title: Artificial receptors that provides a preorganized hydrophobic environment: a biomimetic approach to dopamine recognition in water.
abstract: [structure: see text] The recognition of dopamine in water has been achieved with tripodal oxazoline-based artificial receptors, capable of providing a preorganized hydrophobic environment by rational design, which mimics a hydrophobic pocket predicted for a human D2 receptor. The receptors show an amphiphilic nature owing to the presence of hydrophilic sulfonate groups at the periphery of the tripodal oxazoline ligands, which seems to contribute in forming the preorganized hydrophobic environment. The artificial receptors recognized dopamine hydrochloride in water with reasonable selectivity among various organoammonium guests examined. The observed binding behavior of the receptors was explained by evoking guest inclusion in the preorganized hydrophobic pocket-like environment and not by simple ion-pairing interactions. The rationally predicted 1:1 inclusion binding mode was supported by binding studies such as with a reference receptor that cannot provide a similar binding pocket, Job and VT-NMR experiments, electrospray ionization mass analysis, and guest selectivity data. This study implies that an effective hydrophobic environment can be generated even from an acyclic, small molecular artificial receptor. Such a preorganized hydrophobic environment, as being utilized in biological systems, can be effectively used as a complementary binding force for the recognition of organoammonium guests such as dopamine hydrochloride in water.
authors.affiliation: Department of Chemistry and Centre for Integrated Molecular Systems, Pohang University of Science and Technology, San 31 Hyoja Dong, Pohang 790-784, Republic of Korea.
authors.forename: Jeongryul
authors.initials: J
authors.lastname: Kim
authors.forename: Balamurali
authors.initials: B
authors.lastname: Raman
authors.forename: Kyo Han
authors.initials: KH
authors.lastname: Ahn
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D011954:Receptors, Dopamine / Q000737:chemistry* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D017186:Titrimetry; D014867:Water
chemical_list: D007477:Ions; D000644:Quaternary Ammonium Compounds; D011954:Receptors, Dopamine; D014867:Water; D004298:Dopamine