translations were observed as the crystal was rotated through all positions. A unit cell collection was then carried out. After it was determined that the unit cell was not present in the CCDC database a data collection strategy was calculated by CrysAlis Pro1 . The crystal was measured for size, morphology, and color.
The chiral polymer samples were coated with a thin gold layer by sputtering, and a NANOSCIENCE Phenom ProX scanning electron microscopy (SEM) (Phoenix, AZ, USA) was used to observe the morphological characteristics.
The CD measurements were carried out using a Jasco J-815 spectrometer equipped with a Peltier MPTC-490S temperature-controlled cell holder unit. A 200-μL chiral polymer sample at a concentration of 0.2 mg/mL in HPLC gradient methanol was placed in a 1 mm quartz cuvette on the temperature-controlled cell holder. CD spectra were collected using Jasco Spectra measurement version 2 software for a wavelength range of 190-400 nm with a data pitch of 0.1 nm using a bandwidth of 1 nm and scanning speed of 100 nm/min. Each spectrum was corrected by subtraction with corresponding methanol background.
An ethanol solution of the former crude product and SeO2 (222 mg, 2.0 mmol) were placed in a 50 mL round bottle flask under Ar condition. The mixture was stirred at 80 o C for 8 hours. After completion of the reaction, the mixture was extracted with DCM. The residue was dried by rotavapor and purified by column chromatography using Hexane/EtOAc (8/1) as an eluent to get pure product as yellow solid 2 (0.32 g, 47%). 125.02, 83.16, 25.17, 24.21

Typical polymerization procedure for Polymer 1A-1C and 2A-2C
Take Polymer 1A as an example for synthesis.
To an oven dried 50 mL round bottle flask under argon, 1 (128.0 mg, 0.2 mmol, 1 equiv), 3 (58.0 mg, 0.2 mmol, 1 equiv), Pd(S-BINAP)Cl2 (8.0 mg, 0.01mmol, 0.05 eq) and K2CO3 (110.0 mg, 0.8 mmol, 4 equiv) were dissolved into 9.5 mL THF and 1.5 mL H2O, equipped with an air condenser. The bottle flask was degassed under vacuum and backfilled with argon 6 times. It was then heated at 85 o C for 6 days. After reaction completed, the mixture was cooled to room temperature and slowly poured reaction solution into MeOH/6N HCl (25 mL/5 mL). The precipitated solution was stirred for 0.5 h at room temperature, then recovered by filtration through a Buchner funnel. The solid was separately washed with 2N HCl (10 mL) and H2O (10 mL

Refinement Details
After data collection, the unit cell was re-determined using a subset of the full data collection. Intensity data were corrected for Lorentz, polarization, and background effects using the CrysAlis Pro1 . A numerical absorption correction was applied based on a Gaussian integration over a multifaceted crystal and followed by a semi-empirical correction for adsorption applied using the program SCALE3 ABSPACK 2 . The SHELX-2014 3 , series of programs was used for the solution and refinement of the crystal structure within OLEX2 software 4 . Within the structure a water molecule (O2) was partially occupied (0.17) and phenyl ring (C23 < C28) nearest to that site was positionally disorder in relation to the presence of the water molecule (A sites when the water molecule is present and B sites when the water molecule is absent). To help maintain reasonable ADP values and bond lengths, RIGU, SIMU and AFIX 66 restraints and constraints were applied to the disordered sites. Hydrogen atoms bound to carbon and nitrogen atoms were geometrically constrained using the appropriate AFIX commands.