Symmetrical and Asymmetrical Cyanine Dyes. Synthesis, Spectral Properties, and BSA Association Study

Abstract

New cyanines were prepared by an efficient and practical route with satisfactory overall yield from low-cost starting materials. The photophysical behavior of the cyanines was investigated using UV-vis and steady-state fluorescence in solution, as well as their association with bovine serum albumin (BSA) in phosphate buffer solution (PBS). No cyanine aggregation was observed in organic solvents or in phosphate buffer solution. The alkyl chain length in the quaternized nitrogen was shown to be fundamental for BSA detection in PBS in these dyes.

Increasing Photovoltaic Performance of an Organic Cationic Chromophore by Anion Exchange

“…This broadening is favorable for OPV applications and is caused to a significant extent by aggregation effects in the solid state. In ethanol solution, a vibronic shoulder shifted by 1070 cm −1 is visible, suggesting 0 → 0 transitions for the main peak and 0 → 1 or 0 → 2 transitions for the shoulders at shorter wavelengths caused by a dominant vibrational mode 39. In spincast films the shoulder is blueshifted by about 1230 cm −1 and reaches almost the same intensity as the absorbance maximum, pointing toward dimerization as proposed in the literature 40.…”

Using membrane composition to fine-tune the pKa of an optical liposome pH sensor

“…This is consistent with the red shift observed when cyanine dyes are measured in organic solvents compared to aqueous buffer, and suggests that the dye component in probe 2 embeds into the membrane interfacial region. 22 A similar red shift effect (10 nm) is apparent when the absorption maxima for the acidic form of dye 3 in water is compared to the corresponding band for cholesterol–linked probe 4 incorporated into POPC liposomes.…”

Wavelength-dependent optoacoustic imaging probes for NMDA receptor visualisation

“…The shoulder at 712 nm is also π→π * mode, relating to the 0→1 or 0→2 vibronic transitions. 13 These absorption properties makes them excellent candidates as NMDAR-targeted probes for MSOT, with the maximum wavelength of absorption falling in the near-infrared (NIR) window where the majority of endogenous chromophores do not strongly absorb. In this region, light scattering is relatively low resulting in greater light penetration, allowing images to be obtained from deeper within the body.…”