Highly photostable near-infrared fluorescent pH indicators and sensors based on BF2-chelated tetraarylazadipyrromethene dyes

TY - JOUR

T1 - Highly photostable near-infrared fluorescent pH indicators and sensors based on BF2-chelated tetraarylazadipyrromethene dyes

AU - Jokic, Tijana

AU - Borisov, Sergey M.

AU - Saf, Robert

AU - Nielsen, Daniel A.

AU - Kühl, Michael

AU - Klimant, Ingo

PY - 2012/8/7

Y1 - 2012/8/7

N2 - In this study, a series of new BF2-chelated tetraarylazadipyrromethane dyes are synthesized and are shown to be suitable for the preparation of on/off photoinduced electron transfer modulated fluorescent sensors. The new indicators are noncovalently entrapped in polyurethane hydrogel D4 and feature absorption maxima in the range 660-710 nm and fluorescence emission maxima at 680-740 nm. Indicators have high molar absorption coefficients of ∼80-000 M-1 cm-1, good quantum yields (up to 20%), excellent photostability and low cross-sensitivity to the ionic strength. pKa values of indicators are determined from absorbance and fluorescence measurements and range from 7 to 11, depending on the substitution pattern of electron-donating and -withdrawing functionalities. Therefore, the new indicators are suitable for exploitation and adaptation in a diverse range of analytical applications. Apparent pKa values in sensor films derived from fluorescence data show 0.5-1 pH units lower values in comparison with those derived from the absorption data due to Förster resonance energy transfer from protonated to deprotonated form. A dual-lifetime referenced sensor is prepared, and application for monitoring of pH in corals is demonstrated.

AB - In this study, a series of new BF2-chelated tetraarylazadipyrromethane dyes are synthesized and are shown to be suitable for the preparation of on/off photoinduced electron transfer modulated fluorescent sensors. The new indicators are noncovalently entrapped in polyurethane hydrogel D4 and feature absorption maxima in the range 660-710 nm and fluorescence emission maxima at 680-740 nm. Indicators have high molar absorption coefficients of ∼80-000 M-1 cm-1, good quantum yields (up to 20%), excellent photostability and low cross-sensitivity to the ionic strength. pKa values of indicators are determined from absorbance and fluorescence measurements and range from 7 to 11, depending on the substitution pattern of electron-donating and -withdrawing functionalities. Therefore, the new indicators are suitable for exploitation and adaptation in a diverse range of analytical applications. Apparent pKa values in sensor films derived from fluorescence data show 0.5-1 pH units lower values in comparison with those derived from the absorption data due to Förster resonance energy transfer from protonated to deprotonated form. A dual-lifetime referenced sensor is prepared, and application for monitoring of pH in corals is demonstrated.

U2 - 10.1021/ac3011796

DO - 10.1021/ac3011796

M3 - Journal article

C2 - 22738322

SN - 0003-2700

VL - 84

SP - 6723

EP - 6730

JO - Industrial And Engineering Chemistry Analytical Edition

JF - Industrial And Engineering Chemistry Analytical Edition

IS - 15

ER -