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UBC Theses and Dissertations

Synthesis and characterization of near-infrared heptamethine indocyanine dyes and intercalated nanocomposites Strohm, Elizabeth-Anne


This thesis describes the synthesis and characterization of a number of novel near-infrared heptamethine indocyanine dyes containing various aromatic chromophores. A known heptamethine indocyanine dye functionalized with a carboxylic acid moiety was employed as a parent dye for subsequent derivatization. Aromatic compounds with terminal hydroxyl groups including a bimetallic cationic organoiron-containing complex, and various anthracene, pyrene, and thiophene derivatives were reacted with the parent dye via ester condensation reactions. Structural analysis of the newly prepared heptamethine indocyanine dyes was accomplished using one- and two-dimensional nuclear magnetic resonance and infrared spectroscopy, and electrospray ionization mass spectrometry. These dyes exhibited high molar absorptivity based on the UV-visible/near-infrared spectral data. Fluorescence emission spectral data was used to determine the relative quantum yield. The formation of H-aggregates was observed in water at low concentrations, but was not present in methanol. In addition, the intercalation of a heptamethine indocyanine dye and indolenine dye into lithium hectorite was reported. This was accomplished by taking advantage of the exfoliating and re-stacking properties of the host, hectorite. The resulting layered nanocomposites were characterized via powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. X-ray diffraction analysis confirmed interlayer expansion. Scanning electron microscopy was employed for surface morphological characterization. Thermal analysis of the resulting intercalated nanocomposites demonstrated greater thermal stability compared to pure hectorite. In addition, the nanocomposites generally exhibited enhanced thermal stability compared to the non-intercalated heptamethine indocyanine dye.

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