Development of molecular cassettes for the excitation energy transfer in the red region of the spectrum

Transcription

1 Development of molecular cassettes for the excitation energy transfer Josué Jiménez, a Alejandro Villacampa, a Antonia R. Agarrabeitia, a Florencio Moreno, a Beatriz L. Maroto, a Jorge Bañuelos, b Íñigo López Arbeloa, b María J. Ortiz, a Santiago de la Moya a a Departamento de Química Orgánica I. Facultad de Ciencias Químicas. Universidad Complutense de Madrid. Ciudad Universitaria s/n, Madrid, Spain. b Departamento de Química Física, Universidad del País Vasco UPV/EHU, Aptdo. 644, Bilbao, Spain. santmoya@ucm.es, belora@ucm.es

2 Introduction and background EET Donor Chromophore Acceptor Chromophore Excitation Energy Transfer (EET) Cassettes Advanced materials for photonic technologies: - Solar harvesting - Fluorescence microscopy - Biomolecular probing

3 Introduction and background Modulable organic fluorophores - High molar absorption coefficients (ε) - High fluorescence quantum yields ( ) - Sharp fluorescence peaks BODIPYs Easily derivatizable APPLICATIONS Development of photonic tools: - bioimaging - chemosensing - lasing

4 Introduction and background Small Stokes shifts - Reabsorption of emitted light - Effects from excitation light scattering BODIPYs Development of Energy Transfer Cassettes with large pseudo-stokes shifts

5 Introduction and background BODIPY 1 2 n-hexane exc (nm) λ flu (nm) (%) Δν St (cm 1 ) , Sánchez-Carnerero, E. M.; Gartzia Rivero, L.; Moreno, F.; Maroto, B. L.; Agarrabeitia, A. R.; Ortiz, M. J.; Bañuelos, J.; López- Arbeloa, I.; de la Moya, S. Chem. Commun. 2014, 50,

6 Objectives Fluorophores with medical applications red/nir region biological window ( nm): - Minimize autofluorescence - Minimize absorption by water, tissues and cells - Less light scattering Deeper penetration by incident light? Red emission

7 Objectives flu (hexane) = (hexane) = 0.36 red emission flu (hexane) = (hexane) = 0.74 red emission Cassette? Cassette?

8 Results Synthesis

9 Results Photophysical properties BODIPY solvent ab (nm) max 10-4 (M -1 cm -1 ) λ fl (nm) Δν St (cm -1 ) PM650 c-hexane * acetone * Ф 3 n-hexane ** ** ** acetone ** ** ** ICT PM605 n-hexane acetone n-hexane acetone *Fluorescence deactivation by ICT due to the strongly electron-withdrawing cyano group. **No signal was detected. ICT High deactivation of the fluorescence!! Intramolecular Charge Transfer (ICT): From electron rich O-BINOL to electron poor BODIPY Problem

10 Results Photophysical properties Solution ICT Less electron-donor O-BINOL ICT ICT? ICT? ICT High deactivation of the fluorescence!! Intramolecular Charge Transfer (ICT): From electron rich O-BINOL to electron poor BODIPY Problem

11 Results Synthesis

12 Results Photophysical properties BODIPY solvent ab (nm) max 10-4 (M -1 cm -1 ) λ fl (nm) Δν St (cm -1 ) PM650 c-hexane acetone n-hexane acetone n-hexane acetone PM605 n-hexane acetone n-hexane acetone n-hexane acetone Ф High improvement of the fluorescence!! Less deactivation by ICT

13 Results EET behaviour BODIPY 5 6 n-hexane exc (nm) λ flu (nm) (%) Δν St (cm 1 ) EET 100%, large pseudo-stokes shift, red emission

14 Conclusions Effcient EET cassette with red emission red BODIPY Electron-withdrawing groups diminish ICT EET 100% up to 60% Fluorescence