Crystal system: orthorhombic
| a: | 8.9098 (±0.0002) Å |
| b: | 28.7413 (±0.0006) Å |
| c: | 9.3567 (±0.0002) Å |
| α: | 90° |
| β: | 90° |
| γ: | 90° |
Starting materials: (R)-(+)-α-Methylbenzylamine (R-MBA, 98%, ee 96%), (S)-(−)-α-methylbenzylamine, (S-MBA, 98%, ee 98%), (±)-α-methylbenzylamine (rac-MBA, 99%), tTin(IV) oxide (SnO2, 99.9%), hydriodic acid solution (HI, 57% w/w in water, 99.95%, distilled, stabilized by H3PO2), hypophosphorous acid (H3PO2, 50% w/w in water)
Product: Orange crystals
Description: SnO2 (0.896 mmol), MBA (R-, S-, or rac-; 1.57 mmol), HI (5.5 mL), and H3PO2 (0.5 mL) were mixed. The solution was heated to 120 degrees Celsius and stirred until it became clear and yellow. Its vial was then put in an oil bath at 90 degrees and then underwent slow cooling at the rate of 1 degree per hour, eventually yielding orange rods. The crystals were filtered in a nitrogen atmosphere and were vacuum dried overnight.
Method: Single-crystal X-ray diffraction
Description: A Rigaku XtaLAB Synergy-S instrument using Mo Kalpha radiation was used for SCXRD at 250 K. The SHELXS program was used to directly solve the structure and the SHELXL program from the Olex2 package was used for refinement.
Starting materials: (R)-(+)-α-Methylbenzylamine (R-MBA, 98%, ee 96%), (S)-(−)-α-methylbenzylamine, (S-MBA, 98%, ee 98%), (±)-α-methylbenzylamine (rac-MBA, 99%), tTin(IV) oxide (SnO2, 99.9%), hydriodic acid solution (HI, 57% w/w in water, 99.95%, distilled, stabilized by H3PO2), hypophosphorous acid (H3PO2, 50% w/w in water), N,N-anhydrous DMF
Product: Thin film on quartz substrate
Description: SnO2 (0.896 mmol), MBA (R-, S-, or rac-; 1.57 mmol), HI (5.5 mL), and H3PO2 (0.5 mL) were mixed. The solution was heated to 120 degrees Celsius and stirred until it became clear and yellow. Its vial was then put in an oil bath at 90 degrees and then underwent slow cooling at the rate of 1 degree per hour, eventually yielding orange rods. The crystals were filtered in a nitrogen atmosphere and were vacuum dried overnight. The crystals were dissolved in DMF at the desired concentration to be used as precursors for spin coating. A spin rate of 4000 rpm for 30 seconds was used and was followed by annealing at 100 degrees for 10 minutes. Linear optical and CD measurements were made on the quartz films, and mCP-AFM measurements were made on the FTO films.
Method: Circular Dichroism (CD) Spectroscopy
Description: A Jasco J-715 spectropolarimeter was used for the CD measurements. 3-5 scans of the spectra were taken and averaged. A wavelength range of 200-600 nm was used with 0.2 nm resolution.
Starting materials: (R)-(+)-α-Methylbenzylamine (R-MBA, 98%, ee 96%), Tin(IV) oxide (SnO2, 99.9%), hydriodic acid solution (HI, 57% w/w in water, 99.95%, distilled, stabilized by H3PO2), hypophosphorous acid (H3PO2, 50% w/w in water), N, N-anhydrous DMF
Product: Thin-film on FTO substrate
Description: SnO2 (0.896 mmol), R-MBA (1.57 mmol), HI (5.5 mL), and H3PO2 (0.5 mL) were mixed. The solution was heated to 120 degrees Celsius and stirred until it became clear and yellow. Its vial was then put in an oil bath at 90 degrees and then underwent slow cooling at the rate of 1 degree per hour, eventually yielding orange rods. The crystals were filtered in a nitrogen atmosphere and were vacuum dried overnight. The crystals were dissolved in DMF at the desired concentration to be used as precursors for spin coating. A spin rate of 4000 rpm for 30 seconds was used and was followed by annealing at 100 degrees for 10 minutes.
Method: Magnetic conductive-probe atomic force microscopy
Description: The mCP-AFM measurements were made using a Bruker Icon AFM system enclosed within an Argon glovebox. The specific tip used was the “Bruker MESP-V2”, and contact mode was selected. The Co-Cr coated tips were premagnetized through exposure to a strong permanent magnet for about an hour, scanning immediately afterwards. The magnetization of the tip causes the spin-degeneracy of the carriers in the tip to be lifted, causing mostly one spin-state to be injected into the sample. While scanning, the tip was grounded, and a bias was applied to the sample in the range of -1.2 to 1.2 V. A scan rate of 0.3 Hz was used. Over 100 I-V curves were generated and averaged at different locations on the sample for the three different magnetizations (north, south, none).