Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• )-porphyrins; photoswitch; record player molecules; spin state; spin switch; Introduction Molecular spin switches operated with visible light in homogeneous solution [1] or on surfaces [2], hold promise for a number of hitherto unprecedented applications such as switchable contrast agents [3][4][5][6][7

• substituents at the pyridine or imidazole part) to increase the Ni–ligand coordination strength. Strong coordination in turn improves the performance of the spin switch, namely the conversion rate to the cis isomer, the conversion rate to the high-spin state, as well as the thermal stability of the high-spin

• state. 4-Substituted pyridines exhibit a distinguished correlation between basicity and coordination strength as axial ligands with Ni-porphyrins [12]. Hence, Hammet σ values might be used to predict and to systematically optimize the performance of the spin switch. In previous studies we have shown

Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

• Jannis Ludwig,
• Julian Helberg,
• Hendrik Zipse and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179

• activity. The rate constants in the two switching states differ by a factor of 2.2, and the catalytic switching is reversible. Keywords: catalysis; Ni(II)-porphyrins; nucleophilic catalyst; photoswitch; record player molecules; spin switch; Introduction Photoswitchable catalysis has been realized

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• gold. To investigate this mechanism further and to examine scope and limitation of the “spin-switch catalysis” we now prepared analogous diazocine systems. Diazocines, in contrast to azobenzenes, are stable in the cis-configuration. Upon irradiation with light of 405 nm the cis-configuration isomerizes