On titration with CT-DNA, complex 1 exhibits slight hypochromic and narrow
bathochromic effects; whereas, complex 2 displays significant hypochromic and large
bathochromic effects; moreover, complex 3 shows slight hyperchromic and narrow hypsochromic effects.
Once the shifts means the appearing of stretching frequencies at lower energy values in the electromagnetic spectrum, these events are well known as red- shifts rather than the
bathochromic effect widely cited [120].
Meanwhile, larger
bathochromic shift was observed in fibers than in films, because the [pi] -[pi] interaction of electrospun membrane was stronger than that of coating film.
Otherwise the conjugation length would be larger and a
bathochromic shift would be observed.
When diluted in distilled water (pH = 3.8) or in methanol (pH = 12), maximum absorption peaks can be observed in three bands: 243~243.5nm, 280~282nm, and 324~331nm, respectively, with a slight
bathochromic shift, but with a strong hypsochromic shift at a wavelength from 383.6 nm to 302.5 nm.
The absorption wavelengths of complexes (1)-(4) have shifted towards longer wavelengths (
bathochromic shift) compared to the wavelengths of the reactants (copper, ferrozine, and ferene).
Generally, the better conjugation in the thiophene-based analogue would cause some small
bathochromic shift of the band maximum, not only its broadening.
It can be seen as expected that there is a gradual systematic
bathochromic shift of the important MLCT transition as the electron affinity of the functional group located on the polypyridyl ligand is increased.
The
bathochromic shifts of asymmetric ([v.sub.as]) and hypsochromic shifts of symmetric ([v.sub.s]) frequencies are also observed.