Diazocines
are bridged azobenzenes with superior photophysical
properties. In contrast to azobenzenes the Z configuration
is thermodynamically stable and the E isomer is metastable.
We present a new class of nitrogen bridged diazocines with bathochromically
shifted switching wavelengths and remarkably high quantum yields (−NH–CH2− bridged diazocine: ΦZ→E =
0.57, ΦE→Z = 0.8). Z to E isomerization is induced by irradiation with blue light,
whereas switching back to the Z isomer is accomplished
with light in the near-infrared window (up to 740 nm), which is important
for medical applications like photopharmacology (deep tissue penetration).
Furthermore, substitution at the bridging nitrogen should provide
access to widely applicable tricyclic, photoswitchable pharmacophores.
The −NAc–CH2− bridged derivative is
soluble in water, and all photophysical properties (conversion rates,
quantum yields, and thermal half-lives) are largely retained. Hence,
this diazocine is an ideal photoswitch for applications in biochemical
systems and in photopharmacology.
Azo-N-methylimidazole functionalized Ni(ii)porphyrins were rationally designed and synthesized and their performance as molecular spin switches was investigated. They perform intramolecular light-driven coordination-induced spin state switching (LD-CISSS) in the presence of water and therefore are an important step towards spin switches for medicinal applications, particularly functional MRI contrast agents.
Increasing field strengths in MRI necessitate the examination of potential side effects. Previously reported results have been contradictory, possibly caused by imbalanced samples. We aimed to examine whether special groups of people are more prone to develop side effects that might have led to contradictory results in previous studies. We examined the occurrence of sensory side effects in static magnetic fields of MRI scanners of 1.5, 3, and 7 T and a mock scanner in 41 healthy participants. The contribution of field strength, sex, age, and attention to bodily processes, and stress hormone levels to the sensation of dizziness was examined in separate univariate analyses and in a joint analysis that included all variables. Field strength and sex were significant factors in the joint analysis (P=0.001), with women being more strongly affected than men by dizziness in higher static magnetic fields. This effect was not mediated by the other variables such as attention to bodily symptoms or stress hormones. Further research needs to elucidate the underlying factors of increased dizziness in women in static magnetic fields in MRI. We hypothesize that imbalanced samples of earlier studies might be one reason for previous contradictory results on the side effects of static magnetic fields.
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