2-Quinolone and coumarin polymethines for the detection of proteins using fluorescence

A series of novel, polymethine chalcone dye – 2-quinolone derivatives and their boron difluoride complexes were synthesized. The spectral-luminescence properties of a series of 2-quinolones and their coumarin analogues were characterized in the presence of a denaturing agent (sodium dodecyl sulfate), native bovine serum albumin as well as a combination of serum albumin and sodium dodecyl sulfate. A study of the influence of the BF2-ether group on the sensitivity of the polymethine dyes to proteins revealed that three of the dyes, namely two hydroxyquinoline dyes containing a 4-diethylamino-2-hydroxyphenyl substituent and a coumarine dye that contained an indolenine substituent, displayed high emission and bright fluorescence (quantum yield ≤ 0.27) and thus offer promise for use in protein detection.