Abstract
From investigations into the absorption and fluorescence characteristics of several new meso-amine substituted heptamethine cyanine dyes and the commercially available laser dyes IR140, IR132 and IR144, it appears that these dyes exist in at least two interconvertible ground state isomeric conformations in organic solvents. From the position and nature of absorption and fluorescence characteristics, it is concluded that these conformers differ in the contribution to the chromophore of the meso-amine substituent, which either acts as an electron-donor by resonance or else withdraws by induction. Fluorescence emission below 900 nm can only be attributed to the conformer in which the meso-amine groups acts as an electron-donor by resonance. This gives rise to a system that is analogous to the allopolar isomerism exhibited by holomeropolar cyanine dyes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
