MaterialsAll chemicals and solvents were used without further purification. Pyromellitic dianhydride ( > 98.0%) was purchased from Energy-Chemical. Pyrene ( > 98.0%) was purchased from J&K Scientific. (1 R,2 R)-(-)−1,2-cyclohexanediamine ( > 98.0%, TCI), (1 S,2 S)-( + )−1,2-cyclohexanediamine ( > 98.0%, TCI), N,N-dimethylformamide (DMF, Concord Technology (Tianjin) Co., Ltd). AR, >99.0%), 1-Methyl-2-pyrrolidone (NMP, Inno-chem, GC, >99.5%), deionized water (Milli-Q water, 18.2 MΩ·cm) was prepared in the laboratory. The synthetic procedures of (RRRRRR)-PMDI-Δ (R-Δ) and (SSSSSS)-PMDI-Δ (S-Δ) were listed in Supplementary Fig. 1. The rac-PMDI-Δ was prepared by mixing R-PMDI-Δ and S-PMDI-Δ with equal mass.Co-assembly protocol in DMF/H2OTypically, R/S-PMDI-Δ (2.00 mg, 2.25 μmol, 1 eq) and pyrene (0.68 mg, 3.36 μmol, l.5 eq) were dissolved in 550 μL DMF by ultrasound to form a transparent solution. Then, 450 μL H2O (anti-solvent) was added, resulting in a yellow-green suspension (total volume 1000 μL, DMF/H2O v/v = 55%/45%, [R/S-PMDI-Δ] = 2.25 mM, [Pyrene] = 3.36 mM). The suspension was then annealed at 140 °C for 10 minutes until the charge-transfer (CT) complex between the two molecules was broken and the yellow color of the mixture completely faded. After natural cooling to room temperature, the white suspension was expected to turn yellow-green again. The precipitates were then separated by centrifugation (13000 r/min, 12000×g) and washed twice with deionized water to remove any residual organic solvent. Finally, transfer the precipitates to a clean silicon wafer, glass slide or quartz cuvette for further characterization. The detailed assembly process was shown in Supplementary Figs. 2 and 3.To gain more insights into morphology evolution and assembly mechanism, it is essential to capture the initial structure of assemblies. Hence, it is requisite to promptly transfer the samples after annealing to a silicon wafer and remove any remaining organic solvent. For the preparation of the samples presented in Fig. 2l, which depicted a natural cooling time of 0 and 2 minutes respectively, a precipitation separation method distinct from centrifugation was employed. That is, for the samples that had just been annealed and the samples that had been left at room temperature for 2 minutes after annealing, 50 μL suspensions were pipetted and rapidly dropped onto a silicon wafer. Following that, the upper layer of liquid was removed, and the remaining precipitates on the silicon wafer were washed twice with 50 μL of deionized water. Finally, the samples were left to dry naturally at room temperature and were characterized by SEM after being coated with a thin layer of Pt in the same way as other samples.Co-assembly protocol in NMP/H2OTypically, R/S-PMDI-Δ (2.00 mg, 2.25 μmol, 1 eq) and pyrene (1.14 mg, 5.64 μmol, 2.5 eq) were dissolved in 600 μL NMP by ultrasound to give a transparent solution. Subsequently, 400 μL H2O (anti-solvent) was added and a yellow-green suspension was obtained (total volume 1000 μL, NMP/H2O v/v = 60%/40%, [R/S-PMDI-Δ] = 2.25 mM, [Pyrene]= 5.63 mM). The subsequent processing method of the suspension was the same as the protocol in DMF/H2O.Self-assembly protocolThe self-assembly protocol of PMDI-Δ was the same as the co-assembly protocol above, except that the electron donor pyrene was not added.NMR and mass spectra1H NMR and 13C NMR spectra were recorded on a Bruker Advance spectrometer (1H: 400 MHz, 13C: 100 MHz) in CDCl3 at 298 K. Mass spectra were obtained on Bruker Solarix mass spectrometer (for ESI). The NMR and mass spectra of PMDI-Δ were shown in Supplementary Figs. 42 to 47.Scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM)SEM was performed on S4800 (Hitachi, Japan) with an accelerating voltage of 10 kV and a working current of 10 µA to ex situ characterize the co-assemblies. Before SEM measurements, the samples on silicon wafers were coated with a thin layer of Pt to increase the contrast. AFM images were obtained on a Dimension FastScan (Bruker), using ScanAsyst mode under ambient conditions. Fastscan B probes were used for the scan, and samples were prepared by dropping the aqueous dispersion of the co-assemblies onto a double-sided tape. TEM images were operated on a JEOL-2100F electron microscope operating at accelerating voltages of 200 kV.Fluorescence microscope image (FM)The co-assemblies were observed on an IX 83 (Olympus) fluorescence microscope. The samples were prepared by dropping the aqueous dispersion of the co-assemblies onto the glass slide and naturally dried solvent.Ultraviolet and visible absorption spectroscopy (UV-Vis)UV-Vis spectra were measured on a UV-Vis spectrometer (UV-2600 Shimadzu). Solution samples were loaded in a quartz cuvette with 2 mm optical path for pyrene and 1 cm optical path for PMDI-Δ. Solid samples were uniformly dispersed into BaSO4 powders to record the UV-Vis diffuse-reflectance spectra. The optical bandgaps (Eo) for helicoids were calculated from the maximum edge (λmax) of the absorption spectrum, given by the formula Eo = 1240 / λmax.Fluorescence spectra (FL)The fluorescence spectra were recorded on a F-4600 fluorescence spectrophotometer (Hitachi) at a voltage of 400 V with a 5 nm slit for both the excitation and emission sides. Solution samples were loaded in a quartz cuvette with 2 mm optical path for pyrene and 1 cm optical path for PMDI-Δ. The aqueous dispersion of the solid samples was charged in 1 mm quartz cuvette for FL spectra measurement. Fluorescence decay curves were recorded on a FLS 980 (Edinburgh Instruments). The wavelength of the excitation laser was 358.4 nm. Fluorescence quantum yields were measured on a FluoroMax+ (HORIBA) instrument by using an integrating sphere.Circular dichroism (CD) and linear dichroism (LD) spectrumSolution samples were loaded in a quartz cuvette with 2 mm optical path for pyrene and 1 cm optical path for PMDI-Δ. They were recorded on CD spectrometer J-815 (JASCO) at a scanning rate of 500 nm min−1 in the range of 200 ~ 600 nm. The CD and LD spectra of solid samples were simultaneously recorded for each sample on CD spectrometer J-1500 (JASCO) under a diffuse-reflectance mode at a scanning rate of 500 nm min−1 in the range of 200 ~ 800 nm. CD and LD spectra of each solid sample were recorded more than 3 times to ensure the chiroptical signals. The absorptive dissymmetry factor (gabs, also known as gCD) spectra were directly transferred from CD spectra using the SpectraManager software of JASCO. The gabs can be used to quantify the magnitude of CD, given by the formula gabs = 2 (εL–εR)/(εL + εR), where εL and εR refer to the extinction coefficients for left- and right-handed circularly polarized light, respectively.Circularly polarized luminescence spectrum (CPL)The CPL spectra were recorded on CPL-300 spectrophotometer (JASCO) in a range of 400 ~ 750 nm. The aqueous dispersion of the solid samples was charged in 1 mm quartz cuvette for CPL spectra measurement. The slits for both the excitation and emission sides were 3000 μm. The luminescence dissymmetry factor (glum) spectra were transferred from CPL spectra using the SpectraManager software of JASCO. The glum was used to quantify the extent of chiral fluorescence dissymmetry, given by the formula glum = 2 (IL–IR)/(IL + IR), where IL and IR represent the intensities of left and right circularly polarized light, respectively. CPL spectra of each solid sample were recorded more than 3 times by flipping and rotating the cuvette to ensure the chiroptical signals.Powder X-ray diffraction (XRD) measurementsThe solid samples were loaded directly onto a glass sample holder to record the X-ray diffraction spectra on EmpyreanX (PANalytical B.V.) with Cu/Kα radiation (λ = 1.5406 Å) at 40 kV and 40 mA. The scanning range was from 1° to 40°.Single crystal X-ray diffraction (XRD) measurementsThe single-crystal XRD was measured by XtaLAB Synergy-R (Rigaku). The structures were solved by direction methods and refined by a full matrix least squares technique based on F2 using SHELXL 97 program (Sheldrick, 1997).
R-PMDI-Δ single crystalDMF
In a 2 mL vial, 1.50 mg R-PMDI-Δ was dissolved in 400 μL DMF by heating and then 200 μL deionized water was added. Some white precipitates were formed immediately. After sealing the vial, the precipitates were fully dissolved by heating. Colorless transparent plate crystals were observed after standing at room temperature for about 2 days. Pick the right crystal for X-ray single crystal test.
R-PMDI-Δ/Pyr cocrystalDMF
In a 2 mL vial, 0.75 mg R-PMDI-Δ and 0.17 mg pyrene were dissolved in 266 μL DMF by heating. Following this, 133 μL deionized water was added, resulting in the formation of yellow precipitates. The vial was then sealed and the precipitates were fully dissolved by heating. Pale yellow flake R-Δ/Pyr cocrystalsDMF were prepared after standing at room temperature for about 2 days. Pick the right crystal for X-ray single crystal test.
R-PMDI-Δ/Pyr cocrystalNMP
1.0 mg R-PMDI-Δ and 1.82 mg pyrene were dissolved in 600 μL NMP by heating. The solution was then cooled and filtered with a 0.22 μm microporous membrane. The filtrate was transferred to a 2 mL vial which was placed in a 20 mL vial containing 3 mL of water. With slow vapor diffusion of H2O into the NMP solution of R-PMDI-Δ and pyrene, high-quality yellow flake R-Δ/Pyr cocrystalsNMP formed after three days. Pick the right crystal for X-ray single crystal test.Density functional theory calculationDensity functional theory (DFT) computation was performed by Gaussian 09 Revision D.01 program at B3LYP 6-311 G** level. The initial structures of R-PMDI-Δ, CT-complexes and pyrene were extracted from corresponding single crystal data, respectively, and without further geometries optimization.
Macroscopic homochiral helicoids self-assembled via screw dislocations
