Gassensmith, Jeremiah J. Arunkumar, Easwaran Barr, Lorna Baumes, Jeffrey M. DiVittorio, Kristy M. Johnson, James R. Noll, Bruce C. Smith, Bradley D. Self-Assembly of Fluorescent Inclusion Complexes in Competitive Media Including the Interior of Living Cells Anthracene-containing tetralactam macrocycles are prepared and found to have an extremely high affinity for squaraine dyes in chloroform (log <i>K</i><sub>a</sub> = 5.2). Simply mixing the two components produces highly fluorescent, near-infrared inclusion complexes in quantitative yield. An X-ray crystal structure shows the expected hydrogen bonding between the squaraine oxygens and the macrocycle amide NH residues, and a high degree of cofacial aromatic stacking. The kinetics and thermodynamics of the assembly process are very sensitive to small structural changes in the binding partners. For example, a macrocycle containing two isophthalamide units associates with the squaraine dye in chloroform 400 000 times faster than an analogous macrocycle containing two 2,6-dicarboxamidopyridine units. Squaraine encapsulation also occurs in highly competitive media such as mixed aqueous/organic solutions, vesicle membranes, and the organelles within living cells. The highly fluorescent inclusion complexes possess emergent properties; that is, as compared to the building blocks, the complexes have improved chemical stabilities, red-shifted absorption/emission maxima, and different cell localization propensities. These are useful properties for new classes of near-infrared fluorescent imaging probes. squaraine dyes;inclusion complexes;Competitive Media;assembly process;squaraine dye;macrocycle amide NH residues;Squaraine encapsulation;squaraine oxygens;vesicle membranes;isophthalamide units associates;building blocks;chloroform 400 000 times;log Ka;imaging probes;cell localization propensities;binding partners;400 000;Fluorescent Inclusion Complexes;chemical stabilities 2007-12-05
    https://acs.figshare.com/articles/media/Self_Assembly_of_Fluorescent_Inclusion_Complexes_in_Competitive_Media_Including_the_Interior_of_Living_Cells/2971057
10.1021/ja075567v.s004