All solvents used were of Milli‐Q®, spectroscopic or HPLC‐grade.
Absolute ethanol was purchased from VWR Chemicals. Tetrahydrofurane was dried and distilled over potassium.
Trifluoroacetic acid was purchased from Carl Roth (Germany) in PEPTIPURE® ≥99,9 % quality.
Sulfuric acid (≥95 %, Fisher Chemical),
hydrochloric acid (37 %, Anal. Reag. Gr., Fisher Chemical),
acetic acid (Anal. Reag. Gr., ChemSolute), methyl red (Alfa Aesar),
carbonyldiimidazole (97 %, Alfa Aesar),
1,3‐diaminopropane (for synth., Merck),
1,6‐diaminohexane (98 %+, Alfa Aesar) and 1,8‐diaminooctane (98 %, Alfa Aesar) were used as received. 1,8‐Diazabicyclo[5.4.0]undec‐7‐ene was dried over calciumchloride (anhydrous, technical, Bernd Kraft) and distilled
in vacuo. 1,2‐Diaminoethane was distilled
in vacuo.
UV‐vis measurements were performed on a Thermo Scientific™
Evolution™ 220 UV‐Vis‐spectrophotometer. If not stated otherwise, the measurements were done with 100 nm/min and a resolution of 1 nm.
NMR‐measurements were performed on a Jeol EZC 500.
1H‐
1H‐NOESY NMR spectra were measured with a mixing time of 500 ms. 1D‐Spectra were analysed with MestreNova 9. 2D‐Spectra were analysed with Delta 5.3 by JEOL. NMR spectra can be found in the ESI.
Jaik T.G, & Jonas U. (2022). The “Tethered Solvent” Effect – H‐Bonding‐Controlled Thermo‐Halochromism of a Push‐Pull Azo Chromophore via Its Secondary Amidoalkyl Acrylamide Side Chain. Chemphyschem, 24(1), e202200512.