METHOD OF QUENCHING SINGLET AND TRIPLET EXCITED STATES OF PHOTODEGRADABLE PIGMENTS, SUCH AS PORPHYRIN COMPOUNDS, PARTICULARLY PROTOPORPHYRIN IX, WITH CONJUGATED FUSED TRICYCLIC COMPOUNDS HAVING ELECTRON WITHDRAWING GROUPS, TO REDUCE GENERATION OF SINGLET OXYGEN
A method of quenching excited state energy from a photodegradable pigment that has been excited by absorption of light having a wavelength in the wavelength range of 290-800 nm, comprising reacting a pigment with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:wherein: A is selected from the group consisting of O, S, C═O, C═S,B1, B2, D1 and D2 are each independently selected from the group consisting of F, Cl, Br, I, CF3, CC13, NR33+, NO2, CN, C(=0)R4, C(═O)OR′, SO2R5, aryl, and —C═CHR6；each m independently is 0, 1, 2, 3, or 4；a is 0 or 1；each R′ is independently selected from the group consisting of LI, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl；R2 is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl；each R3 is independently selected from the group consisting of H and C1-C6 alkyl；each R4 is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl；each R5 is independently selected from the group consisting of H, O, OH, NH2, and Cl； andeach R6 is-independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl.
