7-Amino-4-(Trifluoromethyl)Coumarin

7-Amino-4-(trifluoromethyl)coumarin (AFC, Coumarin 151) is a fluorescent marker for the sensitive detection of proteinases. The excitation and emission wavelengths are 400 and 490 nm, respectively.

In Vitro:Amino acid and peptide derivatives of 7-amino-4-(trifluoromethyl)coumarin are used to monitor peptidase activities. Caspase activation is measured using the fluorogenic compound N-acetyl-asp-glu-val-asp-7-Amino-4-(trifluoromethyl)coumarin (Ac-DEVD-AFC). This substrate rapidly enters cells where it is efficiently cleaved at the aspartate residue by specific caspases, yielding the fluorescent compound 7-Amino-4-(trifluoromethyl)coumarin (AFC). Following cell disruption, released 7-Amino-4-(trifluoromethyl)coumarin is separated on HPLC and detected by fluorescence. The appearance of 7-Amino-4-(trifluoromethyl)coumarin in cells is blocked by the pancaspase inhibitor benzyloxycarbonyl-val-ala-asp-fluoromethylketone, thus establishing that intracellular caspases are responsible for the cleavage[1]. γ-glutamyl-7-amino-4-(trifluoro-methyl)coumarin is synthesized and used as a substrate for fluirimetric assay of γ-gluta-myltranspeptidase. The reaction product 7-amino-4-(trifluoromethyl)coumarin is fluorescent at neutral pH values and with excitation and emission wavelengths of 400 and 490 nm, respectively, concentration is linearly related to fluorescence over the range of 10 to 300 pmol/3 mL reaction mixture[2].

References:
[1]. Tao Z, et al. Caspase activation by anticancer drugs: the caspase storm. Mol Pharm. 2007 Jul-Aug;4(4):583-95. [2]. White IN, et al. A continuous fluorometric assay for gamma-glutamyltranspeptidase. Anal Biochem. 1996 Jan 1;233(1):71-5.

Using a Multi-Shelled Hollow Metal-Organic Framework as a Host to Switch the Guest-to-Host and Guest-to-Guest Interactions.[Pubmed:29266678]

Angew Chem Int Ed Engl. 2018 Feb 19;57(8):2110-2114.

A bio-inspired design of using metal-organic framework (MOF) microcrystals with well-defined multi-shelled hollow structures was used as a matrix to host multiple guests including molecules and nanoparticles at separated locations to form a hierarchical material, mimicking biological structures. The interactions such as energy transfer (ET) between different guests are regulated by precisely fixing them in the MOF shells or encapsulating them in the cavities between the MOF shells. The proof-of-concept design is demonstrated by hosting chromophore molecules including rhodamine 6G (R6G) and 7-Amino-4-(Trifluoromethyl)Coumarin (C-151), as well as metal nanoparticles (Pd NPs) into the multi-shelled hollow zeolitic imidazolate framework-8 (ZIF-8). We could selectively establish or diminish the guest-to-framework and guest-to-guest ET. This work provides a platform to construct complex multifunctional materials, especially those need precise separation control of multi-components.

A TDDFT/EFP1 study on hydrogen bonding dynamics of coumarin 151 in water.[Pubmed:25203215]

Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 25;137:99-104.

Change in energy of hydrogen bonds (HBs) upon excitation, plays an important role on the spectra of chemical and biological molecules. Effective fragment potential (EFP) method of explicit water molecules embedded in polarizable continuum medium (PCM) is used for the solvation of 7-Amino-4-(Trifluoromethyl)Coumarin (C151). Time dependent density functional theory (TDDFT) calculations combined with EFP/PCM had been carried out to study the electronic structure and the exited state properties of C151 with five water molecules (C151-(H2O)5 complex). S0 state and S1 state geometries were optimized using DFT/TDDFT with PBE0 functional combined with cc-pVDZ basis set, the transition energies are computed with same basis set and functional. Change in HB energy is calculated using the procedure proposed by T. Nagata et al. to calculate solute-solvent interaction energy in Nagata et al. (2011). Upon photoexcitation of C151-(H2O)5 complex, A type (Ncdots, three dots, centeredH-O) HB is weakened with decrease of energy by 4.37 kJ/mol, whereas B and C type (C=Ocdots, three dots, centeredH-O and N-Hcdots, three dots, centeredO) HBs are strengthened with increase of 5.62 and 10.21 kJ/mol energy, respectively. This study again confirmed that the intermolecular hydrogen bonds between C151 chromophore and aqueous solvents are strengthened, not cleaved upon electronic excitation.