Coumarin-appended cyclophanes bearing positively or negatively charged side chains were synthesized as a water-soluble host (1a or 1b, respectively). Host 1a and 1b showed fluorescence bands with fluorescence maxima at 404 nm originated from coumarin moiety. As a host for guest molecules by using macrocyclic cavity, cationic host 1a binds anionic guests such as 6-p-toluidinonaphthalene-2-sulfonate (TNS), 6-anilinonaphthalene-2-sulfonate (2,6-ANS), and 8-anilinonaphthalene-1-sulfonate (1,8-ANS) more strongly than anionic host 1b, reflecting intermolecular electrostatic interactions. In addition, both host 1a and 1b showed protein surface recognition and fluorescence response toward myoglobin, a small and globular protein. The fluorescence intensity originating from the hosts decreased upon the addition of myoglobin, reflecting the formation of 1a-and 1b-myoglobin complexes. On the other hand, such fluorescence response of 1a and 1b was almost negligible for other proteins such as egg white albumin, bovine serum albumin, human albumin, concanavaline A, fibrinogen, c-globlin, peanut agglutinin, trypsin, and lysozyme.
The title compound of N,N¢-bis(3,5-dichlorophenyl)formamidine, which is abbreviated as H(3,5-Cl2-pf), was isolated, and the crystal structure was determined by the single-crystal X-ray diffraction method at 90 K. It crystallizes in the triclinic space group P1 with a = 7.9265(13)Å, b = 9.3588(15)Å, c = 10.4003(17)Å, a = 76.579(3)˚, b = 72.529(2)˚, g = 74.249(2)˚, V = 698.7(2)Å 3 , Dx = 1.588 g/cm 3 , and Z = 2. The R1 [I > 2s(I)] and wR2 (all data) values are 0.0276 and 0.0771, respectively, for all 3046 independent reflections. The C-N (amine) single bond (1.3486(18)Å) and C=N (imine) double bond (1.2836(18)Å) within the H(3,5-Cl2-pf) molecule were confirmed. Two H(3,5-Cl2-pf) molecules are associated with a set of hydrogen bonds through each amine and imine nitrogen atoms with a N amine •N imine distance of 3.0264(17)Å.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.