%0 Online Multimedia %A Gassensmith, Jeremiah J. %A Arunkumar, Easwaran %A Barr, Lorna %A Baumes, Jeffrey M. %A DiVittorio, Kristy M. %A Johnson, James R. %A Noll, Bruce C. %A Smith, Bradley D. %D 2007 %T Self-Assembly of Fluorescent Inclusion Complexes in Competitive Media Including the Interior of Living Cells %U https://acs.figshare.com/articles/media/Self_Assembly_of_Fluorescent_Inclusion_Complexes_in_Competitive_Media_Including_the_Interior_of_Living_Cells/2971057 %R 10.1021/ja075567v.s004 %2 https://acs.figshare.com/ndownloader/files/4670329 %K squaraine dyes %K inclusion complexes %K Competitive Media %K assembly process %K squaraine dye %K macrocycle amide NH residues %K Squaraine encapsulation %K squaraine oxygens %K vesicle membranes %K isophthalamide units associates %K building blocks %K chloroform 400 000 times %K log Ka %K imaging probes %K cell localization propensities %K binding partners %K 400 000 %K Fluorescent Inclusion Complexes %K chemical stabilities %X Anthracene-containing tetralactam macrocycles are prepared and found to have an extremely high affinity for squaraine dyes in chloroform (log Ka = 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. %I ACS Publications