Novel reversible Zn2+-assisted biological phosphate "turn-on" probing through stable aryl-hydrazone salicylaldimine conjugation that attenuates ligand hydrolysis.
A novel reversible zinc(II) chemosensing ensemble (2·Zn(2+)) allows for selective "turn-on" fluorescence sensing of ATP and PPi in aqueous media (detection limits: 2.4 and 1.0 μM, respectively) giving selective binding patterns: ATP ∼ PPi > ADP ≫ AMP > monophosphates ≈ remaining ions tested. The conjugated hydrazone [C═N-NH-R] resists hydrolysis considerably, compared to the imine [C═N-CH2-R, pyridin-2-ylmethanamine] functionality, and generalizes to other chemosensing efforts. Prerequisite Zn(2+)·[O(phenol)N(imine)N(pyr)] binding is selective, as determined by UV-vis and NMR spectroscopy; ATP or PPi extracts Zn(2+) to regenerate the ligand-fluorophore conjugate (PPi: turn-on, 512 nm; detection limit, 1.0 μM). Crystallography, 2-D NMR spectroscopy, and DFT determinations (B3LYP/631g*) support the nature of compound 2. 2-Hydrazinyl-pyridine-salicylaldehyde conjugation is unknown, as such; a paucity of chemosensing-Zn(2+) binding reports underscores the novelty of this modifiable dual cation/anion detection platform. A combined theoretical and experimental approach reported here allows us to determine both the potential uniqueness as well as drawbacks of this novel conjugation.
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
Olga G
OG
Tsay
Sudesh T
ST
Manjare
Hyungjun
H
Kim
Kang Mun
KM
Lee
Yoon Sup
YS
Lee
David G
DG
Churchill
D000255:Adenosine Triphosphate / Q000032:analysis*; D001896:Boron Compounds / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006835:Hydrazones / Q000737:chemistry*; D006868:Hydrolysis; D008024:Ligands; D008958:Models, Molecular; D011122:Polyphosphates / Q000032:analysis; D012459:Salicylates / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods; D015032:Zinc / Q000737:chemistry*
C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D005456:Fluorescent Dyes; D006835:Hydrazones; D008024:Ligands; D011122:Polyphosphates; D012459:Salicylates; D000255:Adenosine Triphosphate; D015032:Zinc